Synthesis and charaterisation of cobalt complexes of salicylaldehyde 4-methoxybenzoyl hydrazone (H-2 smbhon)

A number of mononuclear and dinuclear cobalt(II) and cobalt(III) complexes have been isolated by reacting salicylaldehyde 4-methoxybenzoyl hydrazone ( H(2)smbhon) with CoCl2.6H(2)O, Co(NO3)(2)6H(2)O, Co(CH3COO)(2).4H(2)O and C o(acac)(3) under varied reaction conditions. [Co-II(smbhon)(H2O)(3)], isola ted in this study, further reacts with pyridine (Py) dipyridine (dip) and t riphenylphosphine (Ph3P) in presence of NaClO4 to form new cobalt (III) com plexes. Equimolar mixtures of [Co-II (smbhon)(H2O)(3)] and the ligands like acetylacetone (Hacac), glycine (Hgly), N,N-bisethyleneacteophenoneimine (b ape),N-phenylsalicylaldimine (Haslan), N-phenylortho-hydroxyacetophenoneimi ne mine (Hohapan), N-hydroxymethylsalicylaldimine (H(2)salgly), N-2-hydroxy phenylsalicylaldimine (H(2)saloap) or N-2-carboxyphenylsalicylaldimine (H(2 )salana) on refluxing in methanol-acetonitrile in the presence of oxygen at pH - 9 afford coloured heterochelates of cobalt (III) in high yields. Stru ctures of the complexes have been assigned on the basis of elemental analys es, molecular weights, molar conductances, magnetic moments and spectral (U V-vis and IR) studies. The physico-chemical data suggest that H(2)smbhon ca n behave as a dibasic tridentate (ONO) donor, monobasic tridentate (ONO) (k eto form) donor and monobasic bidentate (NO) donor depending on the reactio n conditions.