Carbon-13 nuclear magnetic resonance studies of isonitrile derivatives of tetracarbonylbis-(η-cyclopentadienyl)di-iron

Abstract

Variable temperature ¹³C n.m.r. studies on [(η-C₅H₅)₂Fe₂(CO)₃(CNR)](II; R = Bu^t) and (III; R = Ph) show that (II), which contains a terminally bonded CNR ligand, exhibits fluxional properties while (III), which contains a bridging CNR ligand, does not; it is also shown that ¹³C resonances of isonitrile ligands are diagnostic of the presence of bridging or terminal CNR groups.