SOL-GEL APPROACH TO SYNTHESIS OF MO2O3 - MOO(OH) AND OTHER INTERMEDIATES FROM HYDROLYSIS OF MOLYBDENUM(III) ALKOXIDES AND MO2(NME2)6

The products of hydrolysis of Mo2(NMe2)6, Mo4(OEt)12, Mo2(O-i-Pr)6, and Mo2(O-t-Bu)6 in hydrocarbon solvents have been studied. The latter two result in extensive oxidation of the molybdenum and cannot be used for preparation of Mo(III) compounds. Hydrolysis of Mo2(NMe2)6 provides a black crystalline precipitate that yields an amorphous red-brown material, Mo3(OH)9(NMe2).1/2HNMe2, upon filtration and drying. A brown compound of Mo(III), Mo2(OH)5(OEt), is obtained upon hydrolysis of Mo4(OEt)12. Thermolysis of Mo3(OH)9(NMe2).1/2HNMe2 ultimately yields a material that retains nitrogen tenaciously. Thermolysis of Mo2(OH)5(OEt) in vacuo at 240-degrees-C leads to evolution of ethene and ethane as major gaseous products and oxidation of the molybdenum from an average oxidation state 3.0 to 3.4. Upon reaction of Mo2(OH)5(OEt) with H2 at 250-degrees-C, the new compound MoO(OH) is produced. Conversion of the latter to Mo2O3 was not successful, giving the material Mo3O5 instead. The reactive MoO(OH) converted cleanly to the crystalline layered compound LiMoO2 upon reaction with Li2CO3 at 600-degrees-C in vacuo. Magnetic susceptibilities and Mo 3d XPS data are reported for Mo2(OH)5(OEt) and MoO(OH).