SYNTHESIS, MECHANISM OF FORMATION AND CHARACTERIZATION OF A NEW CLASSOF OCTANUCLEAR MIXED-METAL CLUSTERS NA2M'2[M3O4(O2CET)8]2 (M'=CR OR V, M=MO OR W)

The reaction of Na[M3O2(O2CEt)9] with Cr(CO)6 or M(CO)6 and CrCl3.6H2O in propionic anhydride solution at 120-degrees-C has resulted in the formation of the insoluble octametallic clusters Na2Cr2[M3O4-(O2CEt)8] 2 (M = Mo 1 or W 2). The skeletal conversion of [M3O2(O2CEt)9]- into [ M3O4(O2CEt)8]4- and the mode of formation of compounds 1 and 2 from th e latter species and Cr3+ and Na+ ions has been established. The vanad ium analogues (M = Mo 3 or W 4) have been synthesized by the reactions of M(CO)6(M = Mo or W) with NaVO3.2H2O under similar reaction conditi ons. Clusters 1-4 have been characterized by X-ray crystallography, IR spectra and magnetic susceptibility measurements.