FORMATION OF THE NOVEL P6 CHAIN LIGAND FROM 2 P3 RINGS BOUND TO METAL-LIGAND SYSTEMS

The reactions of the isoelectronic [(triphos)Ni(P3)]BF4 and [(triphos) Co(P3H)] CF3SO3 complexes, containing the eta3 coordinated P3 unit, wi th the carbene like Pt(PPh3)2 fragment have been investigated. The nic kel derivative yields the [(triphos)Ni(P3)Pt(PPh3)2] BPh4 compound whi ch is formed through the insertion of the platinum fragment into a P-P bond of the inorganic P3 ring. The compound exhibits a dynamic behavi our in solution which can be rationalized, as suggested by the P-31 NM R spectra at low temperatures, in terms of a whizzing motion of the pl atinum fragment over the P3 unit. The cobalt derivative yields a compo und of formula [{(triphos)Co}2(P6H2)PtPPh3](CF3SO3?? )2 in which a P6 fragment, attained through the formation of a P-P bond between phospho rus atoms of two P3 groups, is stabilized by coordination to three met al-ligand fragments. Both the nickel and the cobalt compounds have bee n characterized by complete X-ray analyses.