Synthesis, characterization and equilibrium study of the dinuclear adducts formation between nickel(II) Salen-type complexes with diorganotin(IV) dichlorides in chloroform

Adduct formation between R2SnCl2 (R = methyl and n-butyl) as acceptors, and nickel(II) complexes of tetradentate Schiff base ligands ([NiL]) where L = [3-methoxysalen, N,N'-bis(3-methoxysalicylidene)ethylenediamine], [4-methoxysalen, N,N'-bis(4-methoxysalicylidene)ethylenediamine], [5-methoxysalen, N,N'-bis(5-methoxysalicylidene)ethylenediamine], [salen, N,N'-bis(salicylaldehydo)ethylenediamine], [5-chlorosalen, N,N'-bis(5-chlorosalicylidene)ethylenediamine] and [5-bromosalen, N,N'-bis(5-bromosalicylidene) ethylenediamine] as donors have been investigated in chloroform as a solvent by means of UV-Vis spectrophotometeric analysis. Adducts have been characterized. by H-1 NMR, IR and electronic spectroscopy. The formation constants and the thermodynamic free energies were measured using UV-Vis spectrophotometry titration for]:I adduct formation at various temperatures (T = 278308 K). The trend of the adduct formation of the nickel Schiff base complexes with a given tin acceptor decreases as follow: Ni(3-MeOSalen) > Ni(5-MeOSalen) > Ni(4-MeOSalen) and Ni(5-MeOSalen) > Ni(Salen) > Ni(5-BrSalen) >= Ni(5 - ClSalen) The trend of the reaction of R(2)SnCl(2)acceptors toward a given nickel Schiff base complex is as follow: Me > n-Bu (c) 2006 Elsevier B.V. All rights reserved.