IRIDAPYRROLE COMPLEXES VIA FORMAL 3+2 CYCLOADDITION OF IRIDIUM ALKENYLS TO ACETONITRILE

Under appropriate conditions, the bis(ethylene) derivative TpIr(C2H4) (2) (TP = hydrotris(3,5-dimethyl-1-pyrazolyl)borate) reacts with MeCN to provide the Ir(III) complex TpIr(CH=CH2)(C2H5)(NCMe) (1). In the presence of catalytic amounts of water, 1 undergoes intramolecular cou pling of the vinyl and acetonitrile ligands, with formation of a compo und (2a) that contains a delocalized, five-membered iridapyrrole ring. This unusual cycloaddition reaction can be extended to other related alkenyl complexes of iridium.