Iridium and platinum complexes of diethyl azodicarboxylate and 4-phenyl-1,2,4-triazoline-3,5-dione

Abstract

Chlorocarbonylbis(triphenylphosphine)iridium reacts in benzene with diethyl azodicarboxylate and 4-phenyl-1,2,4-triazoline-3,5-dione to form the complexes (Ph₃P)₂Ir(NCO₂Et)₂(CO)Cl and (Ph₃P)₂Ir[(NCO)₂NPh](CO)Cl, respectively. Chlorocarbonylbis(methyldiphenylphosphine)iridium forms an analogous complex with diethyl azodicarboxylate. I.r. and ¹H n.m.r. studies suggest that the complexes have the phosphine ligands in a relative trans-configuration. Related reactions with tetrakis(triphenylphosphine)platinum gave the compounds (Ph₃P)₂Pt(NCO₂Et)₂ and (Ph₃P)₂Pt[(NCO)₂NPh]. An attempt to extend the reactions of diethyl azodicarboxylate to tetrakis(methyldiphenylphosphine)platinum and tetrakis(triphenylphosphine)palladium afforded only 1,2-bis-(ethoxycarbonyl)hydrazine. Diethyl azodicarboxylate adds to nickelocene to form a red complex, formulated as arising by addition of the azo-compound to one of the π-cyclopentadienyl rings.