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

The compounds [Fe(ch)(CO)(2)PP3] (1) (ch = chalcone) and [Fe(sba)(CO)(2)PPh 3] (2) (sba = sorbic acid) were prepared by irradiating the tetracarbonyltr iphenylphosphineiron(0) complex in benzene in the presence of ch or sba. Th e compounds were characterized by infrared and P-31 NMR spectroscopies. The ir electrochemical behavior was investigated by cyclic voltammetry and the results suggest that their oxidations occur by more than one electrochemica l step, producing free ch and sba, free PPh3 and solvated Fe(III). It was o bserved that sba ligand contributes more effectively to the stabilization o f metal center in these complexes, The X-ray crystal and molecular structur es of 1 and 2 were determined; it was shown that the Fe atom adopts a disto rted octahedral coordinated geometry in which three of the sites are occupi ed by the ch or sba ligand. The [Fe(ch)(CO)(2)PPh3] complex is a monomer an d the unit cell of complex 2 contains exist two identical and crystallograp hically independent molecules of [Fe(sba)(CO)(2)PPh3] which are linked by s hort hydrogen bonds O-H . . .O (C) 2001 Published by Elsevier Science Ltd.