TRIPOD RHODIUM COD COMPLEXES - SYNTHESIS, STRUCTURE, DYNAMICS AND CATALYSIS

The reaction of the tripod Ligands R'C(CH(2)PR(2))(3) (1a-c) and X(2)P OCH[CH2P(Ph)(2)](2) (2a-c) with [Rh-I(COD)Cl](2)] is investigated. It yields tripod rhodium COD complexes [(1a-c)Rh-I(COD)]Y (3a-c) and [(2a -c)Rh-I(COD)]Y [4a-c; Y = B(Ph)(4), PF6]. The tripod ligand is coordin ated by all three donor groups in each case, irrespective of the diffe rent donor capabilities of the coordinating groups. The solid state st ructure of compounds 3a-c and 4a is determined by X-ray analysis. The observed coordination polyhedra delineate the variation from the ideal ized trigonal bipyramide to an idealized quadratic pyramide. In soluti on the analysis of the NMR spectra shows a rapid intramolecular interc onversion according to a turnstile pseudo rotation. The complexes 3a a nd 4a are found to be catalysts for the hydrogenation of prochiral ole fines.