Dynamic coordinative exchange in rhodium(I) complexes of chiral diphosphines bearing pendant pyridyl donor groups

Bookham, Jonathan L.; Smithies, Darren M.; Pett, Mark Thornton

doi:10.1039/a908984e

Cited by 13 publications

(9 citation statements)

References 21 publications

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“…The use of weakly bonded olefins as leaving groups is wide‐spread for rhodium catalysts 26. The M–C distances in 1 and 14 are located within the typical range of 2.1–2.3 Å 15,17,18,27. However, the significantly longer mean value of the M–centroid distances in 1 than in 14 nicely corresponds to the fact that cod is easily displaced in the case of 1 , whereas difficulties appear using 14 as a precursor complex as a result of the five‐coordinate species that still contains cod.…”

Section: Resultsmentioning

confidence: 99%

The Influence of Steric Pressure on the Structure of Homodimetallic Rhodium(I) and Iridium(I) Complexes Containing a Bis(bidentate) Phosphane Ligand

et al. 2007

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P{ 1 H}), mass spectrometry, IR spectroscopy, elemental analyses and melting points. Furthermore, the solid-state structures of seven of these new compounds were fully determined by single-crystal X-ray diffraction analyses to study the influence of steric pressure. The precursor complex [Rh 2 (η 4 -cod) 2 (dppcb)]X 2 (1), X -= BF 4 -, PF 6 -, SbF 6 -, completely characterized by its X-ray structure, smoothly reacts with mono-or bidentate ligands containing phosphorus or nitrogen donor atoms. Thus, monophosphanes and monophosphites produce compounds of the structure type [Rh 2 L 4 (dppcb)](SbF 6 ) 2 [L = PMe 2 Ph, 2; PMePh 2 , 3; P(OMe) 3 , 5; P(OPh) 3 , 6]. The X-ray structures of 3 and 6 show that PMePh 2 and P(OPh) 3 are capable of compensating steric interactions. The treatment of 1 with diphosphanes leads to the structure type [Rh 2 L 2 (dppcb)](SbF 6 ) 2 [L = bis(diphosphanyl)-methane, dppm, 7; bis(diphenylphosphanyl)amine, dppam, 8; 1,2-bis(diphenylphosphanyl)ethane, dppe, 9; cis-1,2-

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Section: Resultsmentioning

confidence: 99%

The Influence of Steric Pressure on the Structure of Homodimetallic Rhodium(I) and Iridium(I) Complexes Containing a Bis(bidentate) Phosphane Ligand

et al. 2007

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“…Furthermore, there is considerable current interest in hybrid P/N ligands and a search in the Cambridge Structure Database revealed that although a vast number of Groups 9-10 complexes with nitrogen and phosphorus ligands have been characterised structurally, only a relatively small number of Pd(II) cations and Rh(I) cations [54][55][56][57][58][59][60][61][62][63][64][65] containing bidentate N(sp 2 )-P(sp 3 ) donors are reported. Since bulky substituents at the aryl groups of N(sp 2 ) donors have been found to strongly influence the catalytic activity and selectivity of Group 10 complexes [66], it is surprising that no Rh(I) complexes of ligands combining tertiary phosphine donors and (sp 2 )N-aryl donors with bulky ortho substituents have been structurally investigated.…”

Section: Introductionmentioning

confidence: 99%

New cationic palladium (II) and rhodium (I) complexes of [Ph2PCH2C(Ph)N(2,6-Me2C6H3)]

Pascu

Coleman

Cowley

et al. 2005

Journal of Organometallic Chemistry

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“…shows a similar P,P',N and P,P',N' exchange for a Rh(I) complex. 22 Also notable is the behavior of It has been reported that rhodium catalysts containing achiral -aminophosphines have a greater activity when the ligand bears an ether vs an alcohol function. 8 The preparation of a P,N,N ligand with a chiral -amino-phosphine moiety has not so far been considered.…”

Section: Introductionmentioning

confidence: 99%

Synthesis, Coordination to Rh(I), and Hydroformylation Catalysis of New β-Aminophosphines Bearing a Dangling Nitrogen Group: An Unusual Inversion of a Rh-Coordinated P Center

et al. 2002

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Variants of the beta-aminophosphine L(1) [Ph(2)PCH(2)CH(Ph)NHPh] containing additional nitrogen donor functions have been prepared. These functions are branched off the C atom adjacent to the P atom, or the P atom itself. Ligand [Ph(2)PCH(o-C(6)H(4)NMe(2))CH(Ph)NHPh] has been obtained as a mixture of two diastereomers L(3A) and L(3B) by lithiation of L(2) [Ph(2)PCH(2)(o-C(6)H(4)NMe(2))] with n-BuLi followed by PhCH=NPh addition and hydrolysis. The diastereomers have been separated by fractional crystallization from ethanol. Ligand Et(2)NCH(2)P(Ph)CH(2)CH(Ph)NHPh has been obtained as a mixture of two diastereomers L(5A) and L(5B)(starting with P-Ph reductive cleavage of L(1) by lithium and subsequent hydrolysis to give PhP(H)CH(2)CH(Ph)NHPh (mixture of two diastereomers L(4A) and L(4B)). The latter reacts with diethylamine and formaldehyde to afford the L(5) diastereomeric mixture. Complexes RhCl(CO)(L) (L = L(3A), 1(A); L(3B), 1(B); L(5A/B), 2(A/B)) were obtained by reaction of [RhCl(CO)(2)](2) and the appropriate ligand or ligand mixture. Complexes 1(A), 1(B), and 2(A) have been isolated in pure form and characterized by classical techniques and by single-crystal X-ray diffraction. All structures exhibit a bidentate kappa-P,kappa-N(NHPh) mode similar to the complex containing L(1). While complexes 1(A) or 1(B) are stable in CDCl(3) solution, complex 2(A) slowly converts to its diastereomer 2(B). This unexpected epimerization appears to take place by inversion at the Rh-coordinated P center, an apparently unprecedented phenomenon. A mechanism based on a reversible P-C bond oxidative addition is proposed. The influence of the pendant nitrogen function of the diaminophosphines L(3A) and L(5A/B) on the rhodium catalytic activity in styrene hydroformylation has been examined and compared to that of the aminophosphines L(1) or L(2). The observed trends are related to the basicity of the dangling amine function and to its proximity to the metal center.

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Dynamic coordinative exchange in rhodium(I) complexes of chiral diphosphines bearing pendant pyridyl donor groups

Cited by 13 publications

References 21 publications

The Influence of Steric Pressure on the Structure of Homodimetallic Rhodium(I) and Iridium(I) Complexes Containing a Bis(bidentate) Phosphane Ligand

The Influence of Steric Pressure on the Structure of Homodimetallic Rhodium(I) and Iridium(I) Complexes Containing a Bis(bidentate) Phosphane Ligand

New cationic palladium (II) and rhodium (I) complexes of [Ph2PCH2C(Ph)N(2,6-Me2C6H3)]

Synthesis, Coordination to Rh(I), and Hydroformylation Catalysis of New β-Aminophosphines Bearing a Dangling Nitrogen Group: An Unusual Inversion of a Rh-Coordinated P Center

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