Photochemical Reactions of M(CO) 5 THF (M = Cr, Mo, W) with Salen Type (-ONNO-) Schiff Bases

The hitherto unknown complexes, cis-[M(CO) 2 (η 4 -H 2 L′)], [M = Cr; 1, Mo; 2, W; 3] and cis-[M(CO) 2 (η 4 -H 2 L”)], [M = Cr; 4, Mo; 5, W; 6] have been synthesized by the photochemical reactions of photogenerated intermediate, M(CO) 5 THF (M = Cr, Mo, W) with salen type Schiff base ligands, N,N′-bis(salicylidene)-1,4-diaminobutane (H 2 L′) and N,N′-bis(2-hydroxy-3-methoxybenzylidene)ethylenediamine (H 2 L”). The complexes have been characterized by elemental analyses, LC- mass spectrometry, magnetic studies, FTIR and 1 H NMR spectroscopy. The spectroscopic studies show that H 2 L′ and H 2 L” ligands coordinated to the central metal as tetradentate ligands coordinating via the central azomethine nitrogens (C = N) and phenolic oxygen atoms in complexes 1-3 and via aromatic methoxy and phenolic oxygen atoms in complexes 4-6, respectively.