Reactions of Half-Sandwich Ethene Complexes of Rhodium(I ...

Article
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Reactions of Half-Sandwich Ethene Complexes of Rhodium(I) toward
Iodoperfluorocarbons: Perfluoro-alkylation or -arylation of
Coordinated Ethene versus Oxidative Addition †
Juan Gil-Rubio,* Juan Guerrero-Leal, María Blaya, and JoséVicente
Grupo de Química Organometaĺica, Departamento de Química Inorgańica, Facultad de Química, Universidad de Murcia,
E-30071 Murcia, Spain
Delia Bautista
SAI, Universidad de Murcia, E-30071 Murcia, Spain
Peter G. Jones
Institut für Anorganische und Analytische Chemie, Technische Universitaẗ Braunschweig, Postfach 3329, 38023 Braunschweig,
Germany
*S Supporting Information
ABSTRACT: Perfluoroalkylation or perfluoroarylation of coordinated
ethene takes place when complexes [Rh(η 5 -Cp*)-
(η 2 -C 2 H 4 ) 2 ]or[Rh(η 5 -Cp*)(η 2 -C 2 H 4 )(PR 3 )] react with IR F ,to
give complexes [Rh(η 5 -Cp*)(CH 2 CH 2 R F )(μ-I)] 2 (R F =CF(CF 3 ) 2
(1a), CF(CF 3 )CF 2 CF 3 (1b), or C(CF 3 ) 3 (1c)) and [(η 5 -Cp*)-
IRh(μ-I) 2 Rh(η 5 -Cp*)(CH 2 CH 2 R F )] (2a−c), or [Rh(η 5 -Cp*)-
(CH 2 CH 2 R F )I(PR 3 )] (R = Me, R F = CF(CF 3 ) 2 (3a), C(CF 3 ) 3 (3c), C 6 F 5 (3d); R = Ph, R F =CF(CF 3 ) 2 (3a′), CF 2 C 6 F 5 (3e′)),
respectively. Bridge splitting reactions of 1a, 1b, or1c with phosphines afford complexes [Rh(η 5 -Cp*)(CH 2 CH 2 R F )I(PR 3 )] (3a, 3a′,
3c; R F = CF(CF 3 ) 2 ,R= i Pr (3a″); R F = CF(CF 3 )CF 2 CF 3 ,R=Me(3b), Ph (3b′)). In contrast, oxidative addition dominates over
addition to ethene in the reactions of [Rh(η 5 -Cp*)(η 2 -C 2 H 4 )(PMe 3 )] with IR F (R F =CF 2 C 6 F 5 , n C 3 F 7 , n C 4 F 9 ,CFCF 2 )andinthe
reaction of [Rh(η 5 -Cp)(η 2 -C 2 H 4 )(PMe 3 )] with I n C 4 F 9 , affording complexes of the type [Rh(η 5 -C 5 R 5 )(R F )I(PMe 3 )] (4e−h and 5,
respectively). The reaction of [Rh(η 5 -Cp*)(η 2 -C 2 H 4 )(PR 3 )] with ICF(CF 3 )CF 2 CF 3 gives a mixture of cis- andtrans-octafluoro-2-
butene as the main fluoroorganic reaction product. Evidence for the intermediacy of R F − anions in these reactions has been obtained.
3a′ reactswithAgOTf(OTf=O 3 SCF 3 ) and XyNC or CO to give complexes [Rh(η 5 -Cp*){CH 2 CH 2 CF(CF 3 ) 2 }(CNXy)(PPh 3 )]OTf
(6) or[Rh(η 5 -Cp*){C(O)CH 2 CH 2 CF(CF 3 ) 2 }(CO)(PPh 3 )]OTf (7), respectively. Complex [Rh(η 5 -Cp*)I(py)(PMe 3 )]BF 4 (8) was
obtained either by reaction of (1) [Rh(η 5 -Cp*)(η 2 -C 2 H 4 )(PMe 3 )] with [I(py) 2 ]BF 4 or (2) [Rh(η 5 -Cp*)I 2 (PMe 3 )] with AgBF 4 and
py. The crystal structures of 1a, 1b, 3c, 4g, 7, and8 have been determined.
■ INTRODUCTION
Despite the notable advances recently made in the field of
metal-catalyzed perfluoroalkylation of organic substrates, 1−3
processes involving perfluoroalkyl metal complexes as intermediates
remain a challenge, because of the reluctance of these
complexes to undergo typical C−C bond formation reactions,
such as reductive elimination or insertion of unsaturated
molecules into the M−C bond. 4−10 Alternatively, some metal
complexes are effective initiators of free radical perfluoroalkylations,
11−16 but the selectivity of these reactions is difficult to
control. 11,13,17 In this context, the direct perfluoroalkylation
of a substrate coordinated to a metal is of potential interest, 18
since it provides a way to the selective formation of C−
perfluoroalkyl bonds avoiding the intermediacy of stable
metal perfluoroalkyls.
Perfluoroiodocarbons usually react with complexes of the
type [M(η 5 -C 5 R 5 )L 2 ] (M = Co, Rh or Ir; R = H or Me; L = CO
or PF 3 ) by oxidative addition to give complexes [M(η 5 -C 5 R 5 )I-
(R F )L], where R F is a perfluorinated alkyl, aryl, or benzyl
group. 19−31 However, reactions involving perfluoroalkylation
of ligands have been observed in a few cases (Scheme 1). For
instance, clean perfluoroalkylation at the η 5 -Cp ring was
observed in the reactions of [M(η 5 -Cp)(PMe 3 ) 2 ](M=Coor
Rh) with I n C 3 F 7 or ICF(CF 3 ) 2 , 24,29,30 whereas mixtures of products
resulting from perfluoroalkylation at the metal, CO, or η 5 -Cp
ligands were formed in the reactions of [M(η 5 -Cp)(PMe 3 )(CO)]
Special Issue: Fluorine in Organometallic Chemistry
Received: October 10, 2011
Published: November 29, 2011
© 2011 American Chemical Society 1287 dx.doi.org/10.1021/om2009588 | Organometallics 2012, 31, 1287−1299

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Scheme 1
Article
the Rh−C bond 44−46 occurred to afford an unusual highly
fluorinated
■
acyl derivative.
RESULTS AND DISCUSSION
Reactions of [Rh(η 5 -Cp*)(η 2 -C 2 H 4 ) 2 ] with Perfluoroiodocarbons.
[Rh(η 5 -Cp*)(η 2 -C 2 H 4 ) 2 ] reacts with IR F
(Scheme 2) to give mainly ethene and complexes [Rh(η 5 -
Scheme 2
(M = Rh or Ir) with the same perfluoroalkyl iodides. 32 Very
recently, the perfluoroalkylation of a CO ligand in the reaction
between [Ir(η 5 -Cp*)(CO) 2 ] and perfluorocyclohexyl bromide
has been reported. 33
Although complexes [Rh(η 5 -C 5 R 5 )(η 2 -C 2 H 4 )L] (R = H or
Me; L = phosphine or C 2 H 4 ) 34−37 have been known for a long
time, reports of their reactivity toward perfluoroalkyl iodides
or bromides are scarce. Thus, [Rh(η 5 -Cp)(η 2 -C 2 H 4 ) 2 ]was
reportedtoreactwithICF 3 or I n C 3 F 7 to give the oxidative
addition products [Rh(η 5 -Cp)(CF 3 )(μ-I)] 2 or [Rh(η 5 -Cp)I-
( n C 3 F 7 )(η 2 -C 2 H 4 )], 38 respectively. In contrast, [Rh(η 5 -C 5 Me 5 )-
(η 2 -C 2 H 4 ) 2 ] does not react with ICF 2 C 6 F 5 . 39 The reactions of
[Rh(η 5 -Cp)(η 2 -C 2 H 4 )(PPh 3 )] with I n C 3 F 7 or BrCF 2 CF 2 Br also
proceed by oxidative addition, yielding compounds [Rh(η 5 -Cp)-
(R F )X(PPh 3 )] (X = I, R F = n C 3 F 7 ;X=Br,R F =CF 2 CF 2 Br), but
the analogous reaction with ICF 3 affords [Rh(η 5 -Cp)I 2 (PPh 3 )]
as the only isolated product. 40 Oxidative addition of perfluoroalkyl
iodides to the related complex [Rh(Tp)(η 2 -C 2 H 4 ) 2 ](Tp=
tris(pyrazolyl)borate) has also been described. 41 Therefore, we
decided to improve and extend the knowledge of the reactivity
of complexes of the type [Rh(η 5 -C 5 R 5 )(η 2 -C 2 H 4 )L] (R = H, Me;
L=PR 3 ,C 2 H 4 ) toward iodoperfluorocarbons. Interestingly,
these reactions proceed in most cases by perfluoroalkylation of
the coordinated ethene, rather than by oxidative addition. As far
as we are aware, perfluoroalkylation of coordinated ethene has
been reported only in the reaction of complexes [M(η 5 -Cp) 2 -
(η 2 -C 2 H 4 )] (M = Mo or W) with IC(CF 3 ) 3 to give [M(η 5 -
Cp) 2 {CH 2 CH 2 C(CF 3 ) 3 }]. 42,43
We also report the reactivity toward XyNC or CO of one of
the products obtained by perfluoroalkylation of the coordinated
ethene. Whereas in the first case a ligand substitution reaction
took place, in the second the insertion of a CO molecule into
1288
Cp*)(CH 2 CH 2 R F )(μ-I)] 2 (R F = CF(CF 3 ) 2 (1a), CF(CF 3 )-
CF 2 CF 3 (1b), C(CF 3 ) 3 (1c)). Compounds 1a and 1b were
isolated as crystalline red solids containing small amounts
(10%) of [(η 5 -Cp*)IRh(μ-I) 2 Rh(η 5 -Cp*)(CH 2 CH 2 R F )] (2a,
2b, respectively). In the case of 1c, a greater amount of the
mixed iodide-bridged complex (2c), HC(CF 3 ) 3 , and small
amounts of unidentified compounds were also formed. The
identity of complexes 1 was established on the basis of (1)
their 1 Hand 19 F NMR data, (2) the characterization of the
products of their reactions with various phosphines (see
below), and (3) the X-ray structures of 1a and 1b. In addition,
the elemental analyses of samples of 1a or 1b containing 10%
(determined by 1 HNMR)of2a or 2b, respectively,agree
with the calculated values, supporting the formulation of both
components.
Complex 1a or 1b decomposes in solution at room
temperature over several days to give mainly 2a or 2b, together
with minor quantities of [Rh(η 5 -Cp*)I(μ-I)] 2 and other
products that could not be identified. Hence, the presence
of small amounts of 2a or 2b could be attributed to
decomposition of 1a or 1b during the reaction time. In
contrast, the larger amounts of 2c and other products detected
in the reaction of [Rh(η 5 -Cp*)(η 2 -C 2 H 4 ) 2 ] with IC(CF 3 ) 3
cannot be attributed solely to decomposition of 1c and are
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Organometallics
probably formed through an alternative reaction path (see
Mechanistic Studies).
The crystal structures of 1a and 1b (Figures 1 and 2) show
the presence of iodo-bridged dimers with the pairs of η 5 -Cp*
Figure 1. Molecular structure of 1a (50% thermal ellipsoids). Selected
bond lengths (Å) and angles (deg): Rh(1)−CNT1 (CNT1 = centroid
of C1−5) 1.8250(19), Rh(1)−C(11) 2.111(4), Rh(1)−I(1)
2.7198(4), Rh(1)−I(2) 2.7077(4), Rh(2)−CNT2 (CNT2 = centroid
of C21−25) 1.8300(18), Rh(2)−C(31) 2.108(4), Rh(2)−I(1)
2.7100(4), Rh(2)−I(2) 2.6987(4), I(1)−Rh(1)−I(2) 87.229(11),
C(11)−Rh(1)−I(1) 87.19(10), C(11)−Rh(1)−I(2) 88.35(10),
C(31)−Rh(2)−I(2) 87.94(11), C(31)−Rh(2)−I(1) 85.90(10).
Figure 2. Molecular structure of 1b (50% thermal ellipsoids). Selected
bond lengths (Å) and angles (deg): Rh(1)−CNT1 (CNT1 = centroid
of C1−5) 1.820(3), Rh(1)−C(11) 2.111(6), Rh(1)−I(1) 2.7060(6),
Rh(1)−I(1A) 2.7134(6), C(11)−Rh(1)−I(1) 89.44(17), C(11)−
Rh(1)−I(1A) 88.87(17), I(1)−Rh(1)−I(1A) 86.513(18), Rh(1)−
I(1)−Rh(1A) 93.487(18).
and C 2 H 4 R F ligands necessarily mutually trans. This arrangement
is usually adopted by halide-bridged pentamethylcyclopentadienyl
complexes of Rh or Ir in order to reduce steric
hindrance. 39,47−50 For the same reason, the CH 2 CH 2 R F chains
are extended away from the metal. Bond distances and angles in
the coordination sphere are very similar for both complexes.
Article
In 1b, because of the presence of two chiral centers (at the
perfluoro-sec-butyl groups), two diastereomers are possible: the
racemic pair (with RR or SS configuration) and the meso
diastereomer (with RS configuration). However, in the single
crystal used for the X-ray structure determination only the meso
isomer was present. Indeed, the molecule of 1b is
centrosymmetric, whereas in 1a both CH 2 CH 2 CF(CF 3 ) 2
groups point to the same side of the molecule (as viewed
down the Rh−Rh axis) and the bond distances and angles are
slightly different for both metal fragments.
In the 1 H NMR spectra of 1a−c the methylene protons
appear as second-order multiplets around 3 ppm. The 19 FNMR
spectrum of 1a displays a doublet and a multiplet, corresponding
to the CF 3 and CF groups, respectively. The CF(CF 3 )CF 2 CF 3
group of 1b gives five signals, corresponding to the CF, the
diastereotopic CF 2 fluorines, and the CF 3 groups. The identity
of complexes 2 in their mixtures with 1 was established on the
basis of their 1 H and 19 F NMR signals. Thus, the 1 H spectra
show signals corresponding to two different η 5 -Cp* groups and
a complex multiplet around 3 ppm for the methylene protons,
and the 19 F spectra display a set of signals at chemical shift
values very close to those of 1.
Although two diastereomers are expected for 1b, only one set
of signals was observed in its 1 H and 19 F NMR spectra, even at
low temperature and in a high-field spectrometer (−80 °C,
600 MHz). As the selective formation of one diastereomer of
1b is unlikely, this could be the result of both isomers having
almost identical 1 H and 19 F NMR spectra. 51
NMR measurements on samples of 1a or 1b (containing
small amounts of 2a or 2b, respectively) treated with 1 equiv of
[Rh(η 5 -Cp*)I(μ-I)] 2 revealed that compounds 1, 2, and
[Rh(η 5 -Cp*)I(μ-I)] 2 are in equilibrium, whereby complexes 2
are the major components. This process is slow on the NMR
time scale at room temperature, but at about 80 °C the Cp*
signals of the three compounds coalesce into a unique signal in
the 1 H NMR spectrum (D 8 -toluene). This could be explained
by an exchange process involving cleavage and restoration of
the iodide bridges with combination of the resulting fragments.
[Rh(η 5 -Cp*)(η 2 -C 2 H 4 ) 2 ] reacted neither in C 6 D 6 solution
with I n C 4 F 9 ,IC 6 F 5 , or ICFCF 2 at room temperature nor on
heating at 50 °C(I n C 4 F 9 )orat60°C (IC 6 F 5 or ICFCF 2 ) for
several hours. Heating at higher temperatures led to mixtures of
products that were not identified. In agreement with previously
reported results, the reaction of [Rh(η 5 -Cp*)(η 2 -C 2 H 4 ) 2 ] and
ICF 2 C 6 F 5 was sluggish, and, after 21 h at room temperature,
most starting material remained unreacted. 39
Bridge-Cleavage Reactions. The reactions of the mixtures
of complexes 1 + 2 with PMe 3 , PPh 3 ,orP i Pr 3 led to
mononuclear complexes of the type [Rh(η 5 -Cp*)-
(CH 2 CH 2 R F )I(PR 3 )] (R F = CF(CF 3 ) 2 , R = Me (3a), Ph
(3a′), i Pr (3a″); R F = CF(CF 3 )CF 2 CF 3 ,R=Me(3b), Ph (3b′);
R F = C(CF 3 ) 3 ,R=Me(3c); Scheme 2), which were isolated
with 50−82% yields after separation of the byproducts [Rh(η 5 -
Cp*)I 2 (PR 3 )] by crystallization or chromatography. Complexes
3b and 3b′ were isolated as mixtures of two diastereomers
arising from the presence of two stereogenic centers in the
molecule, one at the perfluoro-sec-butyl group and another at
the Rh atom. The diastereomeric ratios were close to unity (1:1
and 1:1.1, respectively). This implies a negligible influence of
the configuration of the perfluoro-sec-butyl group on the side of
the attack of the phosphine to the metal, which is in turn
attributable to the long distance between the stereogenic
carbon atom and the metal.
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Reactions of [Rh(η 5 -Cp*)(η 2 -C 2 H 4 )(PR 3 )] (R = Me or Ph)
with Perfluoroiodocarbons. The reactions between in situ
generated [Rh(η 5 -Cp*)(η 2 -C 2 H 4 )(PR 3 )] and IR F (Scheme 3
Scheme 3
Article
products were tentatively identified in the reaction mixtures.
Significant amounts of HR F were also formed in the reactions
leading to 4g and 4h.
The reaction of [Rh(η 5 -Cp)(η 2 -C 2 H 4 )(PMe 3 )] with I n C 4 F 9
(Scheme 4) gave [Rh(η 5 -Cp)( n C 4 F 9 )I(PMe 3 )] (5), which was
Scheme 4
and Table 1) led, in general, to mixtures containing the ethene
perfluoroalkylation or perfluoroarylation products (3), the
oxidative addition products (4), complexes [Rh(η 5 -Cp*)-
I 2 (PR 3 )] (R = Me or Ph), and other products that could not
be separated and identified. The nature of the main reaction
product depends on R and R F . Thus, addition to ethene prevails
in the reactions of [Rh(η 5 -Cp*)(η 2 -C 2 H 4 )(PMe 3 )] with
ICF(CF 3 ) 2 , IC(CF 3 ) 3 , or IC 6 F 5 and in the reactions of
[Rh(η 5 -Cp*)(η 2 -C 2 H 4 )(PPh 3 )] with ICF(CF 3 ) 2 or ICF 2 C 6 F 5
to give complexes 3a, 3c, 3d, 3a′, and 3e′ (Scheme 3),
respectively, which were isolated in 12−80% yields (Table 1).
The corresponding oxidative addition products were not
detected in these reactions except for ICF 2 C 6 F 5 , where a
minor amount was tentatively identified in the NMR spectra
of the reaction mixture. In contrast, oxidative addition is
dominant for the reactions of [Rh(η 5 -Cp*)(η 2 -C 2 H 4 )(PMe 3 )]
with ICF 2 C 6 F 5 ,I n C 3 F 7 , and I n C 4 F 9 , which gave the previously
reported [Rh(η 5 -Cp*)(R F )I(PMe 3 )] (R F =CF 2 C 6 F 5 (4e) 22 or
n C 3 F 7 (4f) 21 ) and the new compound [Rh(η 5 -Cp*)( n C 4 F 9 )I-
(PMe 3 )] (4g). Complexes 4e and 4g were isolated, but 4f was
identified in the reaction mixture by comparison of its NMR
signals with those reported. Finally, the reaction of [Rh(η 5 -
Cp*)(η 2 -C 2 H 4 )(PMe 3 )] with ICFCF 2 gave [Rh(η 5 -Cp*)-
I 2 (PMe 3 )] as the main product, and the oxidative addition
product 4h was isolated in low yield by chromatography. In the
reactions leading to 4e−h, only minor amounts of the
corresponding ethene perfluoro(alkylation or vinylation)
isolated and characterized. In contrast, the reactions of the
same complex with ICF(CF 3 ) 2 , IC 6 F 5 , or ICFCF 2 led to
intractable mixtures containing large amounts of [Rh(η 5 -Cp)-
I 2 (PMe 3 )].
The obtained complexes gave the expected signals in their
NMR spectra. Because of the presence of a stereogenic center
at the metal, the four methylene protons of complexes 3 appear
inequivalent in their 1 H NMR spectra. For the same reason,
two signals are observed for the CF 3 groups of 3a, 3a′, and 3a″
and for the CF 2 fluorines of 3b and 3b′. The 31 P{ 1 H} spectra of
complexes 3 showed a doublet as a consequence of the coupling
with 103 Rh. In contrast, the oxidative addition complexes
gave doublets of multiplets (4g and 5) or a doublet of doublets
(4h) because of the coupling of 31 P with 103 Rh and with the 19 F
nuclei of the rhodium-bound n C 4 F 9 or CFCF 2 groups,
respectively. The signals of 3b and 3b′ were duplicated because
of the presence of two diastereomers (see above).
The crystal structures of 3c and 4g were determined by
single-crystal X-ray diffraction (Figures 3 and 4). In both
Table 1. Composition (%) of the Mixture of Products of the
Reaction [Rh(η 5 -Cp*)(η 2 -C 2 H 4 )(PR 3 )] + IR F
a
R F
R
attack on
ethene
oxidative
addition
[Rh(η 5 -Cp*)
I 2 (PR 3 )]
CF(CF 3 ) 2 Me 51 (3a) 0 5
CF(CF 3 ) 2 Ph 91 (3a′) 0 5
C(CF 3 ) 3 Me 100 (3c) 0 0
C 6 F 5 Me 57 (3d) 0 4
CF 2 C 6 F 5 Me 0 64 (4e) 15
CF 2 C 6 F 5 Ph 40 (3e′) ≤10 b 31
n C 3 F 7 Me ≤7 b 40 (4f) 27
n C 4 F 9 Me ≤5 b 40 (4g) 24
CFCF 2 Me ≤7 b 19 (4h) 40
a Estimated by integration of the 31 P{ 1 H} NMR spectrum of the
reaction mixture (error ±5%).
Tentatively identified in the NMR
spectra of the mixture.
Figure 3. Molecular structure of 3c (50% thermal ellipsoids). Selected
bond lengths (Å) and angles (deg): Rh(1)−CNT (CNT = centroid of
C1−5) 1.8789(16), Rh(1)−C(11) 2.120(3), Rh(1)−P(1) 2.2594(9),
Rh(1)−I(1) 2.6989(4), C(11)−Rh(1)−P(1) 85.31(10), C(11)−
Rh(1)−I(1) 96.26(9), P(1)−Rh(1)−I(1) 89.02(3).
molecules, the fluorinated alkyl group is extended away from
the metal in order to reduce steric repulsions with the η 5 -Cp*
and PMe 3 ligands. The Rh−CH 2 distance in 3c (2.120(3) Å) is
not significantly different from those of 1a (2.111(4) and
2.108(4) Å) or 1b (2.111(6) Å). The terminal Rh−I bond of
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Article
Information) also indicated the presence of the anions H 2 F 3 − ,
HF 2 − , and SiF 6 2− , the latter probably being produced by F −
attack on the NMR tube glass (see below). 53−55
Reactions of 3a′ with AgOTf and XyNC or CO. The
reaction of 3a′ with AgOTf and XyNC gave the cationic
derivative [Rh(η 5 -Cp*){CH 2 CH 2 CF(CF 3 ) 2 }(PPh 3 )(CNXy)]-
OTf (6) (Scheme 6). In contrast, the analogous reaction of
Scheme 6
Figure 4. Molecular structure of 4g (50% thermal ellipsoids). Selected
bond lengths (Å) and angles (deg): Rh(1)−CNT (CNT = centroid of
C1−5) 1.8872(8), Rh(1)−P(1) 2.2967(5), Rh(1)−I(1) 2.68611(19),
Rh(1)−C(11) 2.0716(19), P(1)−Rh(1)−I(1) 88.673(13), C(11)−
Rh(1)−I(1) 89.71(5), C(11)−Rh(1)−P(1) 92.48(5), F(1)−C(11)−
Rh(1) 108.80(11), F(2)−C(11)−Rh(1) 116.91(12), F(2)−C(11)−
F(1) 103.06(14).
3c (Rh−I: 2.6989(4) Å) is slightly shorter than the bridging
Rh−I bonds of 1a and 1b (Rh−I: 2.6987(4)−2.7198(4) Å).
The Rh−CNT (CNT = centroid of the η 5 -Cp* ring) distance is
longer in 3c (1.8789(16) Å) and 4g (1.8872(8) Å) than in 1a
(1.8250(19) and 1.8300(18) Å) or 1b (1.820(3) Å), suggesting
that the steric repulsions between the η 5 -Cp* and PMe 3 ligands
could be responsible for these differences. The Rh−CNT, Rh−P,
and Rh−C bond distances of 4g are not significantly different
from the values reported for [Rh(η 5 -Cp*)Cl( n C 3 F 7 )(PMe 3 )]. 52
The reaction of [Rh(η 5 -Cp*)(η 2 -C 2 H 4 )(PR 3 )] with ICF-
(CF 3 )CF 2 CF 3 (Scheme 5) deserves special consideration, since
Scheme 5
3a′ with CO led to complex [Rh(η 5 -Cp*){CH 2 CH 2 CF(CF 3 ) 2 }-
(PPh 3 )(CO)]OTf (7), which resulted from insertion of a
molecule of CO into the Rh−CH 2 bond and coordination of
another CO molecule to the metal.
Compounds 6 and 7 gave the expected signals in their NMR
spectra. The IR spectrum of the isonitrile complex 6 showed a
band at 2133 cm −1 corresponding to the ν(CN) mode. The
IR spectra of the carbonyl complex 7 displayed a band at 2043
cm −1 corresponding to the ν(CO) mode and another at
1682 cm −1 corresponding to the ν(CO) mode.
The crystal structure of 7 was determined by single-crystal
X-ray diffraction (Figure 5). The Rh−C carbonyl and CO
no oxidative addition product and only traces of the ethene
perfluoroalkylation product were detected in the NMR spectra
of the reaction mixture (C 6 D 6 ). Instead, the main reaction
products were cis-octafluoro-2-butene, trans-octafluoro-2-
butene, [Rh(η 5 -Cp*)I 2 (PMe 3 )], and a crystalline red precipitate.
The ESI-MS spectrum of this precipitate indicated that it was a
salt of the cation [Rh(η 5 -Cp*)I(PMe 3 ) 2 ] + , which was
confirmed by comparing its 1 H and 31 P{ 1 H} NMR spectra
with those of the reported [Rh(η 5 -Cp*)I(PMe 3 ) 2 ]PF 6 . 37
In addition, the 1 H and 19 F NMR spectra of the salt (see
Experimental Section and Figure S1 of the Supporting
Figure 5. Molecular structure of 7 (50% thermal ellipsoids). Selected
bond lengths (Å) and angles (deg): Rh(1)−CNT (CNT = centroid of
C1−5) 1.9096(13), Rh(1)−C(11) 1.898(3), Rh(1)−C(12) 2.083(3),
Rh(1)−P(1) 2.3380(7), C(11)−O(1) 1.130(4), C(12)−O(2)
1.200(4), C(11)−Rh(1)−C(12) 95.00(12), C(11)−Rh(1)−P(1)
91.99(9), C(12)−Rh(1)−P(1) 87.15(8).
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(in D -toluene), or IC F (in C D ) were dramatically affected
distances (1.898(3) and 1.130(4) Å) fall in the range of values
found for Rh(III) carbonyl complexes containing the η 5 -Cp*
ligand (1.800−2.041 and 1.040−1.149 Å, respectively). 56 The
Rh−C acyl distance (2.083(3) Å) is slightly longer than those
observed in other Rh(III) acyl complexes containing the η 5 -Cp*
ligand (2.010−2.071 Å).
Mechanistic Studies. It is interesting to trace a parallelism
between the reactions observed and the reaction of [Rh(η 5 -Cp*)-
(η 2 -C 2 H 4 )(PMe 3 )] with MeI, which led to [Rh(η 5 -Cp*)(η 2 -C 2 H 4 )-
(Me)(PMe 3 )]I through nucleophilic attack of the metal center
at the positively charged carbon atom. 37 Substitution of the
coordinated ethene by iodide finally gives [Rh(η 5 -Cp*)I(Me)-
(PMe 3 )]. The iodine-bound carbon of a perfluoroalkyl iodide
also bears a high positive charge, but it is sterically and electrostatically
shielded from nucleophilic attack by the negatively
charged fluorine substituents, especially in secondary and tertiary
perfluoroalkyl iodides. 57,58 In addition, the electron-withdrawing
character of the perfluoroalkyl group makes the iodine atom
electrophilic, allowing nucleophilic attack and subsequent release
of a perfluoroalkyl anion. 57−60 Such anions have been trapped by
Hughes and co-workers in the reactions of Rh(I), 29 Mo(II), 42,43
W(II), 42,43 or Pt(II) 61 complexes with perfluoroalkyl iodides. In a
benchmark study, 42 the same authors reported that the ethene
complexes [M(η 5 -Cp) 2 (η 2 -C 2 H 4 )] (M = Mo or W) react with
IC(CF 3 ) 3 to give [M(η 5 -Cp) 2 I{CH 2 CH 2 C(CF 3 ) 3 }] via nucleophilic
attack of the metal at the iodine, followed by addition of
the generated C(CF 3 ) − 3 anion to the coordinated ethene. 42,43
Alternatively, the possibility of a radical mechanism should
be considered, since perfluoroalkyl iodides are able to react with
electron donors by single electron transfer to give I − and an R F·
radical. 11,62 Considering these precedents, we attempted to find
experimental evidence for the intermediacy of R F· radicals or
R − F anions in the ethene perfluoroalkylation reactions.
As D 8 -toluene is expected to react with free R F· radicals to
give a D 7 -benzyl radical and DR F , 61 some representative
reactions were conducted in this solvent. However, no DR F
was detected by NMR spectroscopy in any experiment.
As perfluoroalkyl radicals easily add to olefins, 11,63,64 the
reactions between [Rh(η 5 -Cp*)(η 2 -C 2 H 4 )(PMe 3 )] and ICF-
(CF 3 ) 2 were performed in the presence of a 4-fold excess of
norbornene. However, the outcome of the reaction was not
appreciably altered, and no significant amounts of norbornene
perfluoroalkylation products were detected.
In addition, the reactions of [Rh(η 5 -Cp*)(η 2 -C 2 H 4 )(PMe 3 )]
or [Rh(η 5 -Cp*)(η 2 -C 2 H 4 ) 2 ] with ICF(CF 3 ) 2 were carried out
in the presence of the radical trap (2,2,6,6-tetramethylpiperidin-
1-yl)oxyl (TEMPO), using C 6 D 6 as solvent. While in the first
case the result of the reaction was essentially the same as in the
absence of the radical trap, in the second case most of the
starting materials remained unreacted after 16 h. As no radicaltrapping
products were detected, the reaction inhibition is
tentatively attributed to competitive formation of a halogenbonded
adduct between TEMPO and the perfluoroalkyl
iodide. 60 The formation of this adduct did not compete effectively
with the rapid reaction between complex [Rh(η 5 -Cp*)-
(η 2 -C 2 H 4 )(PMe 3 )] and ICF(CF 3 ) 2 .
We also attempted to trap radical or carbanionic
intermediates by carrying out the reactions in the presence of
CH 3 OD as previously reported. 29,42,61,65 In these experiments,
R F· radicals should preferentially cleave the weaker C−H
bond 66 to give HR F , whereas R − F anions should abstract a D +
cation to give DR F . Thus, the reactions of [Rh(η 5 -Cp*)-
(η 2 -C 2 H 4 )(PMe 3 )] with ICF(CF 3 ) 2 (in D 8 -toluene), IC(CF 3 ) 3
8 6 5 6 6
by the presence of CH 3 OD (1.5−2.5 equiv). Under these conditions,
the formation of complex 3a, 3c, or3d was inhibited or
severely reduced, DR F being the main fluoroorganic product.
Moreover, significant amounts of DC(CF 3 ) 3 or DC 6 F 5 were
detected when the reactions between [Rh(η 5 -Cp*)(η 2 -C 2 H 4 )-
(PMe 3 )] and IC(CF 3 ) 3 or IC 6 F 5 were run in C 6 D 6 saturated
with D 2 O. Minor amounts of HR F were also detected in all these
experiments, even in the absence of CH 3 OD, which might be
attributed to carbanion protonation by residual water or to the
contribution of a minor reaction pathway involving perfluoroalkyl
radicals. 67 The reactions of [Rh(η 5 -Cp*)(η 2 -C 2 H 4 ) 2 ]with
ICF(CF 3 ) 2 or ICF(CF 3 )CF 2 CF 3 in C 6 D 6 were not significantly
affected when they were carried out in the presence of CH 3 OD or
in D 2 O-saturated solvent. In contrast, the analogous reactions
involving IC(CF 3 ) 3 gave considerable amounts of DC(CF 3 ) 3 .
Evidence for both radical and anions was obtained in the
reaction of [Rh(η 5 -Cp*)(η 2 -C 2 H 4 )(PMe 3 )] with I n C 4 F 9 in C 6 D 6 .
Thus, the formation of the oxidative addition product 4g was
partially inhibited by carrying out the reaction in the presence of
norbornene or TEMPO (2 equiv), and significant amounts of
D n C 4 F 9 were observed by carrying it out in the presence of
CH 3 OD (2.5 equiv). This suggests that, in this case, both ionic
and radical pathways should contribute significantly to the overall
reaction mechanism.
Finally, the detection of cis- and trans-octafluoro-2-butene in
the reaction of [Rh(η 5 -Cp*)(η 2 -C 2 H 4 )(PMe 3 )] with ICF(CF 3 )-
CF 2 CF 3 is evidence for the generation of the CF 3 CF 2 (CF 3 )CF −
anion, which decomposes by elimination of F − to give the alkenes.
The released fluoride anion could trap a proton from residual
moisture or react with glass to form the H n F − n+1 and SiF 2− 6 anions
of the isolated salt. No perfluoroalkenes were detected in other
reaction mixtures examined by 19 F NMR spectroscopy.
On the basis of these results, we propose (Scheme 7) that
ethene perfluoro(alkylation or arylation) could occur by
Scheme 7
nucleophilic attack of the metal on the iodine atom to generate
the ionic intermediate A, which could undergo addition of the
R − F anion on the coordinated ethene to give complexes 3.
When L = C 2 H 4 , dinuclear species 1 could be formed by loss of
ethene and dimerization, although evidence for the formation
of R − F anions was found only in the case of 1c.
Compounds [Rh(η 5 -Cp*)I 2 (PR 3 )] and other unidentified byproducts
observed in the reactions of [Rh(η 5 -Cp*)(η 2 -C 2 H 4 )-
(PMe 3 )] with IR F could result from the evolution of intermediate A
after the dissociation of the ion pair and the destruction of the
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Organometallics
perfluoroalkyl anion by decomposition or by reaction with another
molecule. In particular, protonation by residual water would give
HR F , which was observed in the reactions leading to 4g or 4h. A
similar process could explain the formation of HC(CF 3 ) 3 and 2c in
the reaction of [Rh(η 5 -Cp*)(η 2 -C 2 H 4 ) 2 ] with IC(CF 3 ) 3 .
Finally, we tried to prepare a salt containing the cation of
intermediate A by reaction of [Rh(η 5 -Cp*)(η 2 -C 2 H 4 )(PMe 3 )]
with the iodinating agent [I(py) 2 ]BF 4 . However, substitution of
ethene by pyridine (py) took place in addition to iodination, to
give [Rh(η 5 -Cp*)I(py)(PMe 3 )]BF 4 (8), which was also obtained
by reaction of [Rh(η 5 -Cp*)I 2 (PMe 3 )] with AgBF 4 and pyridine.
The crystal structure of 8 was determined by single-crystal X-ray
diffraction (Figure 6).
Figure 6. Molecular structure (30% thermal ellipsoids) of the cation of
the salt [Rh(η 5 -Cp*)I(C 6 H 5 N)(PMe 3 )]BF 4 (8). Selected bond
lengths (Å) and angles (deg): Rh−CNT (CNT = centroid of C1−
5) 1.825, Rh−N(11) 2.1271(19), Rh−P 2.3160(7), Rh−I 2.6989(2),
N(11)−Rh−I 91.80(5), P−Rh−I 87.64(2), N(11)−Rh−P 90.66(6).
■ CONCLUDING REMARKS
Selective ethene perfluoroalkylation takes place in the reaction
of [Rh(η 5 -Cp*)(η 2 -C 2 H 4 ) 2 ] with secondary or tertiary
perfluoroalkyl iodides. In contrast, the course of the reactions
of [Rh(η 5 -Cp*)(η 2 -C 2 H 4 )(PMe 3 )] with perfluorinated iodides
depends on the fluoroorganic iodide used. Thus, ICF(CF 3 ) 2 ,
IC(CF 3 ) 3 , and IC 6 F 5 selectively attack at the ethene, while the
reactions with primary perfluoroalkyl iodides and ICF 2 C 6 F 5 are
less selective and proceed preferentially through oxidative
addition. Attack at the ethene also prevails in the reaction of
[Rh(η 5 -Cp*)(η 2 -C 2 H 4 )(PPh 3 )] with ICF(CF 3 ) 2 or ICF 2 C 6 F 5 .
Evidence for the intermediacy of R − F anions in the ethene
perfluoroalkylation or perfluoroarylation reactions points to a
mechanism where a cationic Rh(III) intermediate is formed by
the nucleophilic attack of the metal center at the iodine atom of
the perfluororganic iodide.
The reported reactions are rare examples of perfluoroalkylation
or perfluoroarylation of a coordinated alkene and represent
a first step toward nonradical rhodium-catalyzed perfluoroalkylation
of olefins avoiding the formation of perfluoroalkyl metal
intermediates. Studies aimed at the development of a rhodiummediated
or -catalyzed olefin perfluoroalkylation reaction are in
progress.
1293
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Article
EXPERIMENTAL SECTION
General Considerations. Complexes [Rh(η 5 -Cp*)(η 2 -C 2 H 4 ) 2 ] 34
and [Rh(η 5 -Cp)(η 2 -C 2 H 4 )(PMe 3 )] 35 were prepared as previously
reported. Solutions of complexes [Rh(η 5 -Cp*)(η 2 -C 2 H 4 )(PR 3 )]
(R = Me, 37 Ph 68 )werepreparedbyheatingasolutionof[Rh(η 5 -Cp*)-
(η 2 -C 2 H 4 ) 2 ]andPMe 3 or PPh 3 at 120 °C in a Carius tube for 24 or 3.5 h,
respectively. Other reagents were obtained from commercial sources
and used without further purification: PMe 3 (1 M solution in toluene),
IC 6 F 5 ,I n C 4 F 9 ,I n C 3 F 7 , ICF 2 C 6 F 5 , [I(py) 2 ]BF 4 (Aldrich), ICF(CF 3 ) 2
(Acros Organics), ICFCF 2 (ABCR). The reactions were carried out
under an N 2 atmosphere using standard Schlenk techniques. Test
reactions were performed in screw-cap NMR tubes equipped with a
PTFE-covered rubber septum. Toluene and n-pentane were degassed
and dried using a Pure Solv MD-5 solvent purification system from
Innovative Technology, Inc. D 8 -Toluene was deoxygenated by four
freeze−pump−thaw cycles, and C 6 D 6 was distilled over CaH 2 . Both
solvents were stored under nitrogen over 4 Å molecular sieves.
Infrared spectra were recorded in the range 4000−200 cm −1 on a
Perkin-Elmer 16F PC FT-IR spectrometer with Nujol mulls between
polyethylene sheets. C, H, N, S analyses were carried out with Carlo
Erba 1108 and LECO CHS-932 microanalyzers. NMR spectra were
measured on Bruker Avance 200, 300, and 400 instruments. 1 H
chemical shifts were referenced to residual C 6 D 5 H (7.15 ppm),
C 6 D 5 CD 2 H (2.09 ppm), CHDCl 2 (5.29 ppm), or CHCl 3 (7.26 ppm).
13 C{ 1 H} spectra were referenced to C 6 D 6 (128.0 ppm), CDCl 3
(77.0 ppm), or CD 2 Cl 2 (53.8 ppm). 19 For 31 P{ 1 H} NMR spectra
were referenced to external CFCl 3 or H 3 PO 4 (0 ppm). The temperature
values in NMR experiments were not corrected. ESI-MS and
HR-MS spectra were measured on Agilent 5973 and 6620 spectrometers,
respectively. A solution of NH 4 (HCO 2 ) (5 mM) and HCO 2 H
(1%) in MeOH/H 2 O (75:25) was used as mobile phase unless otherwise
stated. Melting points were determined on a Reichert apparatus
in an air atmosphere.
[Rh(η 5 -Cp*){CH 2 CH 2 CF(CF 3 ) 2 }(μ-I)] 2 (1a) and [(η 5 -Cp*)IRh(μ-I) 2 -
Rh(η 5 -Cp*){CH 2 CH 2 CF(CF 3 ) 2 }] (2a). ICF(CF 3 ) 2 (100 μL, 0.70 mmol)
was added to a solution of [Rh(η 5 -Cp*)(η 2 -C 2 H 4 ) 2 ] (186 mg,
0.63 mmol) in n-pentane (3 mL). After stirring for 18 h at room
temperature a red, microcrystalline solid precipitated, which was filtered,
washed with n-pentane (2 mL), and dried under vacuum (270 mg,
76%). Mp: 258−261 °C (dec). The isolated product contained 10%
of [(η 5 -Cp*)IRh(μ-I) 2 Rh(η 5 -Cp*){CH 2 CH 2 CF(CF 3 ) 2 }] as determined
by integration of the 1 H NMR spectrum. Anal. Calcd for (C 30 H 38 F 14 I 2 -
Rh 2 ) 0.9 (C 25 H 34 F 7 I 3 Rh 2 ) 0.1 : C, 31.72; H, 3.39. Found: C, 31.68; H, 3.66.
1a: 1 H NMR (300.1 MHz, CDCl 3 ): δ 2.85−2.58 (m, 8 H, CH 2 ), 1.67
(s, 30 H, C 5 Me 5 ); (300.1 MHz, C 6 D 6 ) δ 3.15−2.90 (m, 8 H, CH 2 ), 1.37
(s,30H,C 5 Me 5 ). 13 C{ 1 H} NMR (75.5 MHz, CD 2 Cl 2 ): δ 122.0 (dq,
1 J CF = 288.6 Hz, 2 J CF =28.7Hz,CF 3 ), 95.2 (d, 1 J RhC = 6.6 Hz, C 5 Me 5 ),
38.1 (d, 2 J FC =20.8Hz,CH 2 CF), 9.5 (s, C 5 Me 5 ), 5.9 (d, 1 J RhC =24.9Hz,
RhCH 2 ). The signal corresponding to the CF carbon was not observed.
19 F NMR (282.4 MHz, C 6 D 6 ): δ −74.6 (d, 3 J FF = 7.6 Hz, 6 F, CF 3 ),
−181.7 (m, 1 F, CF). X-ray quality single crystals were obtained as
deuterobenzene monosolvate by slow evaporation of a C 6 D 6 solution.
2a: 1 H NMR (300.1 MHz, C 6 D 6 ): δ 3.03−2.88 (m, 4 H, CH 2 ), 1.53 (s,
15 H, C 5 Me 5 ), 1.46 (s, 15 H, C 5 Me 5 ). 19 F NMR (282.4 MHz, C 6 D 6 ): δ
−74.5 (d, 3 J FF = 7.5 Hz, 6 F, CF 3 ), −180.2 (m, 1 F, CF).
[Rh(η 5 -Cp*){CH 2 CH 2 CF(CF 3 )CF 2 CF 3 }(μ-I)] 2 (1b) and [(η 5 -Cp*)-
IRh(μ-I) 2 Rh(η 5 -Cp*){CH 2 CH 2 CF(CF 3 )CF 2 CF 3 }] (2b). These were
prepared in the same way as 1a + 2a, starting from [Rh(η 5 -Cp*)-
(η 2 -C 2 H 4 ) 2 ] (48 mg, 0.16 mmol) and ICF(CF 3 )CF 2 CF 3 (28 μL, 0.16
mmol) in n-pentane (3 mL). After stirring for 18 h, the reaction
mixture was stored at 4 °C for 3 days to give a red, crystalline solid.
The mother liquor was removed with a pipet in a ice−water bath, and
the solid was washed with cold (0 °C) n-pentane (3 × 1.5 mL) and
dried under vacuum (68 mg, 68%). Mp: 140 °C (dec). The isolated
product contained 10% of [(η 5 -Cp*)IRh(μ-I) 2 Rh(η 5 -Cp*)-
{CH 2 CH 2 CF(CF 3 )CF 2 CF 3 }] as determined by integration of the 1 H
NMR spectrum. Anal. Calcd for (C 32 H 38 F 18 I 2 Rh 2 ) 0.9 (C 26 H 34 F 9 I 3 Rh 2 ) 0.1 :
C, 31.11; H, 3.13. Found: C, 31.06; H, 3.08. 1b: 1 H NMR (400.9 MHz,
C 6 D 6 ): δ 3.19−2.93 (m, 8 H, CH 2 ), 1.39 (s, 30 H, C 5 Me 5 ). 13 C{ 1 H}
dx.doi.org/10.1021/om2009588 | Organometallics 2012, 31, 1287−1299

Organometallics
NMR (100.8 MHz, CD 2 Cl 2 ): δ 126.6−109.3 (several m, CF n ), 95.2
(d, 1 J RhC = 6.5 Hz, C 5 Me 5 ), 38.6 (d, 2 J FC = 21.6 Hz, RhCH 2 CH 2 ), 9.5
(s, C 5 Me 5 ), 6.2 (d, 1 J RhC = 24.6 Hz, RhCH 2 ). 19 F NMR (188.3 MHz,
C 6 D 6 ): δ −72.1 (br s, 3 F, CFCF 3 ), −79.7 (dq, 4 J FF = 5 J FF = 5.1 Hz, 3
F, CF 2 CF 3 ), −120.6 (m, 2 F, CF 2 ), −180.9 (br m, 1 F, CF). (+)ESI-
MS: m/z 731 ([Rh 2 (C 5 Me 5 ) 2 I 2 H] + ), 857 ([Rh 2 (C 5 Me 5 ) 2 I 3 ] + ), 977
([Rh 2 (C 5 Me 5 ) 2 I 2 (CH 2 CH 2 C 4 F 9 )] + ). X-ray quality single crystals were
obtained from an n-hexane solution at 4 °C. 2b: 1 H NMR (400.9
MHz, C 6 D 6 ): δ 3.08−2.91 (m, 4 H, CH 2 ), 1.53 (s, 15 H, C 5 Me 5 ), 1.48
(s, 15 H, C 5 Me 5 ). 19 F NMR (188.3 MHz, C 6 D 6 ): δ −72.3 (br s, 3 F,
CFCF 3 ), −79.7 (m, 3 F, CF 2 CF 3 ), −120.5 (m, 2 F, CF 2 ), −180.1
(br m, 1 F, CF).
[Rh(η 5 -Cp*){CH 2 CH 2 C(CF 3 ) 3 }(μ-I)] 2 (1c) and [(η 5 -Cp*)IRh(μ-I) 2 -
Rh(η 5 -Cp*){CH 2 CH 2 C(CF 3 ) 3 }] (2c). These were prepared in the same
way as 1a + 2a, starting from [Rh(η 5 -Cp*)(η 2 -C 2 H 4 ) 2 ] (111 mg, 0.38
mmol) and IC(CF 3 ) 3 (185, mg, 0.53 mmol) in n-pentane (4 mL). The
reaction mixture was evaporated to dryness to give a dark red residue
containing 1c, a similar number of equivalents of 2c, and several
unidentified minor products (the integration of the 1 H NMR spectrum
was not accurate because of signal overlap). Attempts to isolate 1c by
crystallization or column chromatography led to mixtures containing
both products. 1c: 1 H NMR (200.1 MHz, C 6 D 6 ): δ 3.25 (m, 4 H,
CH 2 ), 2.97 (m, 4 H, CH 2 ), 1.38 (s, 30 H, C 5 Me 5 ). 19 F NMR (188.3
MHz, C 6 D 6 ): δ −64.5 (s). 2c: 1 H NMR (200.1 MHz, C 6 D 6 ): δ 3.16−
2.90 (m, 4 H, CH 2 ), 1.52 (s, 15 H, C 5 Me 5 ), 1.49 (s, 15 H, C 5 Me 5 ). 19 F
NMR (188.3 MHz, C 6 D 6 ): δ −64.7 (s).
[Rh(η 5 -Cp*){CH 2 CH 2 CF(CF 3 ) 2 }I(PMe 3 )] (3a). Method A. A mixture
of [Rh(η 5 -Cp*)(η 2 -C 2 H 4 ) 2 ] (147 mg, 0.50 mmol) and PMe 3
(0.60 mmol) was heated in toluene (5 mL) at 120 °C for 24 h in a
Carius tube. The resulting solution of [Rh(η 5 -Cp*)(η 2 -C 2 H 4 )(PMe 3 )]
was cooled at room temperature, and then ICF(CF 3 ) 2 (74 μL,
0.50 mmol) was added. A color change from yellow to dark red took
place immediately. After stirring for 40 min, the volatiles were removed
under vacuum. The residue was extracted with Et 2 O (15 mL), and the
extract was chromatographed on a silica gel column using CH 2 Cl 2 as
eluent. The collected fraction (R f = 0.8) was evaporated to dryness to
give an orange, crystalline solid (151 mg, 47%).
Method B. ICF(CF 3 ) 2 (100 μL, 0.70 mmol) was added to a
solution of [Rh(η 5 -Cp*)(η 2 -C 2 H 4 ) 2 ] (200 mg, 0.68 mmol) in n-
pentane (5 mL), and the mixture was stirred for 15 h. The dark red
suspension was evaporated to dryness under vacuum, and the residue
was dissolved in THF (5 mL). PMe 3 (0.74 mmol) was added to the
solution, and the mixture was stirred for 3 h. Then, the volatiles were
removed under vacuum, and the resulting residue was purified by
chromatography as mentioned above (215 mg, 50%). Mp: 91−93 °C.
Anal. Calcd for C 18 H 28 F 7 IPRh: C, 33.88; H, 4.42. Found: C, 34.02; H,
4.74. 1 H NMR (400.9 MHz, C 6 D 6 ): δ 3.03 (m, 1 H, Rh−CH 2 −CH 2 ),
2.26 (m, 1 H, Rh−CH 2 −CH 2 ), 1.70 (m, 1 H, Rh−CH 2 −CH 2 ), 1.50
(m, 1 H, Rh−CH 2 −CH 2 ), 1.46 (d, 4 J PH = 2.9 Hz, 15 H, C 5 Me 5 ), 1.15
(dd, 2 J PH = 9.8 Hz, 3 J RhH = 0.6 Hz, 9 H, PMe 3 ). 13 C{ 1 H} NMR (100.8
MHz, C 6 D 6 ): δ 122.2 (dq, 1 J CF = 287.0 Hz, 2 J CF = 29.0 Hz, CF 3 ), 98.2
(dd, 1 J RhC = 5.0 Hz, 2 J PC = 3.5 Hz, C 5 Me 5 ), 38.1 (dd, 2 J FC = 20.7 Hz,
3 J PC = 4.8 Hz, CH 2 CF), 17.1 (d, 1 J PC = 32.3 Hz, PMe 3 ), 9.7 (s, C 5 Me 5 ),
−0.6 (dd, 1 J RhC = 26.0 Hz, 2 J PC = 14.9 Hz, Rh−CH 2 −CH 2 ). The signal
corresponding to the CF carbon was not observed. 19 F NMR (188.3
MHz, C 6 D 6 ): δ −74.7 (dq, 3 J FF = 4 J FF = 8.3 Hz, 3 F, CF 3 ), −75.4 (dq,
3 J FF = 4 J FF = 8.3 Hz, 3 F, CF 3 ), −182.0 (m, 1 F, CF). 31 P{ 1 H} NMR
(162.3 MHz, C 6 D 6 ): δ 2.8 (d, 1 J RhP = 156.4 Hz).
[Rh(η 5 -Cp*){CH 2 CH 2 CF(CF 3 ) 2 }I(PPh 3 )] (3a′). Method A. [Rh-
(η 5 -Cp*)(η 2 -C 2 H 4 )(PPh 3 )] was generated in situ by heating a solution
of [Rh(η 5 -Cp*)(η 2 -C 2 H 4 ) 2 ] (151 mg, 0.51 mmol) and PPh 3 (162 mg,
0.62 mmol) in toluene (5 mL) at 120 °C for 3.5 h in a Carius tube.
After cooling to room temperature, ICF(CF 3 ) 2 (80 μL, 0.55 mmol)
was added to the resulting yellow solution, which changed color to
dark red. After stirring for 40 min, the volatiles were removed under
vacuum. The residue was extracted with Et 2 O, and the extract was
chromatographed on a silica gel column using Et 2 O/n-hexane (1:1) as
eluent. The collected orange fraction (R f = 0.6) was evaporated to
dryness to give an orange, crystalline solid (205 mg, 49%).
1294
Article
Method B. A solution of 1a + 2a (101 mg, 0.086 mmol of 1a) and
PPh 3 (52 mg, 0.20 mmol) in THF (5 mL) was stirred for 5 h. The
volatiles were removed under vacuum, and the resulting residue was
purified by column chromatography (see above) to give an orange,
crystalline solid (122 mg, 86%). Mp: 145−148 °C. Anal. Calcd for
C 33 H 34 F 7 IPRh: C, 48.08; H, 4.16. Found: C, 48.18; H, 4.24. 1 HNMR
(400.9 MHz, C 6 D 6 ): δ 7.72 (br m, 6 H, H2 of Ph), 6.99 (m, 9 H, H3
andH4ofPh),3.52(m,1H,Rh−CH 2 −CH 2 ), 2.38 (m, 1 H, Rh−
CH 2 −CH 2 ), 2.08 (m, 1 H, Rh−CH 2 −CH 2 ), 1.92 (m, 1 H, Rh−CH 2 −
CH 2 ), 1.32 (d, 4 J PH =2.8Hz,15H,C 5 Me 5 ). 13 C{ 1 H} NMR (75.5 MHz,
CDCl 3 ,50°C): δ 134.9 (br s, C2 of Ph), 133.0 (d, 1 J PC = 44.2 Hz, C1 of
Ph), 130.1 (s, C4 of Ph), 127.9 (d, 3 J PC = 9.9 Hz, C3 of Ph), 121.5 (dq,
1 J CF = 286.1 Hz, 2 J CF =28.6Hz,CF 3 ), 99.8 (dd, 1 J RhC = 4.6 Hz, 2 J PC =
3.3 Hz, C 5 Me 5 ), 38.8 (d, 2 J FC =20.4Hz,Rh−CH 2 −CH 2 ), 9.3 (s,
C 5 Me 5 ), 1.6 (dd, 1 J RhC =25.0Hz, 2 J PC =13.4Hz,Rh−CH 2 −CH 2 ). At
room temperature the aromatic region of the spectrum is more complex
because of slow rotation of the phosphine ligand on the NMR time
scale. 69 The signal corresponding to the CF carbon was not observed.
19 FNMR(188.3MHz,C 6 D 6 ): δ −74.1 (dq, 3 J FF = 4 J FF =8.5Hz,3F,
CF 3 ), −76.1 (dq, 3 J FF = 4 J FF =8.5Hz,3F,CF 3 ), −182.4 (m, 1 F, CF).
31 P{ 1 H} NMR (81.0 MHz, C 6 D 6 ): δ 41.6 (d, 1 J RhP = 161.2 Hz).
[Rh(η 5 -Cp*){CH 2 CH 2 CF(CF 3 ) 2 }I(P i Pr 3 )] (3a″). P i Pr 3 (35 μL, 0.18
mmol) was added to a solution of 1a + 2a (85 mg, 0.072 mmol of 1a)
in CH 2 Cl 2 (5 mL). The resulting solution was stirred for 13 h at room
temperature and evaporated to dryness. The residue was extracted
with n-pentane (15 mL), and the extract was filtered through Celite,
concentrated to ca. 2 mL, and stored at −32 °C for 4 h to give orange
crystals, which were washed with cold n-pentane (−30 °C, 3 × 1 mL)
and dried under vacuum (80 mg, 77%). Mp: 95−97 °C. Anal. Calcd
for C 24 H 40 F 7 IPRh: C, 39.91; H, 5.58. Found: C, 39.70; H, 5.60. 1 H
NMR (300.1 MHz, C 6 D 6 ): δ 3.65 (m, 1 H, Rh−CH 2 −CH 2 ), 2.35−
2.18 (m, 4 H, Rh−CH 2 −CH 2 + PCH), 2.08 (m, 1 H, Rh−CH 2 −
CH 2 ), 1.54−1.42 (m, 1 H, Rh−CH 2 −CH 2 ), 1.46 (d, 4 J PH = 2.3 Hz, 15
H, C 5 Me 5 ), 1.12 (dd, 2 J PH = 12.8 Hz, 3 J HH = 7.3 Hz, 3 H, CHMe), 1.04
(dd, 2 J PH = 12.6 Hz, 3 J HH = 7.2 Hz, 3 H, CHMe). 13 C{ 1 H} NMR
(100.8 MHz, C 6 D 6 ): δ 122.2 (dq, 1 J CF = 283.2 Hz, 2 J CF = 29.7 Hz,
CF 3 ), 99.8 (dd, 1 J RhC = 4.4 Hz, 2 J PC = 2.8 Hz, C 5 Me 5 ), 39.5 (d, 2 J FC =
20.5 Hz, Rh−CH 2 −CH 2 ), 27.9 (d, 1 J PC = 18.7 Hz, PCH), 21.0 (br s,
CHMe), 20.5 (d, 2 J PC = 1.1 Hz, CHMe), 10.2 (s, C 5 Me 5 ), −5.0 (dd,
1 J RhC = 26.4 Hz, 2 J PC = 14.7 Hz, Rh−CH 2 −CH 2 ). The signal corresponding
to the CF carbon was not observed. 19 F NMR (188.3 MHz,
C 6 D 6 ): δ −73.9 (dq, 3 J FF = 4 J FF = 8.5 Hz, 3 F, CF 3 ), −76.0 (dq, 3 J FF =
4 J FF = 8.9 Hz, 3 F, CF 3 ), −182.8 (m, 1 F, CF). 31 P{ 1 H} NMR (81.0
MHz, C 6 D 6 ): δ 42.9 (d, 1 J RhP = 153.0 Hz).
[Rh(η 5 -Cp*){CH 2 CH 2 CF(CF 3 )CF 2 CF 3 }I(PMe 3 )] (3b). A solution of
[Rh(η 5 -Cp*)(η 2 -C 2 H 4 ) 2 ] (70 mg, 0.24 mmol) in n-pentane (4 mL)
was treated with ICF(CF 3 )CF 2 CF 3 (40 μL, 0.24 mmol) at room
temperature. After stirring for 20 h at room temperature, PMe 3
(0.24 mmol) was added. The solution was stirred at room temperature
for 2 h and evaporated to dryness under vacuum. The residue was
extracted with n-pentane (15 mL). The extract was filtered, concentrated
under vacuum to ca. 2 mL, and stored at −32 °C for 24 h to give orange
crystals, which were washed with cold n-pentane (3 × 1 mL) and dried
under vacuum (87 mg, 53%). Mp: 100−102 °C. Anal. Calcd for
C 19 H 28 F 9 IPRh: C, 33.16; H, 4.10. Found: C, 33.19; H, 3.97. 1 H NMR
(300.1 MHz, CDCl 3 ): δ 2.59 (m, 1 H, Rh−CH 2 −CH 2 ), 2.08 (m, 1 H,
Rh−CH 2 −CH 2 ), 1.78 (d, 4 J PH = 2.8 Hz, 15 H, C 5 Me 5 ), 1.57 (m, 1 H,
Rh−CH 2 −CH 2 ), 1.54 (d, 2 J PH = 9.8 Hz, 9 H, PMe 3 ), 1.33 (m, 1 H,
Rh−CH 2 −CH 2 ); (300.1 MHz, C 6 D 6 ) δ 3.10 (m, 1 H, Rh−CH 2 −
CH 2 ), 2.30 (m, 1 H, Rh−CH 2 −CH 2 ), 1.73 (m, 1 H, Rh−CH 2 −CH 2 ),
1.50 (m, 1 H, Rh−CH 2 −CH 2 ), 1.44 (d, 4 J PH = 2.9 Hz, 15 H, C 5 Me 5 ),
1.114 (dd, 2 J PH = 9.8 Hz, 3 J RhH = 0.7 Hz, 9 H, PMe 3 ), 1.111 (dd, 2 J PH =
9.8 Hz, 3 J RhH = 0.7 Hz, 9 H, PMe 3 ). 13 C{ 1 H} NMR (75.5 MHz,
CDCl 3 ): δ 127.5−108.1 (several m, CF n ), 98.6 (dd, 1 J RhC = 3.2 Hz,
2 J PC = 1.5 Hz, C 5 Me 5 ), 98.5 (dd, 1 J RhC = 3.2 Hz, 2 J PC = 1.5 Hz, C 5 Me 5 ),
37.7 (d, 2 J FC = 24.0 Hz, Rh−CH 2 −CH 2 ), 37.4 (d, 2 J FC = 25.0 Hz, Rh−
CH 2 −CH 2 ), 17.5 (dd, 1 J PC = 32.4 Hz, 2 J RhC = 0.7 Hz, PMe 3 ), 17.4 (dd,
1 J PC = 32.5 Hz, 2 J RhC = 0.6 Hz, PMe 3 ), 10.01 (s, C 5 Me 5 ), 10.00 (s,
C 5 Me 5 ), 0.2 (dd, 1 J RhC = 25.6 Hz, 2 J PC = 14.7 Hz, Rh−CH 2 −CH 2 ).
dx.doi.org/10.1021/om2009588 | Organometallics 2012, 31, 1287−1299

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19 F NMR (282.4 MHz, C 6 D 6 ): δ −72.0 (s, 3 F, CF 3 CF, isomer A),
−72.7 (s, 3 F, CF 3 CF, isomer B), −79.5 (s, 3 F, CF 3 CF 2 , isomer A),
−79.7 (s, 3 F, CF 3 CF 2 , isomer B), −120.2 (AB doublet of multiplets,
2 J FF = 292.6 Hz, 1 F, CF 2 ,isomerA),−120.3 (m, 2 F, CF 2 ,isomerB),
−121.5 (AB doublet of multiplets, 2 J FF = 293.7 Hz, 1 F, CF 2 ,isomerA),
−180.8 (m, 1 F, CF, isomer A), −181.3 (m, 1 F, CF, isomer B).
31 P{ 1 H} NMR (162.3 MHz, C 6 D 6 ): δ 2.4 (d, 1 J RhP = 156.8 Hz), 2.2 (d,
1 J RhP = 156.8 Hz). (+)ESI-MS: m/z 347, 441 ([Rh(η 5 -Cp*)I(PMe 3 )] + ),
533, 711 ([M + Na] + );exactmasscalcdforC 19 H 28 F 9 INaPRh 710.9777,
found 710.9778, Δ =0.14ppm.
[Rh(η 5 -Cp*){CH 2 CH 2 CF(CF 3 )CF 2 CF 3 }I(PPh 3 )] (3b′). PPh 3 (19 mg,
0.072 mmol) was added to a solution of 1b + 2b (43 mg, 0.034 mmol
of 1b) inCH 2 Cl 2 (5 mL). The mixture was stirred for 20 h and
evaporated to dryness under vacuum. The residue was extracted with
n-pentane (5 mL). The extract was filtered, concentrated to ca. 1 mL,
and stored at −32 °C for 24 h. The orange-red crystals that formed
were separated from the mother liquor and washed twice with 1 mL
portions of cold n-pentane (46 mg, 77%). Mp: 131−133 °C. Anal.
Calcd for C 34 H 34 F 9 IPRh: C, 46.70; H, 3.92. Found: C, 46.62; H, 3.44.
1 H NMR (300.1 MHz, C 6 D 6 ): δ 7.73 (br m, 6 H, Ph), 7.00 (br m, 9 H,
Ph), 3.56 (m, 1 H, Rh−CH 2 −CH 2 ), 2.44 (m, 1 H, Rh−CH 2 −CH 2 ),
2.16−1.87 (m, 2 H, Rh−CH 2 −CH 2 ), 1.33 (s, 15 H, C 5 Me 5 ), 1.32 (d,
15 H, C 5 Me 5 ); (400.9 MHz, CDCl 3 ) δ 7.65−7.34 (br m, 15 H, Ph),
2.94 (m, 1 H, Rh−CH 2 −CH 2 ), 2.07 (m, 1 H, Rh−CH 2 −CH 2 ), 1.76−
1.65 (m, 2 H, Rh−CH 2 −CH 2 ), 1.51 (d, 4 J PH = 2.8 Hz, 15 H, C 5 Me 5 ),
1.49 (d, 4 J PH = 2.8 Hz, 15 H, C 5 Me 5 ). 13 C{ 1 H} NMR (100.8 MHz,
C 6 D 6 ): δ 137.5−132.5 (several br m, Ph), 130.1 (s, Ph), 127.9 (d,
J PC = 9.4 Hz, Ph), 126−108 (several overlapping m, CF n ), 99.7 (m,
C 5 Me 5 ), 95.5−92.4 (m, CF n ), 39.5 (d, 2 J FC = 20.9 Hz, Rh−CH 2 −
CH 2 ), 39.0 (d, 2 J FC = 21.2 Hz, Rh−CH 2 −CH 2 ), 9.4 (s, C 5 Me 5 ), 9.3 (s,
C 5 Me 5 ), 2.5 (dd, 1 J RhC = 24.9 Hz, 2 J PC = 13.0 Hz, Rh−CH 2 −CH 2 ), 2.4
(dd, 1 J RhC = 24.6 Hz, 2 J PC = 13.0 Hz, Rh−CH 2 −CH 2 ). 19 F NMR
(188.3 MHz, C 6 D 6 ): δ −72.5 (m, 3 F, CFCF 3 , isomer A), −74.4 (m, 3
F, CFCF 3 , isomer B), −80.1 (dq, 5 J FF = 4.6 Hz, 4 J FF = 9.0 Hz, 3 F,
CF 2 CF 3 , isomer A), −80.8 (dq, 5 J FF = 5.8 Hz, 4 J FF = 10.3 Hz, 3 F,
CF 2 CF 3 , isomer B), −120.3 (dq, 3 J FF = 6.7 Hz, 4 J FF = 9.2 Hz, 2 F, CF 2 ,
isomer B), −121.4 (dqd, 1 J FF = 292.2 Hz, 3 J FF = 6.9 Hz, 4 J FF = 11.5 Hz,
1F,CF 2 , isomer A), −123.2 (dqd, 1 J FF = 292.1 Hz, 3 J FF = 6.2 Hz,
4 J FF = 9.2 Hz, 1 F, CF 2 , isomer A), −182.0 (m, 1 F, CF, isomers A and
B). 31 P{ 1 H} NMR (162.3 MHz, CDCl 3 ): δ 40.5 (d, 1 J RhP = 161.8 Hz),
40.0 (d, 1 J RhP = 162.1 Hz). (+)ESI-MS: m/z 499 ([Rh(C 5 Me 4 CH 2 )-
(PPh 3 )] + ), 557, 627 ([Rh(η 5 -Cp*)I(PPh 3 )] + ), 897 ([M + Na] + ), 995
([Rh 2 (η 5 -Cp*) 2 I 2 (C 2 H 4 C 4 F 9 )(H 2 O)] + ); exact mass calcd for
C 34 H 34 F 9 INaPRh 897.0246, found 897.0253, Δ = 0.8 ppm.
[Rh(η 5 -Cp*){CH 2 CH 2 C(CF 3 ) 3 }I(PMe 3 )] (3c). Method A. This
was prepared in the same way as 3a starting from [Rh(η 5 -Cp*)-
(η 2 -C 2 H 4 ) 2 ] (122 mg, 0.41 mmol), PMe 3 (0.45 mmol), and IC(CF 3 ) 3
(150 mg, 0.43 mmol). The volatiles were removed under vacuum, and
the residue was extracted with n-pentane (25 mL). Evaporation of the
solvent gave an orange solid (230 mg, 80%).
Method B. IC(CF 3 ) 3 (185 mg, 0.52 mmol) was added to a solution
of [Rh(η 5 -Cp*)(η 2 -C 2 H 4 ) 2 ] (111 mg, 0.38 mmol) in n-pentane
(4 mL). After stirring for 20 h at room temperature, the solvent was
removed under vacuum, and the dark red residue was dissolved in
toluene (5 mL). Then PMe 3 (0.37 mmol) was added, and the solution
was stirred for 3 h. The volatiles were removed under vacuum, and
the residue was extracted with n-pentane (40 mL). The extract was
evaporated to dryness, and the residue was chromatographed on a
silica gel column, eluting with Et 2 O/n-hexane (1:1). The collected
fraction (R f = 0.5) was evaporated to dryness to give an orange solid
(135 mg, 52%). X-ray quality single crystals were obtained by slow
evaporation of an n-hexane solution. Mp: 135−137 °C. Anal. Calcd for
C 19 H 28 F 9 IPRh: C, 33.16; H, 4.10. Found: C, 33.22; H, 4.16. 1 H NMR
(400.9 MHz, C 6 D 6 ): δ 3.23 (m, 1 H, Rh−CH 2 −CH 2 ), 2.30 (m, 1 H,
Rh−CH 2 −CH 2 ), 1.76−1.65 (m, 2 H, Rh−CH 2 −CH 2 ), 1.45 (d, 4 J PH =
3.0 Hz, 15 H, C 5 Me 5 ), 1.11 (dd, 2 J PH = 9.9 Hz, 3 J RhH = 0.9 Hz, 9 H,
PMe 3 ). 13 C{ 1 H} NMR (75.5 MHz, CD 2 Cl 2 ): δ 122.7 (qm, 1 J CF =
287.6 Hz, CF 3 ), 98.8 (dd, 1 J RhC = 4.8 Hz, 2 J PC = 3.2 Hz, C 5 Me 5 ), 60.7
(decaplet, 2 J CF = 24.2 Hz, CCF 3 ), 36.6 (d, J PC or RhC = 3.6 Hz, Rh−
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CH 2 −CH 2 ), 17.5 (dd, 1 J PC = 32.5 Hz, 2 J RhC = 0.5 Hz, PMe 3 ), 10.1 (d,
2 J RhC = 1.1 Hz, C 5 Me 5 ), 1.6 (dd, 1 J RhC = 25.6 Hz, 2 J PC = 14.4 Hz, Rh−
CH 2 −CH 2 ). 19 F NMR (188.3 MHz, C 6 D 6 ): δ −65.0 (s). 31 P{ 1 H}
NMR (121.4 MHz, C 6 D 6 ): δ 2.6 (d, 1 J RhP = 156.4 Hz). (+)ESI-MS:
m/z 347, 441 ([Rh(η 5 -Cp*)I(PMe 3 )] + ), 706 ([M + NH 4 ] + ); exact mass
calcd for C 19 H 32 NF 9 IPRh 706.0223, found 706.0223.
[Rh(η 5 -Cp*)(CH 2 CH 2 C 6 F 5 )I(PMe 3 )] (3d). This was prepared from
[Rh(η 5 -Cp*)(η 2 -C 2 H 4 ) 2 ] (128 mg, 0.44 mmol), PMe 3 (0.44 mmol),
and IC 6 F 5 (59 μL, 0.44 mmol) in a similar way to 3a (method A).
Column chromatography (silica gel) using Et 2 O/n-hexane (3:1) as
eluent gave an orange fraction (R f = 0.87), which was evaporated to
dryness to give an orange oil (130 mg, 47%). Crystalline 3d was
obtained by slow diffusion of n-hexane into a C 6 D 6 solution. Mp:
148−151 °C. Anal. Calcd for C 21 H 28 F 5 IPRh: C, 39.64; H, 4.44. Found:
C, 39.60; H, 4.60. 1 H NMR (400.9 MHz, C 6 D 6 ): δ 2.84 (m, 1 H, Rh−
CH 2 −CH 2 ), 2.38 (m, 1 H, Rh−CH 2 −CH 2 ), 1.96 (m, 1 H, Rh−CH 2 −
CH 2 ), 1.62 (m, 1 H, Rh−CH 2 −CH 2 ), 1.58 (d, 4 J PH = 2.7 Hz, 15 H,
C 5 Me 5 ), 1.28 (dd, 2 J PH = 9.8 Hz, 3 J RhH = 0.6 Hz, 9 H, PMe 3 ). 13 C{ 1 H}
NMR (75.5 MHz, C 6 D 6 ): δ 144.7 (dm, 1 J CF = 242.2 Hz, C2 of C 6 F 5 ),
139.1 (dm, 1 J CF = 248.9 Hz, C4 of C 6 F 5 ), 137.7 (dm, 1 J CF = 250.5 Hz,
C3 of C 6 F 5 ), 119.9 (tm, 2 J CF = 19.5 Hz, C1 of C 6 F 5 ), 98.3 (dd, 1 J RhC =
4.5 Hz, 2 J PC = 3.5 Hz, C 5 Me 5 ), 30.1 (d, J PC or RhC = 5.7 Hz, RhCH 2 CH 2 ),
17.4 (d, 1 J PC = 32.1 Hz, PMe 3 ), 13.6 (dd, 1 J RhC = 25.3 Hz, 2 J PC = 14.6
Hz, Rh−CH 2 −CH 2 ), 10.0 (s, C 5 Me 5 ). 19 F NMR (188.3 MHz, C 6 D 6 ): δ
−146.3 (m, 2 F, F2), −160.5 (m, 1 F, F4), −163.3 (m, 2 F, F3).
31 P{ 1 H} NMR (81.0 MHz, C 6 D 6 ): δ 3.9 (d, 1 J RhP = 159.5 Hz). (+)ESI-
MS (MeCOMe): m/z 194 ([C 6 F 5 −C 2 H 3 ] + ), 237 ([Rh(C 5 Me 4 CH 2 )] + ),
365 ([Rh(η 5 -Cp*)I] + ), 441 ([Rh(η 5 -Cp*)I(PMe 3 )] + ), 636 (M + ).
[Rh(η 5 -Cp*)(CH 2 CH 2 CF 2 C 6 F 5 )I(PPh 3 )] (3e′). This was prepared
from [Rh(η 5 -Cp*)(η 2 -C 2 H 4 ) 2 ] (100 mg, 0.34 mmol), PPh 3 (90 mg,
0.34 mmol), and ICF 2 C 6 F 5 (54 μL, 0.34 mmol) in a similar way to 3a′
(method A). After 15 h the resulting suspension was filtered. The
precipitate was identified as [Rh(η 5 -Cp*)I 2 (PPh 3 )] by NMR spectroscopy
(see below). The filtrate was purified by column
chromatography (silica gel) using Et 2 O/n-hexane (1:1) as eluent.
The orange fraction (R f = 0.7) was evaporated to dryness to give an
orange solid (37 mg, 12%). Yellow-orange crystals were obtained from
Et 2 O/n-pentane at −32 °C. Mp: 141−143 °C. Anal. Calcd for
C 37 H 34 F 7 IPRh: C, 50.94; H, 3.93. Found: C, 50.53; H, 3.57. 1 H NMR
(300.1 MHz, CDCl 3 ): δ 7.65−7.10 (br m, 15 H, Ph), 2.92 (m, 1 H,
Rh−CH 2 −CH 2 ), 2.07 (m, 1 H, Rh−CH 2 −CH 2 ), 1.59 (m, 1 H, Rh−
CH 2 −CH 2 ), 1.28 (m, 1 H, Rh−CH 2 −CH 2 ), 1.51 (d, 4 J PH = 2.8 Hz, 15
H, C 5 Me 5 ). 13 C{ 1 H} NMR (75.5 MHz, CDCl 3 ): δ 137.6−131.8 (br m,
Ph), 129.8 (br s, Ph), 127.7 (br s, Ph), 99.6 (dd, 1 J RhC = 4.6 Hz, 2 J PC =
3.1 Hz, C 5 Me 5 ), 47.4 (t, 2 J FC = 21.6 Hz, Rh−CH 2 −CH 2 ), 9.3 (s,
C 5 Me 5 ), 3.1 (ddd, 1 J RhC = 24.8 Hz, 2 J PC = 13.4 Hz, 3 J FC = 2.6 Hz, Rh−
CH 2 −CH 2 ). The signals of the CF 2 C 6 F 5 carbons could not be assigned
because of their low intensity and overlap with phenylic signals. 19 F
NMR (188.3 MHz, CDCl 3 ): δ −84.6 (dm, 2 J FF = 255.3 Hz, 1 F, CF 2 ),
−95.4 (dm, 2 J FF = 257.6 Hz, 1 F, CF 2 ), −140.6 (m, 2 F, F2 of C 6 F 5 ),
−152.9 (t, 1 F, 2 J FF = 21.1 Hz, F4 of C 6 F 5 ), −161.9 (m, 2 F, F3 of
C 6 F 5 ). 31 P{ 1 H} NMR (81.0 MHz, CDCl 3 ): δ 41.6 (d, 1 J RhP = 161.8
Hz). (+)ESI-MS: m/z 496, 499 ([Rh(C 5 Me 4 CH 2 )(PPh 3 )] + ), 537, 565,
627 ([Rh(η 5 -Cp*)I(PMe 3 )] + ), 721, 745 ([Rh(η 5 -Cp*)-
(C 2 H 4 CF 2 C 6 F 5 )(PMe 3 )] + ), 911 ([M + K] + ); exact mass calcd for
C 37 H 34 F 7 IKPRh 911.0023, found 911.0000, Δ = 2.5 ppm. [Rh(η 5 -
Cp*)I 2 (PPh 3 )]: 1 H NMR (300.1 MHz, CDCl 3 ): δ 7.82−7.20 (several
br m, 15 H, Ph), 1.76 (d, 3 J RhH = 3.3 Hz, 15 H, C 5 Me 5 ). 31 P{ 1 H} NMR
(121.5 MHz, CDCl 3 ): δ 27.8 (d, 1 J RhP = 148.7 Hz). These data are in
agreement with those of a sample prepared by a reported method. 69,70
[Rh(η 5 -Cp*)(CF 2 C 6 F 5 )I(PMe 3 )] (4e). This was prepared from
[Rh(η 5 -Cp*)(η 2 -C 2 H 4 ) 2 ] (137 mg, 0.47 mmol), PMe 3 (0.56 mmol),
and ICF 2 C 6 F 5 (76 μL, 0.48 mmol) in a similar way to 3a (method A).
Column chromatography (silica gel) using Et 2 O/n-hexane (3:1) as eluent
gave an orange fraction (R f = 0.6), which was evaporated to dryness to
give an orange solid (165 mg, 47%). The 1 H, 19 F, and 31 P{ 1 H} NMR
data of this compound agreed with those previously reported. 22
Reaction of [Rh(η 5 -Cp*)(η 2 -C 2 H 4 )(PMe 3 )] with I n C 3 F 7 . PMe 3
(0.054 mmol) was added to a solution of [Rh(η 5 -Cp*)(η 2 -C 2 H 4 ) 2 ]
(16 mg, 0.054 mmol) in C 6 D 6 (0.5 mL) in an NMR tube. The tube
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Organometallics
was closed and heated at 120 °C for 20 h. Then, it was cooled to room
temperature, and I n C 3 F 7 (8 μL, 0.054 mmol) was added. After 24 h,
1 H, 19 F, and 31 P{ 1 H} NMR spectra of the resulting dark red-brown
solution were measured. [Rh(η 5 -Cp*)( n C 3 F 7 )I(PMe 3 )] (4f) 21 and
[Rh(η 5 -Cp*)I 2 (PMe 3 )] 69,70 were the main reaction products,
accounting respectively for 40% and 27% of the mixture (the ratio is
based on the integration of the 31 P{ 1 H} NMR spectra of the mixture).
Their NMR data were in agreement with those previously reported. 4f:
1 H NMR (300.1 MHz, C 6 D 6 ) δ 1.50 (d, 3 J RhH = 3.3 Hz, 15 H, C 5 Me 5 ),
1.24 (d, 2 J PH = 10.6 Hz, 9 H, PMe 3 ). 19 F NMR (282.4 MHz, C 6 D 6 ):
δ −66.1 (AB d, 2 J FF = 272.4 Hz, 1 F, RhCF 2 ), −68.7 (AB d, 2 J FF =269.3
Hz, 1 F, RhCF 2 ), −78.5 (t, 3 J FF =11.3Hz,3F,CF 3 ), −113.3 (AB d, 2 J FF =
279.7 Hz, 1 F, CF 2 CF 3 ), −114.9 (AB d, 2 J FF = 279.1 Hz, 1 F, CF 2 CF 3 ).
31 P{ 1 H} NMR (121.5 MHz, C 6 D 6 ): δ 2.7 (dm, 1 J RhP =150.7Hz).
[Rh(η 5 -Cp*)I 2 (PMe 3 )]: 1 H NMR (300.1 MHz, C 6 D 6 ): δ 1.58 (d,
3 J RhH =3.4Hz,15H,C 5 Me 5 ), 1.48 (d, 2 J PH =10.1Hz,9H,PMe 3 ).
31 P{ 1 H} NMR (121.5 MHz, C 6 D 6 ): δ −2.0 (d, 1 J RhP =138.2Hz).
[Rh(η 5 -Cp*)( n C 4 F 9 )I(PMe 3 )] (4g). This was prepared from
[Rh(η 5 -Cp*)(η 2 -C 2 H 4 ) 2 ] (150 mg, 0.51 mmol), PMe 3 (0.61 mmol),
and I n C 4 F 9 (90 μL, 0.51 mmol) in a similar way to 3a (method A).
Column chromatography (silica gel) using Et 2 O as eluent gave an
orange fraction (R f = 0.95), which was evaporated to dryness to give an
orange oil (40 mg, 12%). X-ray quality single crystals were obtained by
slow evaporation of a toluene solution. Mp: 153−156 °C. Anal. Calcd
for C 17 H 24 F 9 IPRh: C, 30.93; H, 3.66. Found: C, 31.01; H, 3.36. 1 H
NMR (400.9 MHz, C 6 D 6 ): δ 1.49 (d, 4 J PH = 2.8 Hz, 15 H, C 5 Me 5 ),
1.23 (d, 2 J PH = 10.5 Hz, 9 H, PMe 3 ). 13 C{ 1 H} NMR (75.5 MHz,
C 6 D 6 ): δ 101.5 (dd, 1 J RhC = 4.5 Hz, 2 J PC = 2.9 Hz, C 5 Me 5 ), 19.0 (d,
1 J PC = 33.3 Hz, PMe 3 ), 10.4 (s, C 5 Me 5 ). The signals corresponding to
the carbons of the n C 4 F 9 group were not observed. 19 F NMR (188.3
MHz, C 6 D 6 ): δ −66.2 (AB d, 2 J FF = 272.1 Hz, 1 F, RhCF 2 ), −68.3 (AB
d, 2 J FF = 273.0 Hz, 1 F, RhCF 2 ), −80.8 (s, 3 F, CF 3 ), −110.3 (AB d,
2 J FF = 285.4 Hz, 1 F, C β F 2 ), −111.7 (AB d, 2 J FF = 285.4 Hz, 1 F, C β F 2 ),
−124.6 (m, 2 F, C γ F 2 ). 31 P{ 1 H} NMR (81.0 MHz, C 6 D 6 ): δ 2.7 (dm,
1 J RhP = 150.5 Hz).
[Rh(η 5 -Cp*)(CFCF 2 )I(PMe 3 )] (4h). This was prepared from
[Rh(η 5 -Cp*)(η 2 -C 2 H 4 ) 2 ] (157 mg, 0.53 mmol), PMe 3 (0.64 mmol),
and ICFCF 2 (53 μL, 0.56 mmol) in a similar way to 3a (method A).
Column chromatography (silica gel) using Et 2 O/n-hexane (3:1) as
eluent gave an orange fraction (R f = 0.6), which was evaporated to
dryness to give an orange solid (40 mg, 14%). Mp: 132−135 °C. Anal.
Calcd for C 15 H 24 F 3 IPRh: C, 34.51; H, 4.63. Found: C, 34.21; H, 4.68.
1 H NMR (300.1 MHz, C 6 D 6 ): δ 1.53 (d, 4 J PH = 2.9 Hz, 15 H, C 5 Me 5 ),
1.30 (d, 2 J PH = 10.8 Hz, 9 H, PMe 3 ). 13 C{ 1 H} NMR (75.5 MHz,
C 6 D 6 ): δ 160.2 (ddd, 1 J CF = 311.7 and 259.8 Hz, 2 J CF = 47.4 Hz, CF
CF 2 ), 100.1 (dd, 1 J RhC = 4.5 Hz, 2 J PC = 3.0 Hz, C 5 Me 5 ), 18.3 (d, 1 J PC =
34.3 Hz, PMe 3 ), 10.0 (s, C 5 Me 5 ). The signal corresponding to the
CFCF 2 carbon was not observed. 19 F NMR (282.4 MHz, C 6 D 6 ):
δ −90.4 (dd, 2 J FF = 93.9 Hz, 3 J FF cis = 38.8 Hz, RhCCF trans to Rh),
−121.9 (dd, 2 J FF = 93.7 Hz, 3 J FF trans = 109.4 Hz, RhCCF cis to Rh),
−140.4 (ddt, 3 J FF trans = 110.3 Hz, 3 J FF cis = 3 J PF = 36.9 Hz, 2 J RhF = 15.0
Hz, RhCFC). 31 P{ 1 H} NMR (81.0 MHz, C 6 D 6 ): δ 6.0 (dd, 1 J RhP =
140.8 Hz, 3 J PF = 39.9 Hz).
Reaction of [Rh(η 5 -Cp*)(η 2 -C 2 H 4 )(PMe 3 )] with ICF(CF 3 )-
CF 2 CF 3 . PMe 3 (0.07 mmol) was added to a solution of [Rh(η 5 -
Cp*)(η 2 -C 2 H 4 ) 2 ] (21 mg, 0.071 mmol) in C 6 D 6 (0.5 mL) in an NMR
tube. The tube was closed and heated at 120 °C until the conversion
of the starting complex into [Rh(η 5 -Cp*)(η 2 -C 2 H 4 )(PMe 3 )] was
complete according to the 1 H and 31 P{ 1 H} NMR spectra (24 h).
Then, ICF(CF 3 )CF 2 CF 3 was added (12 μL, 0.073 mmol). A fast color
change from yellow to dark red was observed. After 24 h at room
temperature, a crystalline orange-red solid precipitated. After
measuring NMR spectra, the solution was removed and the solid
was washed with toluene (3 × 0.5 mL) and Et 2 O(3× 1 mL) and
dried under vacuum. In the 19 F NMR spectrum of the solution, the
main signals corresponded to trans- and cis-octafluoro-2-butene: 71 19 F
NMR (188.3 MHz, C 6 D 6 ): δ (trans isomer) −69.1 (m, 6 F, CF 3 ),
−159.8 (m, 2 F, CF); (cis isomer) −66.7 (m, 6 F, CF 3 ), −141.6 (m, 2
F, CF). Data of the solid: 1 H NMR (300.1 MHz, CD 2 Cl 2 ,21°C): δ
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13.8 (very br s, 1 H, F n+1 H − n ), 1.94 (t, 4 J PH = 3.2 Hz, 15 H, C 5 Me 5 ),
1.76 (m, 9 H, PMe 3 ); (−90 °C) δ 16.2 (br t, 1 J FH = 121 Hz, HF − 2 ),
13.7 (br d, 1 J FH = 352 Hz, H 2 F − 3 ), 1.83 (br s, C 5 Me 5 ), 1.64 (br s, 9 H,
PMe 3 ). 19 F NMR (282.4 MHz, CD 2 Cl 2 ,21°C): δ −128.2 (very br s,
SiF 2− 6 ), −165.4 (very br s, F n+1 H − n ); (−90 °C) δ −128.5 (br s,
SiF 2− 6 ), −146.6 (br t, 1 J FH = 131.5 Hz, [FHFHF] − ), −149.5 (br d, 1 J FH =
123.6 Hz, [FHF] − ), −174.3 (br dd, 1 J FH = 350.0 Hz, 2 J FF = 130.9 Hz,
[FHFHF] − ). 31 P{ 1 H} NMR (81.0 MHz, CD 2 Cl 2 ): δ 1.2 (d, 1 J RhP =
131.9 Hz). (+)ESI-MS: m/z 517 ([Rh(η 5 -Cp*)I(PMe 3 ) 2 ] + ); exact mass
calcd for C 16 H 33 IP 2 Rh 517.0152, found 517.0171, Δ =3.7ppm.
[Rh(η 5 -Cp)( n C 4 F 9 )I(PMe 3 )] (5). A solution of [Rh(η 5 -Cp)(η 2 -C 2 H 4 )-
(PMe 3 )] (290 mg, 1.07 mmol) in n-pentane (10 mL) was treated with
I n C 4 F 9 (0.19 mL, 1.08 mmol). The mixture was stirred for 10 min.
An orange solid precipitated, which was filtered, washed with n-pentane
(2 × 10 mL), and dried under vacuum (302 mg, 48%). Mp: 196−
198 °C. Anal. Calcd for C 12 H 14 F 9 IPRh: C, 24.43; H, 2.39. Found: C,
24.31; H, 2.44. 1 H NMR (200.1 MHz, CDCl 3 ): δ 5.52 (d, 2 J RhH =1.5
Hz, 5 H, C 5 H 5 ), 1.81 (d, 2 J PH =11.4Hz,9H,PMe 3 ). 13 C{ 1 H} NMR
(100.8 MHz, C 6 D 6 ): δ 135.3 (m, CF 2 ), 117.9 (qt, 1 J FC = 288.1 Hz,
2 J FC = 34.1 Hz, CF 3 ), 114.9−106.1 (two overlapped multiplets, 2 CF 2 ),
90.4 (s, C 5 H 5 ), 21.0 (d, 1 J PC = 35.6 Hz, PMe 3 ). 19 F NMR (188.3 MHz,
CDCl 3 ): δ −54.8 (AB d, 2 J FF = 254.2 Hz, 1 F, C α F A ), −66.5 (AB d,
2 J FF = 257.0 Hz, 1 F, C α F B ), −81.7 (br s, 3 F, CF 3 ), −110.0 (AB d, 2 J FF =
281.9Hz,1F,C β F A ), −111.8 (AB d, 2 J FF = 279.6 Hz, 1 F, C β F B ), −125.7
(m, 2 F, C γ F 2 ). 31 P{ 1 H} NMR (81.0 MHz, C 6 D 6 ): δ 9.8 (dddd, 1 J RhP =
146.0 Hz, J PF = 21.9, 9.5, and 6.4 Hz).
[Rh(η 5 -Cp*){CH 2 CH 2 CF(CF 3 ) 2 }(CNXy)(PPh 3 )](OTf) (6). AgOTf
(36 mg, 0.14 mmol) was added to a solution of 3a′ (116 mg,
0.14 mmol) in THF (9 mL). The mixture was stirred for 2 h at room
temperature and evaporated to dryness. The residue was stirred with
CH 2 Cl 2 (9 mL), and the suspension was filtered. XyNC (19 mg,
0.14 mmol) was added to the resulting orange solution. After stirring
for 5 h at room temperature, the resulting light orange solution was
evaporated to dryness. The residue was washed with Et 2 O(3× 5 mL)
and dried under vacuum to give 5 as a yellowish-brown solid (106 mg,
87%). Anal. Calcd for C 43 H 43 F 10 NO 3 PRhS: C, 52.82; H, 4.43; N, 1.43;
S, 3.28. Found: C, 52.53; H, 4.50; N, 1.51; S, 3.24. IR (Nujol, cm −1 ):
ν(CN) 2133. 1 H NMR (400.9 MHz, CD 2 Cl 2 ): δ 7.59 (m, 3 H, H4
of Ph), 7.51 (m, 6 H, H3 of Ph), 7.31 (m, 7 H, H2 of Ph and H4 of
Xy), 7.17 (d, 3 J HH = 7.6 Hz, 2 H, H3 of Xy), 2.37−2.22 (m, 2 H,
CH 2 CF), 2.18 (s, 6 H, Me of Xy), 1.80−1.57 (m, 2 H, RhCH 2 ), 1.67
(d, 4 J PH = 2.9 Hz, 15 H, C 5 Me 5 ). 13 C{ 1 H} NMR (100.8 MHz,
CDCl 3 ): δ 151.7 (dd, 1 J RhC = 72.1 Hz, 2 J PC = 25.2 Hz, CN), 135.2
(s, C2 of Xy), 133.3 (d, 2 J PC = 9.7 Hz, C2 or C3 of Ph), 132.1 (s, C4 of
Ph), 130.4 (s, C4 of Xy), 129.3 (br d, 2 J PC = 48.2 Hz, C1 of Ph), 129.3
(d, 2 J PC = 10.5 Hz, C3 or C2 of Ph), 128.8 (s, C3 of Xy), 126.5 (s, C−
N), 120.81 (qd, 1 J FC = 286.6 Hz, 2 J FC = 28.2 Hz, CF 3 ), 120.74 (qd,
1 J FC = 286.7 Hz, 2 J FC = 28.1 Hz, CF 3 ), 104.9 (d, 1 J RhC = 2.1 Hz, 2 J PC =
3.9 Hz, C 5 Me 5 ), 91.0 (d of septuplets, 1 J FC = 201.7 Hz, 2 J FC = 31.0 Hz,
CF), 35.3 (d, 2 J FC = 21.5 Hz, CH 2 CF), 18.8 (s, MeAr), 9.3 (s, C 5 Me 5 ),
4.8 (dd, 1 J RhC = 23.4 Hz, 2 J PC = 9.4 Hz, RhCH 2 ). 19 F NMR (188.3
MHz, CDCl 3 ): δ −75.4 (dq, 3 J FF = 4 J FF = 8.6 Hz, CF 3 CF), −76.9 (dq,
3 J FF = 4 J FF = 8.6 Hz, CF 3 CF), −79.0 (s, OTf), −184.9 (m, CF).
31 P{ 1 H} NMR (81.0 MHz, CDCl 3 ): δ 43.5 (d, 1 J RhP = 131.0 Hz).
(+)ESI-MS: m/z 828 (M + ); exact mass calcd for C 42 H 43 F 7 NPRh
828.2071, found 828.2087, Δ = 1.9 ppm.
[Rh(η 5 -Cp*){C(O)CH 2 CH 2 CF(CF 3 ) 2 }(CO)(PPh 3 )]OTf (7). AgOTf
(32 mg, 0.12 mmol) was added to a solution of 3a′ (100 mg,
0.12 mmol) in THF (10 mL), and the mixture was stirred at room
temperature for 2 h and evaporated to dryness. The residue was
extracted with CH 2 Cl 2 (8 mL), and the extract was filtered. CO was
bubbled through the extract for 3 min. Then, the reaction tube was
closed and the solution was stirred for 48 h at room temperature. A
small amount of black precipitate was removed by filtration, and the
filtrate was evaporated to dryness to give a dark yellow solid, which
was washed with n-pentane (3 × 3 mL) to give crude 7 (73 mg, 69%).
Yellow, analytically pure crystals were obtained by liquid diffusion of
n-pentane into a CH 2 Cl 2 solution. Mp: 144−146 °C. Anal. Calcd for
C 36 H 34 F 10 O 5 PRhS: C, 47.91; H, 3.80; S, 3.55. Found: C, 48.23; H,
3.79; S, 3.35. IR (Nujol, cm −1 ): ν(CO) 2043 (CO), 1682 (CO).
dx.doi.org/10.1021/om2009588 | Organometallics 2012, 31, 1287−1299

Organometallics
Article
Table 2. Crystallographic Data
1a·C 6 D 6 1b 3c 4g 7 8
formula C 36 H 38 D 6 F 14 I 2 Rh 2 C 32 H 38 F 18 I 2 Rh 2 C 19 H 28 F 9 IPRh C 17 H 24 F 9 IPRh C 36 H 34 F 10 O 5 PRhS C 18 H 29 BF 4 INPRh
cryst size (mm 3 ) 0.20 × 0.15 × 0.04 0.17 × 0.11 × 0.10 0.18 × 0.12 × 0.08 0.26 × 0.18 × 0.04 0.21 × 0.19 × 0.08 0.4 × 0.3 × 0.2
cryst syst triclinic monoclinic monoclinic monoclinic monoclinic monoclinic
space group P1̅ P2 1 /n P2 1 /c P2 1 /c P2 1 /c P2 1 /c
a (Å) 12.4747(4) 14.6027(14) 17.4942(15) 9.4279(4) 16.6976(11) 8.1288(3)
b (Å) 13.3277(5) 8.1396(8) 10.7840(9) 13.1022(5) 13.5697(9) 21.5156(6)
c (Å) 15.0019(5) 16.9438(16) 13.5254(12) 18.0704(7) 16.8812(11) 12.9148(4)
α (deg) 70.372(2) 90 90 90 90 90
β (deg) 66.215(2) 103.877(2) 107.105(2) 99.886(2) 103.331(2) 95.866(3)
γ (deg) 66.821(2) 90 90 90 90 90
V (Å 3 ) 2051.06(12) 1955.2(3) 2438.8(4) 2199.02(15) 3721.9(4) 2246.92(13)
Z 2 2 4 4 4 4
ρ calcd (g cm −3 ) 1.956 2.080 1.874 1.994 1.611 1.794
F 000 1164 1176 1344 1280 1824 1192
μ (mm −1 ) 2.399 2.533 2.104 2.329 0.650 2.24
transmns 0.9101−0.6175 0.7858−0.5468 0.8497−0.6499 0.9126−0.6541 0.9499−0.8049 1.000−0.842
θ range (deg) 1.52−28.24 2.11−25.68 2.25−28.61 1.93−28.09 1.95−28.74 2.52−31.0
reflns collected 23 839 19 522 16 032 24 816 58 112 101 180
R int 0.0256 0.0492 0.0254 0.0223 0.0280 0.037
data/restraints/params 9196/12/493 3703/0/249 5737/0/288 5074/0/270 9096/13/485 7156/0/252
GOF 1.057 1.092 1.192 1.038 1.064 1.11
R1 a 0.0355 0.0433 0.0371 0.0190 0.0470 0.0296
wR2 b 0.0781 0.1081 0.0739 0.0462 0.1149 0.0699
largest diff peak, hole (e Å −3 ) 1.049, −0.862 2.951, −0.745 0.921, −0.464 0.574, −0.450 1.280, −1.318 2.48, −1.13
a R1 = ∑||F o | − |F c ||/∑|F o | for reflections with I >2σ(I). b wR2 = [∑[w(F 2 o − F 2 c ) 2 ]/∑[w(F 2 o ) 2 ] 0.5 for all reflections; w −1 = σ 2 (F 2 )+(aP) 2 + bP,
where P =(2F 2 c + F 2 o )/3 and a and b are constants set by the program.
1 H NMR (200.1 MHz, CDCl 3 ): δ 7.64−7.52 (m, 9 H, H3 and H4 of
Ph), 7.43−7.34 (m, 6 H, H2 of Ph), 2.93−2.76 (m, 1 H, CH 2 ), 2.46−
2.29 (m, 1 H, CH 2 ), 2.18−1.99 (m, 1 H, CH 2 ), 1.78−1.64 (m, 1 H,
CH 2 ), 1.72 (d, 4 J PH = 3.2 Hz, 15 H, C 5 Me 5 ). 13 C{ 1 H} NMR (75.5
MHz, CDCl 3 ): δ 229.5 (dd, 1 J RhC = 27.1 Hz, 2 J PC = 9.5 Hz, CO),
190.0 (dd, 1 J RhC = 76.2, 2 J PC = 20.1, CO), 133.4 (br d, J PC = 9.9 Hz,
C2 of Ph), 132.7 (d, J PC = 2.2 Hz, C4 of Ph), 129.7 (d, J PC = 11.1 Hz,
C3 of Ph), 120.7 (qd, 1 J FC = 286.8 Hz, 2 J FC = 27.9 Hz, CF 3 ), 109.6
(dd, 1 J RhC = 3.5 Hz, 2 J PC = 1.2 Hz, C 5 Me 5 ), 90.8 (d of septuplets,
1 J FC = 204.0 Hz, 2 J FC = 32.2 Hz, CF), 54.7 (s, CH 2 ), 24.3 (d, 2 J FC = 20.7
Hz, CH 2 CF), 9.6 (s, C 5 Me 5 ). The signal of the C1 of Ph could not be
located. 19 F NMR (282.4 MHz, CDCl 3 ): δ −76.9 (m, CF 3 CF), −78.6
(s, OTf), −185.9 (m, CF). 31 P{ 1 H} NMR (81.1 MHz, CDCl 3 ): δ 31.6
(d, 1 J RhP = 136.9 Hz). (+)ESI-MS: m/z 725 ([Rh(η 5 -Cp*)(PPh 3 )-
(COCH 2 CH 2 C 3 F 7 )] + ), 753 ([Rh(η 5 -Cp*)(PPh 3 )(COCH 2 -
CH 2 C 3 F 7 )] + ); exact mass calcd for M + (C 35 H 34 O 2 PF 7 Rh) 753.1234;
found 753.1243 (Δ = 1.2 ppm).
[Rh(η 5 -Cp*)I(py)(PMe 3 )](BF 4 )(8). Method A. A solution of
[Rh(η 5 -Cp*)(η 2 -C 2 H 4 ) 2 ] (154 mg, 0.52 mmol) and PMe 3 (0.52 mmol)
in toluene (4 mL) was stirred at 120 °C for 24 h in a Carius tube. The
resulting solution of [Rh(η 5 -Cp*)(η 2 -C 2 H 4 )(PMe 3 )] was cooled to
room temperature, and [I(py) 2 ](BF 4 ) (195 mg, 0.52 mmol) was
added. The mixture was vigorously stirred for 24 h. An orange solid
precipitated, which was decanted, washed with Et 2 O(3× 5 mL), and
dried under vacuum (202 mg, 64%).
Method B. AgBF 4 (72 mg, 0.37 mmol) was added to a solution of
[Rh(η 5 -Cp*)I 2 (PMe 3 )] (208 mg, 0.37 mmol) in THF (10 mL) After
stirring for 30 min in the dark, pyridine (30 μL, 0.37 mmol) was added.
Thesuspensionwasstirredfor30minmoreandthenevaporatedto
dryness. The residue was extracted with CH 2 Cl 2 (10 mL). The suspension
was filtered, and the filtrate was evaporated to dryness under
vacuum. On addition of Et 2 O (15 mL), an orange solid precipitated,
which was filtered, washed with n-pentane (5 mL), and dried under
vacuum (133 mg, 60%). X-ray quality single crystals were obtained
by liquid diffusion (CH 2 Cl 2 /n-hexane). Mp: 218−220 °C. Anal. Calcd
for C 18 H 29 BF 4 INPRh: C, 35.62; H, 4.82; N, 2.31. Found: C, 35.78;
1297
H, 4.98; N, 2.28. 1 H NMR (400.9 MHz, CD 2 Cl 2 ): δ 8.86 (br m, 2 H,
H2 of py), 7.97 (m, 1 H, H4 of py), 7.55 (m, 2 H, H3 of py), 1.75 (d,
4 J PH = 3.4 Hz, 15 H, C 5 Me 5 ), 1.66 (dd, 2 J PH = 10.7 Hz, 3 J RhH = 0.5 Hz,
9 H, PMe 3 ). 13 C{ 1 H} NMR (100.8 MHz, CD 2 Cl 2 ): δ 156.9 (br s, C2
of py), 139.9 (s, C4 of py), 127.9 (s, C3 of py), 100.9 (dd, 1 J RhC = 6.2
Hz, 2 J PC = 2.6 Hz, C 5 Me 5 ), 16.9 (d, 1 J PC = 33.9 Hz, PMe 3 ), 10.2 (s,
C 5 Me 5 ). 19 F NMR (188.3 MHz, CD 2 Cl 2 ): δ −152.7 (s, 10 BF 4 ), −152.6
(s, 11 BF 4 ). 31 P{ 1 H} NMR (100.8 MHz, CD 2 Cl 2 ): δ 2.0 (d, 1 J RhP =
137.7 Hz).
Anion Trapping Experiments. Typical Procedure. Complex
[Rh(η 5 -Cp*)(η 2 -C 2 H 4 )(PMe 3 )] was generated in situ by heating
[Rh(η 5 -Cp*)(η 2 -C 2 H 4 ) 2 ] (15 mg, 0.051 mmol) and PMe 3 (55 μL ofa
1 M toluene solution, 0.055 mmol) in C 6 D 6 or D 8 -toluene (0.5 mL) at
120 °C for 24 h in an NMR tube. Then, CH 3 OD and IR F were
consecutively added. After 1 h, the NMR spectra of the dark red
solution were measured. The NMR data of the detected species (DR F
or HR F ;R F = CF(CF 3 ) 2 , 65,72 C(CF 3 ) 3 , 72,73 n C 4 F 9 , 71,72 and C 6 F 74 5 ) are
given in the Supporting Information.
X-ray Crystallography. Complexes 1a, 1b, 3c, 4g, and 7 were
measured on a Bruker Smart APEX, and 8 was measured on an Oxford
Diffraction Xcalibur S diffractometer. Data were collected using monochromated
Mo Kα radiation in ω-scan mode at 100 K. Absorption
corrections were applied on the basis of multiscans (Program SADABS
for complexes 1a, 1b, 3c, 4g, and 7 and CrysAlis RED for 8). All structures
were refined anisotropically on F 2 . The methyl groups were
refined using rigid groups (AFIX 137), and the other hydrogens were
refined using a riding model. Special features and exceptions: For
complex 1a, two CF 3 groups are disordered over two positions; for
complex
■
7, all the CF 3 groups are disordered over two positions.
ASSOCIATED CONTENT
*S Supporting Information
Variable-temperature 1 Hand 19 F NMR spectra of [Rh(η 5 -Cp*)-
I(PMe 3 ) 2 ]F n+1 H n . NMR data of the DR F or HR F species detected
in the anion trapping experiments. Crystallographic information in
dx.doi.org/10.1021/om2009588 | Organometallics 2012, 31, 1287−1299

Organometallics
CIF format. This material is available free of charge via the
Internet
■
at http://pubs.acs.org.
AUTHOR INFORMATION
Corresponding Author
*E-mail: jgr@um.es, http://www.um.es/gqo/.
■ ACKNOWLEDGMENTS
We thank the Spanish Ministerio de Ciencia e Innovacioń
(grant CTQ2007-60808/BQU, with FEDER support) and
Fundacioń Seńeca (grants 02992/PI/05 and 04539/GERM/06)
for financial support.
■ DEDICATION
† DedicatedtoProf.JuanFornieś on the occasion of his retirement.
■ REFERENCES
(1) Engle, K. M.; Mei, T.-S.; Wang, X.; Yu, J.-Q. Angew. Chem., Int.
Ed. 2011, 50, 1478.
(2) Tomashenko, O. A.; Grushin, V. V. Chem. Rev. 2011, 111, 4475.
(3) Furuya, T.; Kamlet, A. S.; Ritter, T. Nature 2011, 473, 470.
(4) Morrison, J. A. Adv. Organomet. Chem. 1993, 35, 211.
(5) Hughes, R. P. Adv. Organomet. Chem. 1990, 31, 183.
(6) Grushin, V. V.; Marshall, W. J. J. Am. Chem. Soc. 2006, 128, 12644.
(7) Dubinina, G. G.; Brennessel, W. W.; Miller, J. L.; Vicic, D. A.
Organometallics 2008, 27, 3933.
(8) Ball, N. D.; Kampf, J. W.; Sanford, M. S. J. Am. Chem. Soc. 2010,
132, 2878.
(9) Ye, Y.; Ball, N. D.; Kampf, J. W.; Sanford, M. S. J. Am. Chem. Soc.
2010, 132, 14682.
(10) Ball, N. D.; Gary, J. B.; Ye, Y.; Sanford, M. S. J. Am. Chem. Soc.
2011, 133, 7577.
(11) Dolbier, W. R. Chem. Rev. 1996, 96, 1557.
(12) Chen, Q.-Y.; Yang, Z.-Y. J. Fluorine Chem. 1988, 39, 217.
(13) Xiao, F.; Wu, F.; Yang, X.; Shen, Y.; Shi, X. J. Fluorine Chem.
2005, 126, 319.
(14) Von Werner, K. J. Fluorine Chem. 1985, 28, 229.
(15) Ishihara, T.; Kuroboshi, M.; Okada, Y. Chem. Lett. 1986, 1895.
(16) Urata, H.; Yugari, H.; Fuchikami, T. Chem. Lett. 1987, 833.
(17) Hu, C.-M.; Qiu, Y.-L. J. Fluorine Chem. 1991, 55, 113.
(18) Wang, X.; Truesdale, L.; Yu, J.-Q. J. Am. Chem. Soc. 2010, 132,
3648.
(19) Hughes, R. P.; Lindner, D. C.; Smith, J. M.; Zhang, D.;
Incarvito, C. D.; Lam, K.-C.; Liable-Sands, L. M.; Sommer, R. D.;
Rheingold, A. L. J. Chem. Soc., Dalton Trans. 2001, 2270.
(20) Bourgeois, C. J.; Huang, H.; Larichev, R. B.; Zakharov, L. N.;
Rheingold, A. L.; Hughes, R. P. Organometallics 2007, 26, 264.
(21) Hughes, R. P.; Lindner, D. C. J. Am. Chem. Soc. 1997, 119, 11544.
(22) Hughes, R. P.; Lindner, D. C.; Rheingold, A. L.; Yap, G. P. A.
Organometallics 1996, 15, 5678.
(23) McCleverty, J. A.; Wilkinson, G. J. Chem. Soc. 1964, 4200.
(24) Hughes, R. P.; Le Husebo, T. Organometallics 1997, 16, 5.
(25) King, R. B.; Efraty, A. J. Organomet. Chem. 1972, 36, 371.
(26) Gardner, S. A.; Rausch, M. D. Inorg. Chem. 1974, 13, 997.
(27) Churchill, M. R. Inorg. Chem. 1965, 4, 1734.
(28) Hughes, R. P.; Laritchev, R. B.; Williamson, A.; Incarvito, C. D.;
Zakharov, L. N.; Rheingold, A. L. Organometallics 2002, 21, 4873.
(29) Hughes, R. P.; Le Husebo, T.; Maddock, S. M.; Liable-Sands,
L. M.; Rheingold, A. L. Organometallics 2002, 21, 243.
(30) Hughes, R. P.; Le Husebo, T.; Holliday, B. J.; Rheingold, A. L.;
Liable-Sands, L. M. J. Organomet. Chem. 1997, 548, 109.
(31) Hughes, R. P.; Smith, J. M.; Liable-Sands, L. M.; Concolino,
T. E.; Lam, K.-C.; Incarvito, C. D.; Rheingold, A. L. J. Chem. Soc.,
Dalton Trans. 2000, 873.
(32) Bourgeois, C. J.; Hughes, R. P.; Husebo, T. L.; Smith, J. M.;
Guzei, I. A.; Liable-Sands, L. M.; Zakharov, L. N.; Rheingold, A. L.
Organometallics 2005, 24, 6431.
Article
(33) Yuan, J.; Hughes, R. P.; Rheingold, A. L. Organometallics 2011,
30, 1744.
(34) Moseley, K.; Kang, J. W.; Maitlis, P. M. J. Chem. Soc. A 1970,
2875.
(35) Werner, H.; Feser, R. J. Organomet. Chem. 1982, 232, 351.
(36) King, R. B. Inorg. Chem. 1963, 2, 528.
(37) Klingert, B.; Werner, H. Chem. Ber. 1983, 116, 1450.
(38) Mukhedkar, A. J.; Mukhedkar, V. A.; Green, M.; Stone, F. G. A.
J. Chem. Soc. A 1970, 3158.
(39) Hughes, R. P.; Lindner, D. C.; Liable-Sands, L. M.; Rheingold,
A. L. Organometallics 2001, 20, 363.
(40) Oliver, A. J.; Graham, W. A. G. Inorg. Chem. 1971, 10, 1165.
(41) Bowden, A. A.; Hughes, R. P.; Lindner, D. C.; Incarvito, C. D.;
Liable-Sands, L. M.; Rheingold, A. L. J. Chem. Soc., Dalton Trans. 2002,
3245.
(42) Hughes, R. P.; Maddock, S. M.; Guzei, I. A.; Liable-Sands, L. M.;
Rheingold, A. L. J. Am. Chem. Soc. 2001, 123, 3279.
(43) Hughes, R. P.; Maddock, S. M.; Rheingold, A. L.; Liable-Sands,
L. M. J. Am. Chem. Soc. 1997, 119, 5988.
(44) Kunicki, A. R.; Isobe, K.; Maitlis, P. M. J. Organomet. Chem.
1990, 399, 199.
(45) Corkey, B. K.; Taw, F. L.; Bergman, R. G.; Brookhart, M.
Polyhedron 2004, 23, 2943.
(46) Monti, D.; Bassetti, M.; Sunley, G. J.; Ellis, P.; Maitlis, P.
Organometallics 1991, 10, 4015.
(47) Churchill, M. R.; Julis, S. A. Inorg. Chem. 1979, 18, 2918.
(48) Churchill, M. R.; Julis, S. A. Inorg. Chem. 1979, 18, 1215.
(49) Yuan, J.; Hughes, R. P.; Golen, J. A.; Rheingold, A. L.
Organometallics 2010, 29, 1942.
(50) Yuan, J.; Hughes, R. P.; Rheingold, A. L. Inorg. Chim. Acta 2010,
364, 96.
(51) The chemical environment of the proton and fluorine nuclei
should be very similar for both diastereomers because the stereogenic
centers are far away from each other and separated from the metal by a
1,2-ethylene chain.
(52) Hughes, R. P.; Kovacik, I.; Lindner, D. C.; Smith, J. M.;
Willemsen, S.; Zhang, D.; Guzei, I. A.; Rheingold, A. L. Organometallics
2001, 20, 3190.
(53) Shenderovich, I. G.; Limbach, H.-H.; Smirnov, S. N.; Tolstoy,
P. M.; Denisov, G. S.; Golubev, N. S. Phys. Chem. Chem. Phys. 2002, 4,
5488.
(54) Christe, K. O.; Wilson, W. W. J. Fluorine Chem. 1990, 46, 339.
(55) Brownstein, S. Can. J. Chem. 1980, 58, 1407.
(56) Cambridge Structural Database search, version 5.32, Nov. 2010.
(57) Kirsch, P. Modern Fluoroorganic Chemistry; Wiley-VCH:
Weinheim, 2004.
(58) Cabot, R.; Hunter, C. A. Chem. Commun. 2009, 2005.
(59) Wakselman, C.; Lantz, A. In Organofluorine Chemistry. Principles
and Commercial Applications; Banks, R. E., Smart, B. E., Tatlow, J. C.,
Eds.; Plenum Press: New York, 1994; p 177.
(60) Cavallotti, C.; Metrangolo, P.; Meyer, F.; Recupero, F.; Resnati,
G. J. Phys. Chem. A 2008, 112, 9911.
(61) Hughes, R. P.; Larichev, R. B.; Zakharov, L. N.; Rheingold, A. L.
Organometallics 2005, 24, 4845.
(62) Wakselman, C. J. Fluorine Chem. 1992, 59, 367.
(63) Wu, F.; Xiao, F.; Yang, X.; Shen, Y.; Pan, T. Tetrahedron 2006,
62, 10091.
(64) Feiring, A. E. J. Org. Chem. 1985, 50, 3269.
(65) Toscano, P. J.; Barren, E. J. Chem. Soc., Chem. Commun. 1989,
1159.
(66) Blanksby, S. J.; Ellison, G. B. Acc. Chem. Res. 2003, 36, 255.
(67) These reactions were performed with in situ generated
complexes using a toluene solution of trimethylphosphine. If
perfluoroalkyl radicals were generated, they could abstract H from
toluene.
(68) Diversi, P.; Ingrosso, G.; Lucherini, A.; Martinelli, P.; Benetti,
M.; Pucci, S. J. Organomet. Chem. 1979, 165, 253.
(69) Jones, W. D.; Feher, F. J. Inorg. Chem. 1984, 23, 2376.
(70) Tedesco, V.; Philipsborn, W. Magn. Reson. Chem. 1996, 34, 373.
1298
dx.doi.org/10.1021/om2009588 | Organometallics 2012, 31, 1287−1299

Organometallics
Article
(71) Blancou, H.; Moreau, P.; Commeyras, A. Tetrahedron 1977, 33,
2061.
(72) Foris, A. Magn. Reson. Chem. 2004, 42, 534.
(73) Andreades, S. J. Am. Chem. Soc. 1964, 86, 2003.
(74) Johnson, S. A.; Taylor, E. T.; Cruise, S. J. Organometallics 2009,
28, 3842.
1299
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