Some cationic carbonyl complexes of rhodium(I)

Reddy, G.K.N.; Ramesh, Balu

doi:10.1016/s0022-328x(00)88191-7

Cited by 26 publications

(6 citation statements)

References 8 publications

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“…The IR spectrum of 6 displays two carbonyl stretching frequencies at 2004 and 2067 cm -1 and these values are lower than those associated with the related complex [(bipy)Rh-(CO) 2 ]ClO 4 (2050, 2108 cm -1 ). 53 Similarly, the carbonyl stretching frequencies for 7 (1986 and 2050 cm -1 ) are at lower frequencies than those for [(bipy)Ir(CO) 2 ]ClO 4 (2024, 2089 cm -1 ). 54 The lower frequency carbonyl stretches of 6 and 7 might reflect more electron-donating properties for PyPyr (vs bipy), but this difference may also be primarily attributed to the difference in charge on the complexes.…”

Section: Resultsmentioning

confidence: 87%

High Oxidation State Rhodium and Iridium Bis(silyl)dihydride Complexes Supported by a Chelating Pyridyl-Pyrrolide Ligand

2009

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New rhodium and iridium complexes containing the bidentate ligand 3,5-diphenyl-2-(2-pyridyl)pyrrolide (PyPyr) were prepared. The bis(ethylene) complex (PyPyr)Rh(C(2)H(4))(2) (3) reacted with HSiEt(3), HSiPh(3), and HSi(t)BuPh(2) to produce the 16-electron Rh(V) bis(silyl)dihydrides (PyPyr)Rh(H)(2)(SiEt(3))(2) (8), (PyPyr)Rh(H)(2)(SiPh(3))(2) (9), and (PyPyr)Rh(H)(2)(Si(t)BuPh(2))(2) (10), respectively. The analogous Ir(V) bis(silyl)dihyride (PyPyr)Ir(H)(2)(SiPh(3))(2) (11) has also been synthesized. X-ray crystallography reveals that 9-11 adopt a coordination geometry best described as a bicapped tetrahedron. Silane elimination from 9 and 10 occurred in the presence of either HSiEt(3) or PPh(3). Mechanistic studies of the silane exchange process involving 10 and free HSiEt(3) (to give 8) indicate that this process occurs by rate-limiting reductive elimination of HSi(t)BuPh(2) from 10 to generate a 14-electron Rh(III) intermediate of the type (PyPyr)Rh(H)(Si(t)BuPh(2)).

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Section: Resultsmentioning

confidence: 87%

High Oxidation State Rhodium and Iridium Bis(silyl)dihydride Complexes Supported by a Chelating Pyridyl-Pyrrolide Ligand

2009

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“…For example, K[PyInd] reacted with [(CO) 2 RhCl] 2 at room temperature in benzene to give (PyInd)Rh(CO) 2 ( 1 ) in 76% yield (eq 1) after extraction with CH 2 Cl 2 and crystallization from a CH 2 Cl 2 /pentane mixture. The IR spectrum of 1 contains two carbonyl stretching frequencies at 2054 and 1999 cm -1 , which may reflect slightly greater π-back-bonding in this neutral complex relative to the cationic analogue [(bpy)Rh(CO) 2 ] + (ν CO at 2080 and 2010 cm -1 ) …”

Section: Resultsmentioning

confidence: 99%

Stoichiometric and Catalytic Reactions Involving Si−H Bond Activations by Rh and Ir Complexes Containing a Pyridylindolide Ligand

2006

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New rhodium and iridium complexes containing the bidentate, monoanionic 2-(2′-pyridyl)indolide (PyInd) ligand were prepared. The bis(ethylene) complex (PyInd)Rh(C 2 H 4 ) 2 (3) reacted with triethylsilane at 60 °C to produce the 16-electron Rh(V) bis(silyl)dihydride complex (PyInd)RhH 2 (SiEt 3 ) 2 (4). Both 3 and 4 catalyzed the chloride transfer reaction of chlorobenzene and Et 3 SiH to give Et 3 SiCl and benzene in the absence of base. In the presence of LiN i Pr 2 , catalytic C-Si coupling was observed, to produce Et 3 SiPh. Analogous Ir complexes of the type (PyInd)IrH 2 (SiR 3 ) 2 , where R 3 ) Et 3 (6a), Me 2 Ph (6b), Ph 2 Me (6c), or Ph 3 (6d), were not catalytically active in this chloride transfer chemistry. The molecular structure of 6c, determined by X-ray crystallography, may be described as having a highly unusual bicapped tetrahedral geometry. DFT calculations indicate that this distortion is associated with the d 4 electron count and the presence of highly trans-influencing silyl ligands. The reaction of 6a with PMe 3 (5 equiv) produced (PyInd)IrH(SiEt 3 )(PMe 3 ) 2 (7), while the reaction with PPh 3 (1 equiv) generated a mixture of isomers that was converted to (PyInd)IrH(SiEt 3 )(PPh 3 ) (8) upon heating in benzene at 80 °C. Complexes 7 and 8 exhibit regular octahedral and distorted square pyramidal geometries, respectively.

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“…Both electronic and steric factors are involved in the equi- While Rh(CO)2L3+ complexes have configuration 47 in solution (two carbonyl bands in the IR) when L = PMePh2 or As-MePh2, they have 48 when L = P(p-Tol)3, PPh3, AsPrPh2, or AsPh3. 148 Attempts to prepare a tris phosphine complex with P(o-Tol)3 failed, giving only 49. The isomer distribution in eq 16 (L = PR3, AsR3, or SbR3) depends on both steric and electronic effects. 149 Equilibria shift to the right in the series R = Me < Et ~Pr ~Bu < n-pentyl < n-octyl < isopentyl < aBu < sec-alkyl, SbR3 < AsR3 < PR3, and X = CF3 < Br < F ~H < Me < OMe when L = AsEt2(p-C6H4X).…”

Section: Table XLVII Equilibrium Constantsmentioning

confidence: 99%

Steric effects of phosphorus ligands in organometallic chemistry and homogeneous catalysis

Tolman¹

1977

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Some cationic carbonyl complexes of rhodium(I)

Cited by 26 publications

References 8 publications

High Oxidation State Rhodium and Iridium Bis(silyl)dihydride Complexes Supported by a Chelating Pyridyl-Pyrrolide Ligand

High Oxidation State Rhodium and Iridium Bis(silyl)dihydride Complexes Supported by a Chelating Pyridyl-Pyrrolide Ligand

Stoichiometric and Catalytic Reactions Involving Si−H Bond Activations by Rh and Ir Complexes Containing a Pyridylindolide Ligand

Steric effects of phosphorus ligands in organometallic chemistry and homogeneous catalysis

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