Mononuclear Diphenyltin(IV) Complexes with Salicylaldimine Schiff Bases: Synthesis, Structures, and Electrochemical Properties

New mononuclear tin(IV) complexes are synthesized by the condensation of diphenyltin oxide Ph₂SnO with a number of Schiff bases containing the hydrazone fragment. The structures of the complexes are confirmed by ¹H, ¹³C, and ¹¹⁹Sn NMR spectroscopy and X-ray diffraction (XRD) (CIF files CCDC nos. 2443096 (IV) and 2443095 (V)). The electronic and redox properties of complexes I–V are studied using UV spectroscopy and cyclic voltammetry, and the energy bandgap is estimated. The electrochemical oxidation and reduction of complexes I, II, IV, and V are irreversible and accompanied by further chemical transformations. Unlike them, the electroreduction of complex III with the pincer ligand leads to the formation of stable radical anion species.