ISOCYANIDE-BRIDGED AND HETEROALLENE-BRIDGED METAL-COMPLEXES .8. DIIRON COMPLEXES WITH BRIDGING ACYL ISOCYANIDE AND IMINOACYL ISOCYANIDE LIGANDS

Acylation (aroylation, carbamoylation, imino acylation) of the terminal cyano ligand in Na[Fe2(CN)CP2(CO)3] (1) leads to the acyl isocyanide (aroyl, carbamoyl, iminoacyl isocyanide)bridged neutral complexes [Fe2CP2{mu-CNC(=O)R}(CO)3] (2a-i) and [Fe2CP2(mu-CNC(=NPh)Ph}(CO)3] (3). An X-ray structure analysis has been carried out of the pentafluorobenzoyl isocyanide complex 2f, important results of which are the cis configuration of the complex, the 163.7-degrees puckering of the central Fe2(mu-C)2 rhomboid, short [1.892(5), 1.911(5) angstrom] Fe-mu-C distances to the acyl isocyanide ligand, the nonplanarity of the latter and the 132-degrees bend at the isocyano nitrogen. The contribution Of a mu-2-2-azaallenylidene form is assumed to explain the bonding.