SYNTHESIS AND CHARACTERIZATION OF MOLYBDENUM(VI) OXO-SPECIES ON THE SURFACE OF FUMED ALUMINA AND SILICA

Synthesis of molybdenum(VI) ore-species on the surface of alumina and silica supports was carried out by their chemical modification with a dichloromethane solution of MoOCl4 followed by hydrolysis of the ancho red groups ((sic)-O)(n)MoOCl4-n and subsequent thermal treatment. In t he case of alumina, the formation of monomeric molybdenum(VI) ore-spec ies which strongly interact with the support surface is observed. Mo6 ions in these species are found to be tetrahedrally coordinated. On t he silica surface, at least two types of molybdenum(VI) ore-species ar e detected. Aggregated molybdenum(VI) ore-species in which Mo6+ ions h ave an octahedral coordination appear to be predominant. (C) 1997 Else vier Science B.V.