Synthesis and structural characterization of dimethyltin(IV) complexes based on functionalized pyridyl ligands

Four coordinate tin complexes: synthesis, characterization, thermodynamic and theoretical calculations

In this work, two new Sn(IV) complexes, [SnL(x)]Cl2 where (L(x))(2-) is the deprotonated form of 5-A-salabza-H2=N,N'-bis(salicylidene)-2-aminobenzylamine and A=5-OMe, 5-H, 5-NO2, 5-Br, were synthesized and fully characterized by UV-Vis, FT-IR, (1)H NMR, (13)C NMR, (119)Sn NMR spectroscopies, mass spectrometry and elemental analysis. The thermodynamic formation constants of the complexes were determined spectrophotometrically at 25 °C in acetonitrile. The trend of formation constants of the complexes are as: 5-OMe>5-H>5-NO2>5-Br and Ph2SnCl2>Me2SnCl2>n-Bu2SnCl2. DFT/B3LYP molecular orbital calculations were carried out for the 5-H substituent isomer, [SnL(2)](2+), in an attempt to explain the structure of complexes. The optimized resulting geometries, vibrational frequencies and the NMR resonances of the complexes are discussed.