Synthesis, mechanism of formation and characterization of a new class of octanuclear mixed-metal clusters Na2M′2[M3O4(O2CEt)8]2(M′= Cr or V; M = Mo or W)

Abstract

The reaction of Na[M₃O₂(O₂CEt)₉] with Cr(CO)₆ or M(CO)₆ and CrCl₃·6H₂O in propionic anhydride solution at 120 °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 the latter species and Cr³⁺ and Na⁺ ions has been established. The vanadium 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 conditions. Clusters 1–4 have been characterized by X-ray crystallography, IR spectra and magnetic susceptibility measurements.