Thermodynamic Studies of the Interaction of Nickel(II) Schiff Base Complexes with Diorganotin (IV) Dichlorides in Non‐Aqueous Solvents

A UV‐Vis spectrophotometric study of the adduct formation of the nickel(II) Schiff base complexes, ([NiL]) where L= [Salen, N,N′‐bis(salicylaldehydo)ethylenediimine], [Salpn, N,N′‐bis(salicylaldehydo)‐1,3‐propanediimine] and [Salophen, N,N′‐bis(salicylaldehydo)‐1,2‐phenylenediimine] as donors with R₂SnCl₂ (R=methyl and n‐butyl) as acceptors have been investigated in anisole, chloroform, N,N‐dimethylformamide (DMF) and methanol, as solvents. Adducts have been characterized by ¹H NMR, IR and electronic spectroscopy. The formation constants and the thermodynamic free energies were measured using UV‐Vis spectrophotometry titration for 1∶1 adduct formation at 25°C. The trend of the adduct formation of a given nickel Schiff base complex with a given tin acceptor in the solvents used decreases as follows: Methanol>DMF>Anisole>Chloroform. The formation constants of the nickel Schiff base complexes with a given tin acceptor in a given solvent decreases according to the following trend: Ni(Salpn)>Ni(Salen)> Ni(Salophen). The sequence of the reaction of R₂SnCl₂ acceptors toward a given nickel Schiff base complex in a given solvent is as follow: Me>n‐Bu.

Keywords:

• solvent effects
• nickel complexes
• Schiff base
• diorganotin dichloride
• formation constants
• adduct formation

We are grateful to Shiraz University Research Council for their financial support.