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

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