(R,R)-Tricarbonyl{η6-1-(diphenylphosphino)-2-[1-(diphenylphosphino)ethyl]benzene}chromium(0), (R,R)-tricarbonyl-1κ3C-{μ-1(η6):2κ2P,P′-1-(diphenylphosphino)2-[1-(diphenylphosphino)ethyl]benzene}[2(η4)-norbornadiene]chromium(0)rhodium(I) tetrafluoroborate methanol 0.75-solvate and (R,R)-tricarbonyl-1κ3C-{μ-1(η6):2κ2P,P′-1-(diphenylphosphino)2-[1-(diphenylphosphino)ethyl]benzene}[2(η4)-(Z,Z)-cycloocta-1,5-diene]chromium(0)rhodium(I) tetrafluoroborate methanol 1.5-solvate

The title mononuclear chromium compound, [Cr(C32H28P2)( CO)(3)], (I), and its rhodium complexes [CrRh(C7H8)( C32H28P2)(CO)(3)]BF4 . 0.75CH(4)O, (II), and [CrRh(C8H12)( C32H28P2)(CO)(3)] BF4 . 1.5CH(4)O, (III), prepared as a ligand and precatalysts, respectively, for application in asymmetric homogeneous hydrogenation, have been studied by single-crystal X-ray diffraction. The structures of the free and complexed ligand are compared. It was found that the backbone of the ligand remains rigid on coordination, while only minor conformational changes of its side chains are observed. Both elements of central and planar chirality seem to build a well defined chiral environment for stereoselective catalysis.