53513-14-7Relevant articles and documents
Reactions of bis(ditertiaryphosphine) complexes of rhodium(I) with carbon monoxide, dioxygen, dihydrogen, and hydrogen chloride
James, Brian R.,Mahajan, Devinder
, p. 996 - 1004 (2007/10/02)
The products, resulting from addition under mild conditions of the gaseous molecules CO, O2, H2, and HCl, to some rhodium(I)-bis(ditertiaryphosphine) complexes, are described; The P-P phosphines used were Ph2P(CH2)nPPh2, n=1-4, and (+)-diop (diop=2,3-O-isopropylidene 2,3-dihydroxy-1,4-bis(diphenylphosphino)butane).Monocarbonyls were isolated from addition of CO to RH(P-P)2+BF4- complexes (n=1 and 3), the reactions being reversible; there was no reaction with the n=2 system, while the n=4 and diop systems absorbed >1 mol of CO per Rh to give mixtures of products.The same cation precursors add O2 to yield cis-Rh(P-P)2O2+BF4- adducts (n=1-3), the binding being reversible for the n=2 system; pure products were not isolated with the n=4 cation which absorbs 3 mol O2/Rh; the diop system was unreactive toward O2.Reversible additions of 1 mol H2 yield isolable cis-H2Rh(P-P)2+BF4- complexes with the n=3 and diop systems; the n=1 and 2Rh(P-P)2+ cations are unreactive toward H2, while a mixture of hydrides is formed from the n=4 species.The chlorohydrido cations HRh(P-P)2Cl+A- (A=Cl, BF4, PF6, SbF6), n=1-3, were prepared via routes involving addition of gaseous HCl to precursor Rh(P-P)2Cl complexes; however, the reactions with the n=4 and diop systems did not yield pure products.The solution structures of all the isolated five- and six-coordinate addition products have been determined using 1H and variable temperature 31P nmr.The five-coordinate carbonyl with n=1 shows equivalent phosphines from -50 to 25 deg C, while the n=3 system shows inequivalent phosphines resulting from a trigonal bipyramidal structure with an equatorial carbonyl.The HRh(P-P)2Cl+ cation, n=3, has cis geometry, while trans-structures are preferred for the n=1 and 2 species.
