SYNTHESIS AND CRYSTAL-STRUCTURES OF THE DISTORTED PENTAGONAL BIPYRAMIDAL 7-COORDINATE ACETYLACETONATE COMPLEXES [MI(ACAC)(CO)(2)(PET3)(2)] (M=MO OR W)

Equimolar quantities of [MI2(CO)(3)(PEt3)(2)] (M = Mo or W) and Na[aca c] react in a Et2O/CH2Cl2/EtOH mixture at room temperature to give hig h yields of the seven-coordinate complexes [MI(acac)(CO)(2)(PEt3)(2)] (1 and 2). The crystal structures of 1 and 2, while not isomorphous, s how similar seven-coordination geometries with the acetylacetonate lig and coordinating in a bidentate manner. The geometry around these comp lexes can best be described as distorted pentagonal bipyramidal with o ne carbonyl and iodine in the axial positions and the acetylacetonate ligand, two phosphine ligands and one carbonyl group in equatorial pos itions. Spectroscopic data for 1 and 2 are reported. (C) 1997 Elsevier Science S.A.