Homo- and hetero-binuclear complexes of a compartmental Schiff base ligand. Synthesis and characterisation

Abstract

Reaction of 3-formylsalicylic acid with diethylenetriamine yields the Schiff base {N,Nʹ- 2,2ʹ-bis(aminoethyl)methylaminebis(3-carboxysalicylidimine)}(H₄fsadien). The interaction of H₄fsadien with CoCl₂·6H₂O produces [(H₂fsadien)Co^II] and silylation and lithiation of which, having two free - COOH groups with Me₃SiCl or trimethylsilyl N,N'-diphenylurea (TDPU) and LiOH, yields disilylated and dilithiated products, [{ (Me₃Si)₂(fsadien)}Co^II] and [{ (Li)₂(fsadien)}Co^II], in good yield. This disilylated or dilithiated product smoothly reacts with (π-C₅H₅)₂ TiCl₂, (π-C₅H₅)₂ ZrCl₂, Me₂SnCl₂, Ph₂SnCl₂ and MX₂.nH₂O (where M=Ni²⁺, Cu²⁺, Co²⁺, Pd²⁺, VO²⁺ and X=Cl^ˉor CH3COOˉ) affording some new homo- and heterobinuclear complexes, including some organo-derivatives. The reactions of H₄fsadien with FeCl₃.6H₂O and Co(NO₃)₂.6H₂O in access of oxygen also yield di-iron(III) and di-cobalt (III) complexes. The complexes are characterised by elemental analyses, molecular weights, magnetic moment values, molar conductance values and spectroscopic data (IR and electronic) data. In all these complexes, the Schiff base, H₄fsadien, functions as tetrabasic bridging hexadentate/heptadentate ligand using inner compartment of N₂O₂ or N₃O₂ donor set and outer compartment of O₂O₂ donor set.