Oxido and imido complexes of type ReVOCl3(dppz) and ReV(NPh)Cl3(dppz) having meridional geometry (where dppz is 3,6-di(2-pyridyl)pyridazine) have been isolated and characterized. The oxygen atom transfer from ReVOCl3(dppz) to PPh3 has afforded ReIII(OPPh3)Cl3(dppz) which on chemical oxidation by HNO3 yielded [ReIV(OPPh3)Cl3(dppz)]ReO4. Treatment of ReIII(OPPh3)Cl3(dppz) with PPh3 has furnished facial ReIII(PPh3)Cl3(dppz). The second-order rate law and large negative entropy of activation (-15.8 eu) of the oxygen atom transfer reaction of ReVOcl3(dppz) with PPh3 is consistent with an associative pathway initiating through nucleophilic phosphine attack to Re≡O π * orbitals.
Oxidorhenium(V), Imidorhenium(V), Pyridylpyridazine, Oxygen atom transfer