Reactions of Chromium and Molybdenum Carbonyls With a Quadridentate Schiff Base

Interaction of a Schiff base derived from 2-hydroxyacetophenone and ethylenediamine (hapenH2) with M(CO)6, M = Cr and Mo, in THF under atmospheric pressure gave the oxo derivatives M(O) (hapen) with the metal atom in +4 formal oxidation state. IR spectra of the complexes revealed the presence of the M = O bond. The dihydride complex MoH2(CO) (hapen) was also isolated from the reaction of Mo(CO)6 and happen H2 under reduced pressure; v(CO) and v(Mo-H) frequencies were clearly indicated in its IR spectrum. The three complexes were found to be paramagnetic. Magnetic susceptibility measurements suggested that the d 4 Mo atom in MoH2 (CO) (hapen) exists in a low spin configuration. Electronic spectra of the ligand and its complexes in different donor solvents displayed bands due to compound-solvent, charge-transfer complexes.