Electronic effects of substituents on the stability of the iridanaphthalene compound [IrCp*{C(OMe)CHC(o-C6H4)(Ph)}(PMe3)]PF6

Abstract

Iridanaphthalene complexes are synthesized from the corresponding methoxy(alkenyl)carbeneiridium compounds. The electronic character of the substituents on the 6-position of the metallanaphthalene ring is crucial from the point of view of the stability of the iridanaphthalene, [IrCp*{C(OMe)CHC(o-C₆H₄)(Ph)}(PMe₃)]PF₆, vs. its transformation to the corresponding indanone derivatives. Stability studies of the iridanaphthalene compounds revealed that strong electron donor substituents (–OMe) stabilize the iridanaphthalene, while weak electron donor (–Me) and electron withdrawing (–NO₂) groups favor the formation of indanone derivatives. Two possible indanone isomers can be obtained in the conversion of the unstable iridanaphthalene complexes and a mechanism for the formation of these isomers is proposed.