Chemical and x-ray structural properties of bis[bis(diphenylphosphino)methane]carbonylrhodium(I) tetrafluoroborate

Pignolet, L. H.; Doughty, D.H.; Nowicki, S. C.; Casalnuovo, A. L.

doi:10.1021/ic50209a068

Cited by 33 publications

(3 citation statements)

References 7 publications

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“…The CF 3 groups are in statistical disorder as observed also in other solid state structures of Rh−hfacac complexes 13b. Bond lengths and angles within the four-membered chelate , and within the hfacac ligand 13b are in the range expected from other Rh(I) complexes containing similar moieties. The coordination geometry about Rh is slightly distorted from an ideal square planar arrangement with an angle θ between the O−Rh−O and P−Rh−P planes of 12.6°.…”

Section: Resultssupporting

confidence: 68%

¹⁰³Rh Chemical Shifts in Complexes Bearing Chelating Bidentate Phosphine Ligands

et al. 1999

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Experimental and theoretical methods have been employed to investigate the influence of the chelating phosphine ligand on the 103Rh chemical shift in complexes containing the [(P2)Rh] fragment (P2 = chelating bidentate phosphine). The δ(103Rh) values obtained by 2D(31P,103Rh{1H}) NMR spectroscopy for a series of neutral rhodium complexes [{R2P(CH2) n PR2}Rh(hfacac)] (R = Ar, Ph, Cy, Me, n = 1−4, hfacac = hexafluoroacetylacetonate) have been compared. Systematic variation of the phosphine ligand has allowed separation of electronic and geometrical effects. The purely electronic influence of para substituents in complexes [{(p-XC6H4)2P(CH2)4P(p-XC6H4)2}Rh(hfacac)] correlates directly with the Hammett σP constants of X, but leads to variations in the chemical shift of less than 80 ppm between X = CF3 and X = OMe. In contrast, geometrical changes in complexes [(P2)Rh(hfacac)] lead to variations in the chemical shift over a range of approximately 800 ppm. The individual contributions of various structural parameters on the δ(103Rh) values have been assessed by density-functional-based calculations for suitable model compounds. The same approach has been extended to the rationalization of the trends in 103Rh chemical shifts of cationic complexes with four P donor ligands around a Rh(+I) center and selected anionic Rh(−I) complexes [(P2)2Rh]-. This analysis allows for the first time a direct corroboration of geometrical variations and their effect on 103Rh chemical shifts, demonstrating that correlations of reactivity with 103Rh chemical shifts can give valuable information on structure/reactivity relationships.

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Section: Resultssupporting

confidence: 68%

¹⁰³Rh Chemical Shifts in Complexes Bearing Chelating Bidentate Phosphine Ligands

et al. 1999

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“…23,48-50 These complexes possess different solid-state structures, ,, solution behavior, ,, and chemical reactivity, 20,22,52-54 as n is varied from 1 to 6. The reaction of these complexes with CO and with H 2 illustrates major reactivity differences. ,,,− Reversible addition of H 2 gave cis -[(H) 2 Rh(PPh 2 (CH 2 ) n PPh 2 ) 2 ] + with n = 3, while the n = 1 and 2 cationic rhodium precursors were unreactive toward H 2 and a mixture of hydrides was formed when n = 4 . The simple monocarbonyl adducts [Rh(PPh 2 (CH 2 ) n PPh 2 ) 2 CO] + were isolated for n = 1 and 3 53-55 and no CO adduct was formed for n = 2, while a mixture containing some binuclear DPPB-bridged complex [Rh 2 (PPh 2 (CH 2 ) 4 PPh 2 ) 3 (CO) 4 ] + was obtained when n = 4. , In addition, variable-temperature 31 P NMR data indicated that the geometry of [Rh(PPh 2 (CH 2 ) n PPh 2 ) 2 ] + cations in solution varied from square planar ( n = 2) to solvated trigonal bipyramidal with a solvent molecule occupying an equatorial position ( n = 3) and to unidentifiable, complicated species ( n = 4), although these complexes all possess the same general formula in the solid state (Chart ). ,,− “ A combination of solvated species and dimeric/polynuclear species ” was suggested by Anderson and Pignolet in the case of n = 4 …”

Section: Resultsmentioning

confidence: 99%

Interconversion between Zwitterionic and Cationic Rhodium(I) Complexes of Demonstrated Value as Catalysts in Hydroformylation, Silylformylation, and Hydrogenation Reactions. Dynamic³¹P{¹H} NMR Studies of (η⁶-PhBPh₃)^-Rh⁺(DPPB) and [Rh(DPPB)₂]⁺BPh₄^-in Solution

et al. 1996

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Treatment of an orange solution of [Rh(COD)(DPPB)] + BF 4 -(2) in MeOH with 2 equiv of NaBPh 4 at room temperature (RT) afforded an orange precipitate, [Rh(COD)(DPPB)] + BPh 4 -(3), in 94% yield. Reaction of the cationic rhodium complex 3 with H 2 under ambient conditions in CH 2 Cl 2 for 1 h gave the zwitterionic complex (η 6 -PhBPh 3 ) -Rh + (DPPB) (4) in quantitative yield. Although 3 is stable in the solid state, it has the propensity in solution to convert to the zwitterionic complexes (η 6 -PhBPh 3 ) -Rh + (COD) (1) and (η 6 -PhBPh 3 ) -Rh + -(DPPB) (4) along with a small amount of [Rh x (DPPB) 2x ] x+ [BPh 4 -] x . Addition of 1, 2, and 4 equiv of DPPB to the CD 2 Cl 2 solution of (η 6 -PhBPh 3 ) -Rh + (NBD) (6) under N 2 resulted in the formation of [Rh(NBD)(DPPB)] + BPh 4 -(7) and [Rh(DPPB) 2 ] + BPh 4 -(5) in ratios of 90/ 10, 57/43, and 0/100, respectively, while addition of 2 equiv of DPPB to the CD 2 Cl 2 solution of 6, under an atmosphere of H 2 at RT, gave 4 and 5 in an ratio of 35/65. "Slowed" η 6 -PhBPh 3 -rotation about the (η 6 -PhBPh 3 ) --Rh bond axis in (η 6 -PhBPh 3 ) -Rh + (DPPB) (4) was established by a variable-temperature 31 P{ 1 H} NMR study. Variable-temperature 31 P{ 1 H} NMR spectra of [Rh(DPPB) 2 ] + BPh 4 -(5) along with the low-temperature 31 P{ 1 H} COSY and EXSY NMR spectra demonstrated the presence of an equilibrium between [Rh(DPPB) 2 ] + (5R) and [Rh(DPPB)(µ-DPPB)] 2 2 + (5 ).

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“…The former has produced several new Co(0) complexes (18) along with [C~(CO)(Diphos)~lX (X = BH3CN, BPh4) 6 . This compound, 6 (X = ClO,) has previously been characterized (5,19), as have related Rh (20) and Ir (21) is formed as the ethanol solvate (Scheme 1). This reacts with NaBPh4 to form 7 (X = BPh4).…”

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confidence: 89%

Reactions between Co(II), 1,2-bis(diphenylphosphino)ethane, and NaBH₃CN in the presence and absence of CO. The crystal structure of bis(cyanotrihydroborato)tetrakis(N,N-dimethylformamide)cobalt(II)

Elliot¹,

Haukilahti²,

Holah³

et al. 1988

Can. J. Chem.

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Reactions between Co(II), Diphos, and NaBH3CN lead to Co(BH3CN)2(Diphos)2, 1, or [Co(BH3CN)(Diphos)2]X, 2 (X = ClO4 or BPh4), and, in certain solvents, 2 reacts to produce [Co(CN)(Diphos)2](ClO4). Compound 1 can be reversibly converted to Co(BH3CN)2(DMF)4, 4, via Co(BH3CN)2(Diphos)(DMF). In addition, 1 reacts with CO to form the Co(I) and Co(III) compounds [Co(Diphos)2](CO)]X and [Co(Diphos)2(CN)2]X (X = BH3CN or BPh4). Single crystal X-ray diffraction studies of 4 show that the compound crystallizes in the triclinic space group [Formula: see text], with unit cell parameters a = 7.572(6), b = 9.695(6), c = 9.395(6) Å, α = 81.06(4), β = 68.46(5), γ = 68.19(5)°, V = 595.5 Å3, Z = 1, and dcalcd = 1.202 g cm−3. The structure converged to a conventional R factor of 0.040 for 2841 observations and showed an octahedral arrangement of four O atoms from DMF molecules and two trans N-bound BH3CN groups around the Co(II) center.

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Chemical and x-ray structural properties of bis[bis(diphenylphosphino)methane]carbonylrhodium(I) tetrafluoroborate

Cited by 33 publications

References 7 publications

¹⁰³Rh Chemical Shifts in Complexes Bearing Chelating Bidentate Phosphine Ligands

¹⁰³Rh Chemical Shifts in Complexes Bearing Chelating Bidentate Phosphine Ligands

Interconversion between Zwitterionic and Cationic Rhodium(I) Complexes of Demonstrated Value as Catalysts in Hydroformylation, Silylformylation, and Hydrogenation Reactions. Dynamic³¹P{¹H} NMR Studies of (η⁶-PhBPh₃)^-Rh⁺(DPPB) and [Rh(DPPB)₂]⁺BPh₄^-in Solution

Reactions between Co(II), 1,2-bis(diphenylphosphino)ethane, and NaBH₃CN in the presence and absence of CO. The crystal structure of bis(cyanotrihydroborato)tetrakis(N,N-dimethylformamide)cobalt(II)

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Chemical and x-ray structural properties of bis[bis(diphenylphosphino)methane]carbonylrhodium(I) tetrafluoroborate

Cited by 33 publications

References 7 publications

103Rh Chemical Shifts in Complexes Bearing Chelating Bidentate Phosphine Ligands

103Rh Chemical Shifts in Complexes Bearing Chelating Bidentate Phosphine Ligands

Interconversion between Zwitterionic and Cationic Rhodium(I) Complexes of Demonstrated Value as Catalysts in Hydroformylation, Silylformylation, and Hydrogenation Reactions. Dynamic31P{1H} NMR Studies of (η6-PhBPh3)-Rh+(DPPB) and [Rh(DPPB)2]+BPh4-in Solution

Reactions between Co(II), 1,2-bis(diphenylphosphino)ethane, and NaBH3CN in the presence and absence of CO. The crystal structure of bis(cyanotrihydroborato)tetrakis(N,N-dimethylformamide)cobalt(II)

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¹⁰³Rh Chemical Shifts in Complexes Bearing Chelating Bidentate Phosphine Ligands

¹⁰³Rh Chemical Shifts in Complexes Bearing Chelating Bidentate Phosphine Ligands

Interconversion between Zwitterionic and Cationic Rhodium(I) Complexes of Demonstrated Value as Catalysts in Hydroformylation, Silylformylation, and Hydrogenation Reactions. Dynamic³¹P{¹H} NMR Studies of (η⁶-PhBPh₃)^-Rh⁺(DPPB) and [Rh(DPPB)₂]⁺BPh₄^-in Solution

Reactions between Co(II), 1,2-bis(diphenylphosphino)ethane, and NaBH₃CN in the presence and absence of CO. The crystal structure of bis(cyanotrihydroborato)tetrakis(N,N-dimethylformamide)cobalt(II)