Nature of the Bridging Nitrido Ligand, Synthesis and Reactivity ofHeterobimetallic Nitrido-Bridged Compounds

摘要

Heterobimetallic nitrido-bridged compounds (R3SiO)3V(triple bonds)N-M(CO)(PPh3)2(R = Me or Et and M = Ir or Rh) and (Me3SiO)3V(triple bonds)N-Rh(PPh3)3 have been synthesized by condensation reactions between vanadium silylimido compounds. V(NSiR3)(OSiR3)3, and group VIII metal fluorides, MF(L)(PPh3)2. Oxidative addition of small molecules (Mel, 02, H2) to the iridium(I) of (R3SiO)3V(triple bonds)N-Ir(CO)(PPh3)2 occurs, producing iridium(III) compounds in which the V-N-Ir interaction is retained. In contrast, however, the nitrido linkages in (Me3SiO)3V(triple bonds)N-M(L)(PPh3)2 are readily cleaved by silylating reagents (ClSiMe3, ClSiEt3, HSiEt3), producing V(NSiR3)(OSiMe3)3 and a group VIII metal chloride or hydride product. Comparison of the reactivity and spectroscopic data among the nitrido-bridged compounds and with related iridium(I) and rhodium(I) complexes suggests that the nitrido-bridged compounds are best viewed as adducts in which anionic (R3SiO)3V(triple bonds)N: acts as a simple two-electron donor to the 14-electron cationic M(L)(PPh)2+ fragment. jg.