31781-57-4Relevant articles and documents
Slow exchange of bidentate ligands between rhodium(I) complexes: Evidence of both neutral and anionic ligand exchange
Chen, Si,Manoury, Eric,Poli, Rinaldo
supporting information, p. 5820 - 5826 (2015/02/19)
The phosphine double exchange process involving [RhCl(COD)(TPP)] and [Rh(acac)(CO)(TMOPP)] (TPP = PPh3, TMOPP = P(C6H4-4-OMe)3) to yield [RhCl(COD)(TMOPP)] and [Rh(acac)(CO)(TPP)] is very rapid but is followed by a much slower process where the bidentate ligands are exchanged to yield [Rh(acac)(COD)] and a mixture of [RhCl(CO)(TPP)2], [RhCl(CO)(TMOPP)2], and [RhCl(CO)(TPP)(TMOPP)]. The exchange involving [RhCl(COD)(L)] and [Rh(acac)(CO)(L)] yields [Rh(acac)(COD)] and [RhCl(CO)(L)2], where the reaction is much faster when L = TPP than when L = TMOPP. The mixed-metal system comprising [IrCl(COD)(TPP)] and [Rh(acac)(CO)(TPP)] yields all four complexes [M(acac)(COD)] and [MCl(CO)(TPP)2], where M = Rh and Ir. This illustrates that both a neutral ligand exchange and an anionic ligand exchange occur. Possible pathways for these processes are discussed.
Cooperative double deprotonation of bis(2-picolyl)amine leading to unexpected bimetallic mixed valence (M-I, MI) rhodium and iridium complexes
Tejel, Cristina,Del Rio, M. Pilar,Asensio, Laura,Van Den Bruele, Fieke J.,Ciriano, Miguel A.,Tsichlis I Spithas, Nearchos,Hetterscheid, Dennis G. H.,De Bruin, Bas
, p. 7524 - 7534 (2011/10/03)
Cooperative reductive double deprotonation of the complex [Rh I(bpa)(cod)]+ ([4]+, bpa = PyCH 2NHCH2Py) with one molar equivalent of base produces the bimetallic species [(cod)Rh(bpa-2H)Rh(cod)] (7), which displays a large Rh -I,RhI contribution to its electronic structure. The doubly deprotonated ligand in 7 hosts the two "Rh(cod)" fragments in two distinct compartments: a "square planar compartment" consisting of one of the Py donors and the central nitrogen donor and a "tetrahedral π-imine compartment" consisting of the other pyridine and an "imine C=N" donor. The formation of an "imine donor" in this process is the result of substantial electron transfer from the {bpa-2H}2- ligand to one of the rhodium centers to form the neutral imine ligand bpi (bpi = PyCH2N=CHPy). Hence, deprotonation of [RhI(bpa)(cod)] + represents a reductive process, effectively leading to a reduction of the metal oxidation state from RhI to Rh-I. The dinuclear iridium counterpart, complex 8, can also be prepared, but it is unstable in the presence of 1 mol equiv of the free bpa ligand, leading to quantitative formation of the neutral amido mononuclear compound [Ir I(bpa-H)(cod)] (2). All attempts to prepare the rhodium analog of 2 failed and led to the spontaneous formation of 7. The thermodynamic differences are readily explained by a lower stability of the M-I oxidation state for iridium as compared to rhodium. The observed reductive double deprotonation leads to the formation of unusual structures and unexpected reactivity, which underlines the general importance of "redox noninnocent ligands" and their substantial effect on the electronic structure of transition metals.
Formation of a phosphine-phosphinite ligand in RhCl(PRR′2) [P,P-R′(R)POCH2P(CH2OH)2] and R′H from cis-RhCl(PRR′2)2[P(CH2OH) 3] via P-C bond cleavage
Lorenzini, Fabio,Patrick, Brian O.,James, Brian R.
, p. 8998 - 9002 (2008/10/09)
Reaction of RhCl(1,5-cod)(THP), where THP = P(CH2OH) 3, with several PRR′2 phosphines (R = or ≠ R′) generates, concomitantly with R′H, the derivatives RhCl(PRR′2)[P,P-R′(R)POCH2P(CH 2OH)2] in two isomeric forms. The hydrogen of the hydrocarbon co-product derives from a THP hydroxyl group which becomes an 'alkoxy' group at the residual PRR' moiety, this resulting in the P,P-chelated R′(R)POCH2P(CH2OH)2 ligand. One of the isomers of the PPh3 system, cis-RhCl(PPh3)[P, P-P(Ph) 2OCH2P(CH2OH)2], was structurally characterized (cis refers to the disposition of the P atoms with Ph substituents).
