Synthesis,electrochemical behavior and X-ray crystal and molecular structures of [Fe(diene)(CO)2PPh3] (diene=chalcone,sorbic acid)

The compounds Fe(ch)(CO)₂PPh₃] (1) (ch=chalcone) and Fe(sba)(CO)₂PPh₃] (2) (sba=sorbic acid) were prepared by irradiating the tetracarbonyltriphenylphosphineiron(0) complex in benzene in the presence of ch or sba. The compounds were characterized by infrared and ³¹P NMR spectroscopies. Their electrochemical behavior was investigated by cyclic voltammetry and the results suggest that their oxidations occur by more than one electrochemical step, producing free ch and sba, free PPh₃ and solvated Fe(III). It was observed that sba ligand contributes more effectively to the stabilization of metal center in these complexes. The X-ray crystal and molecular structures of 1 and 2 were determined; it was shown that the Fe atom adopts a distorted octahedral coordinated geometry in which three of the sites are occupied by the ch or sba ligand. The Fe(ch)(CO)₂PPh₃] complex is a monomer and the unit cell of complex 2 contains exist two identical and crystallographically independent molecules of Fe(sba)(CO)₂PPh₃] which are linked by short hydrogen bonds OH· · ·O