Inorganic Chemistry
ARTICLE
(d) P,P0-1,2-bis(Diphenylphosphino)ethane(P,N-diphenyl(o-N-
methylanilido)phosphine)rhodium(I), [Rh(P,P0-dppe)(P,N-Ph2PArꢀ)]
(3). In a 50 mL Schlenk flask under anhydrous conditions and Ar
atmosphere, dppe (71 mg, 178 μmol) and [Rh(COD)(P,N-Ph2PArꢀ)]
(1a, 103 mg, 178 μmol) were dissolved in 7 mL of tetrahydrofuran at
ambient temperature producing a red solution, which was stirred for
10 min. Stirring was stopped, the solution was carefully layered with
20 mL of n-pentane, and the mixture was left undisturbed for 18 h. The
supernatant was removed by cannula transfer under Ar, then the solid
was dried in vacuo and recovered as large red crystals (103 mg, 79%
yield, found: C, 68.17; H, 5.70; N, 1.73%. Calcd for [C45H41-
5 min. Stirring was stopped, the solution was carefully layered with 10 mL
of n-pentane, and the mixture was left undisturbed for 18 h. The super-
natant was removed by cannula transfer under Ar; then the solid was
dried in vacuo and recovered as large orange crystals (134 mg, 71% yield,
found: C, 53.89; H, 4.89; N, 2.34%. Calcd for [C27H28NPRh][BF4]
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0.25CH2Cl2: C, 53.79; H, 4.72; N, 2.30%). 1H NMR analysis in CDCl3
(obtained at approximately the same time as the elemental analysis) was
used to verify dichloromethane content. HRMS (ESI): m/z 500.1003
[M]þ. Calcd for C27H28NPRh: m/z 500.1009.
(i) η2:η2-1,4-Norbornadiene(P,N-di(o-N,N-dimethylanilinyl)phenylphos-
phine)rhodium(I) Tetrafluoroborate, [Rh(NBD)(P,N-PhPAr02)][BF4] (7b).
The compound was prepared in a manner similar to that of 7a using PhPAr02
(153 mg, 439 μmol) and [Rh(NBD)2][BF4] (164 mg, 439 μmol) and was
isolated as a yellow-orange powder (231 mg, 83% yield, found: C, 55.42; H,
5.35; N, 4.37%. Calcd for [C29H33N2PRh][BF4]: C, 55.26; H, 5.28; N,
4.44%). HRMS (ESI): m/z 543.1425 [M]þ. Calcd for C29H33N2PRh: m/z
543.1431.
NP3Rh] C4H8O: C, 68.14; H, 5.72; N, 1.62%). Single crystals suitable
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for X-ray diffraction were obtained by slow evaporation from a tetra-
hydrofuran solution in an NMR tube.
(e) η2-Peroxo(P,P0-1,2-bis(diphenylphosphino)ethane)(P,N-diphenyl-
(o-N-methylanilido)phosphine)rhodium(III), [RhO2(P,P0-dppe)(P,N-
Ph2PArꢀ)] (4). In a 50 mL Schlenk flask under anhydrous conditions
and Ar atmosphere, 10 mL of tetrahydrofuran was added to [Rh(P,P0-
dppe)(P,N-Ph2PArꢀ)] (3, 31 mg, 36 μmol), and the mixture was stirred
for 30 min resulting in a bright red solution. Oxygen was passed through
the solution for 10 min with no noticeable color change, and 20 mL of
n-pentane was then added resulting in an orange slurry, which was stirred
for 30 min before allowing the precipitate to settle. The supernatant was
removed by cannula transfer, and the red solid was then dried in vacuo
(25 mg, 68% yield. HRMS (ESI): m/z 824.1473 [M þ H]þ. Calcd for
C45H42NO2P3Rh: 824.1478). Single crystals suitable for X-ray diffrac-
tion were obtained by slow evaporation from a benzene solution in an
NMR tube.
(j)
bis(η2:η2-1,4-Norbornadiene)(μ-P,N,P0,N0-bis(di(o-N,N-dimethyl-
anilinyl)phosphino)methane)dirhodium(I,I) Bis(tetrafluoroborate), [Rh2-
(NBD)2(μ-P,N,P0,N0-dmapm)][BF4]2 (8). In a 50 mL Schlenk tube under
anhydrous conditions and Ar atmosphere, dmapm (225 mg, 404 μmol)
and [Rh(NBD)2][BF4] (302 mg, 808 μmol) were dissolved in 10 mL of
dichloromethane at ambient temperature resulting in an orange-red
solution, which was then stirred for 5 min. To the stirred solution was added
20 mL of n-pentane resulting in the formation of a yellow precipitate. The
slurry was stirred for 5 min before allowing the precipitate the settle. The
supernatant was then removed by cannula transfer under Ar, and the
product was isolated as a yellow powder (414 mg, 85% yield, found: C,
(f) Iodo(methyl)(P,P0-1,2-bis(diphenylphosphino)ethane)(P,N-di-
phenyl(o-N-methylanilido)phosphine)rhodium(III), [RhI(CH3)(P,P0-
dppe)(P,N-Ph2PArꢀ)] (5). In a 50 mL Schlenk flask under anhydrous
conditions and Ar atmosphere, [Rh(COD)(P,N-Ph2PArꢀ)] (1a,
157 mg, 271 μmol) and dppe (108 mg, 271 μmol) were dissolved in
10 mL of benzene at ambient temperature while stirring. Iodomethane
(17 μL, 270 μmol) was then added via microsyringe resulting in an
instantly noticeable darkening of the solution color. The solvent volume
was reduced to approx 5 mL in vacuo, and 20 mL of diethyl ether was
added while stirring to produce a red precipitate. The precipitate was
allowed to settle from the mixture, and the supernatant was removed by
cannula under Ar. The solid was dried in vacuo and isolated as a red
powder (152 mg, 49% yield, found: C, 58.78; H, 5.13; N, 1.35%. Calcd
for [C46H44INP3Rh]: C, 59.18; H, 4.75; N, 1.50%). Although the crystal
structure indicates 1 equiv of C4H10O and 2 equiv of C4H8O per formula
48.94; H, 5.10; N, 4.58%. Calcd for [C47H58N4P2Rh2][BF4]2 0.5CH2Cl2:
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C, 49.06; H, 5.11; N, 4.82%). Although the crystal structure indicates 1
equiv of CH2Cl2 per formula unit, a noncrystalline sample was analyzed
here, which was exposed to air before analysis. 1H NMR analysis in CDCl3
(obtained at approximately the same time as the elemental analysis) was
used to verify dichloromethane content. Single crystals suitable for X-ray
diffraction were obtained by layering a saturated dichloromethane solution
with tetrahydrofuran in an NMR tube. HRMS (ESI): m/z 473.1117
[M]2þ. Calcd for C47H58N4P2Rh2: m/z 473.1118.
(k) η2:η2-1,5-Cyclooctadiene(P,N-diphenyl(o-N-methylanilinyl)-
phosphine)rhodium(I) Trifluoromethanesulfonate, [Rh(COD)(P,N-
Ph2PAr)][OTf] (9). In a 25 mL Schlenk tube under anhydrous conditions
and Ar atmosphere, [Rh(COD)(P,N-Ph2PArꢀ)] (1a, 100 mg, 173 μmol)
was dissolved in 2 mL of dichloromethane at ambient temperature
producing an orange-red solution. While stirring, HOTf (16 μL,
180 μmol) was added, which turned the solution yellow after 5 min. To
the stirred solution, 10 mL of n-pentane was added resulting in the
formation of a yellow precipitate. Stirring was stopped, the precipitate was
allowed to settle and the supernatant was removed by cannula transfer
under Ar. The solid was then dried in vacuo and isolated as a yellow
powder (76 mg, 63% yield, found: C, 49.36; H, 4.33; N, 2.14%. Calcd for
1
unit, a noncrystalline sample was analyzed here. H NMR analysis in
C6D6 (obtained at approximately the same time as the elemental
analysis) was used to verify solvent content. Single crystals suitable for
X-ray diffraction were obtained by layering a saturated tetrahydrofuran
solution with diethyl ether in an NMR tube.
(g) P,P0-1,2-bis(Diphenylphosphino)ethane(P,N-diphenyl(o-N,N-
dimethylanilinyl)phosphine)rhodium(I) Tetrafluoroborate, [Rh(P,P0-
dppe)(P,N-Ph2PAr0)][BF4] (6). In an NMR tube under Ar atmosphere,
[Rh(P,P0-dppe)(P,N-Ph2PArꢀ)] (3, 21 mg, 24 μmol) and Me3OBF4
(4.0 mg, 27 μmol) were dissolved in 0.7 mL of CD3NO2 producing a
dark yellow solution. 31P{1H} and 1H NMR spectra reveal 6 as the major
product along with [Rh(P,P0-dppe)(P,N-Ph2PAr)][BF4], suggesting the
presence of moisture in the reaction mixture (generating HBF4, which
protonates at nitrogen). Despite our best efforts, we have not been able
to isolate 6 as an analytically pure substance.
[C27H30NPRh][CF3O3S] 0.5CH2Cl2: C, 49.33; H, 4.50; N, 2.02%). 1H
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NMR analysis in CDCl3 (obtained at approximately the same time as the
elemental analysis) was used to verify dichloromethane content. Single
crystals suitable for X-ray diffraction were obtained by slow evaporation
from a dichloromethane solution in an NMR tube. HRMS (ESI): m/z
502.1170 [M]þ. Calcd for C27H30NPRh: 502.1165.
Low Temperature Protonation of [Rh(P,P0-dppe)(P,N-Ph2-
PArꢀ)] (3). In an NMR tube under anhydrous conditions and Ar
atmosphere, 3 (25 mg, 29 μmol) was dissolved in 0.7 mL of CD2Cl2 at
ambient temperature, and the bright red solution was immediately
(h) η2:η2-1,4-Norbornadiene(P,N-diphenyl(o-N,N-dimethylanilinyl)-
phosphine)rhodium(I) Tetrafluoroborate, [Rh(NBD)(P,N-Ph2PAr0)]-
[BF4] (7a). In a 50 mL Schlenk flask under anhydrous conditions and Ar
atmosphere, Ph2PAr0 (94 mg, 308 μmol) and [Rh(NBD)2][BF4]
(115 mg, 308 μmol) were dissolved in 5 mL of dichloromethane at
ambient temperature resulting in an orange solution, which was stirred for
cooled to ꢀ80 °C in acetone/dry ice. Using a microsyringe, HBF4 Et2O
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(4.0 μL, 29 μmol) was added, resulting in a brilliant blue-green solution,
and the temperature of the tube was maintained at ꢀ80 °C throughout
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the duration of subsequent H, H{31P} and 31P{1H} NMR analyses
(approximately 5 min).
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dx.doi.org/10.1021/ic101883u |Inorg. Chem. 2011, 50, 5361–5378