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

Organometallics
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
dx.doi.org/10.1021/om2009588 | Organometallics 2012, 31, 1287−1299