Reactions of Group 6 Metal Carbonyls with Salicylaldehyde Hydrazone

The interaction of salicylaldehyde hydrazone (shH) with Cr(CO)6 in the absence of oxygen resulted in the formation of the tris derivative Cr(sh)3, 1. Reactions of M(CO)6, M = Cr, Mo in air gave the oxo derivatives M(O)(sh)2, 2 and 3, with the metal atom in +4 formal oxidation state. Prolonged heating of a mixture of Mo(CO)6 and shH in air resulted in the formation of the dinuclear complex Mo2(O)6(shH), 4. Structures for the complexes were proposed based on the spectroscopic studies. Reactions of W(CO)6 with shH in air or under reduced pressure lead to the formation of the salicylaldehyde azine dimer via elimination of a hydrazine molecule. The structure of the dimer was confirmed by crystal structure determination and by FTIR and FT‐Raman spectroscopy.