A single-molecular pathway from heterometallic MM ' (M = Ba-II, Mn-II; M ' = Cr-III) oxalato complexes to intermetallic composite oxides

Thermolysis of {(n-C4H9)(4)N[(MnCrIII)-Cr-II(C2O4)(3)]}(n), 1 at 500 degrees C for 10 h gives spinel Mn1.5Cr1.5O4 which was characterized by powder XRD, SEM, FTIR and elemental analysis. The thermal conversion occurs by an internal redox process at ca. 400 degrees C in one step (TGA). It offers an alternative molecular source for an intermetallic oxide. Thermolysis of {[Ba-II (6)(H2O)(17)][Cr-III(C2O4)(3)](4)}center dot 7H(2)O, 2 under similar conditions gives a mixture of (BaCrO4)-Cr-II-O-VI and (BaCO3)-C-II. These results suggested that the oxalate ligand in a heterometallic complex may be a convenient source for oxides in intermetallic composites and that, under suitable conditions, both metals in the heterometallic complexes can be transferred to the intermetallic oxides. It suggested that composite metal oxides can be generated from hetero- and inter-metallic oxalato complexes at relatively low temperatures, which could serve as a convenient route for the preparation of technologically important composites.