REACTIONS OF DIOXO[N-(SALICYLIDENE)-2-AMINOPHENOLATO-N,O,O'](HEXAMETHYLPHOSPHORAMIDE)MOLYBDENUM(VI) COMPLEXES WITH SUBSTITUTED HYDRAZINES AND CHEMISTRY OF MOLYBDENUM(VI)-HYDRAZIDO COMPLEXES

The reaction of dioxo[N-(salicylidene)-2-aminophenolato-N,O,O'] (hexamethylphosphoramide)molybdenum(VI), 4a, and its C-imine substituted derivatives, 4b,c with different mono- and di-substituted hydrazines has been investigated. The reaction of 4a with 1,1-dimethylhydrazine leads to decomposition of the complex. When complex 4b is treated with 1,1-dimethylhydrazine an eta(1)-coordinated hydrazido(2-) molybdenum complex, 8a, is formed. The 2-aminophenolato-N,O ligand present in 8a originates from cleavage of the salicylidene ligand in 4b. The structure of 8a is determined by an X-ray crystallographic investigation. The electronic structure of 4b and 8a is investigated using extended Huckel calculations and based on the results for 4a, a mechanism for the formation of 8a is postulated. The chemical properties of 8a are discussed on the basis of its electronic structure. A general method for the preparation of a series of complexes similar to 8a has been developed. A minor product is also formed in the reaction of methylhydrazine with 4b and the possible structures of this complex are discussed; it is postulated that the hydrazido ligand in this complex might coordinate to the molybdenum atom in an eta(2)-fashion. The chemical properties of the eta(1)-coordinated hydrazido(2-) molybdenum complex, 8a, have been investigated and reactions with e.g. hydrogen chloride, dimethyl sulfate, benzaldehyde and benzoyl chloride have been performed.