Rhodium(I) acetylacetonato complexes with functionalized phosphines

Rhodium(I) complexes [Rh(acac)(CO)(PR3)] with 1,3,5-triaza-7-phosphatricyclo[3.3.1.1(3,7)]decane (tpa), tris(2-cyanoethyl)phosphine (cyep), tris(3-sodium sulfonatophenyl)phosphine (tppts), tris(o-methoxyphenyl)phosphine (ompp), tris(p-methoxyphenyl)phosphine (pmpp), tris(2,4,6-trimethoxyphenyl)phosphine (tmpp), PPh2(pyl), PPh(pyl)(2) and P(pyl)(3) (pyl = 2-pyridyl) have been synthesized and characterized with H-1- and P-31-NMR and IR spectra. The measured P-31 coordination chemical shifts, Delta delta(31)P{H-1}, correlate well with nu(CO). Differences in H-1 chemical shifts of methyl groups of acac ligand, Delta delta(Me), depend both on steric and electronic properties of phosphine ligand. Thus Delta delta(Me) increases with decrease of Delta delta(31)P{H-1} and increases with increase of the cone angle of phosphine. Catalytic activity of complexes with tpa, cyep and tppts has been investigated. They are efficient catalysts for hydrogenation of C=C and C=O bonds, isomerization of alkenes and hydroformylation of alkenes. The mechanism of isomerization of allyl alcohol to propanal has been elucidated. (C) 1998 Elsevier Science S.A. All rights reserved.