Reactions of chromium and molybdenum carbonyls with bis-(salicylaldehyde)-1,3-propylenediimine Schiff base

Abstract

Interaction of a Schiff base, bis-(salicylaldehyde)-1,3-propylenediimine, salpenH₂, with M(CO)₆ (M = Cr or Mo) in the presence of oxygen gave the oxo-complexes[M(O)(salpen)]. Magnetic studies for the two oxo-complexes showed chromium and molybdenum in the +4 formal oxidation state. In presence of pyridine, reaction of Cr(CO)₆ with salpenH₂ gave the identical product; [Cr(O)(salpen)]. Reaction of Mo(CO)₆ with salpenH₂ in presence of pyridine (py) resulted in formation of the square-pyramidal complex [Mo(py)(salpenH₂)]. Reactions of M(CO)₆ with salpenH₂ in presence of a ligand L (L = bipyridine (bpy) or 3,3-dimethylbipyridine (dmbpy)) gave the octahedral complexes [M(L)(salpenH₂)]. All the complexes were characterized by elemental analyses, IR, mass and ¹H NMR spectroscopy. The spectroscopic studies revealed the proposed structures. UV-Vis spectra of the ligand and its complexes in DMSO exhibited visible bands due to metal-to-ligand or ligand-to-metal charge transfer.

Keywords:

• Bis-(salicylaldehyde)-1,3-propylenediimine
• Complexes
• Metal carbonyls
• Spectra
• Pyridine derivatives
• Charge transfer