Synthesis, spectroscopic characterization, DFT calculations, and antimicrobial activities of N-arylsalicylaldiminate derivatives of diorganotin(IV)

Equimolar reaction of di-n-butyltin(IV) complexes of bidentate Schiff bases of the type [(n-Bu)₂Sn(sb)Cl] with sodium salt of mono-functional bidentate ligands in THF-benzene solution afforded structurally interesting complexes of the type [(n-Bu)₂Sn(sb)(L)] (1–6) [where sbH = Schiff bases: N-salicylidene-2-aminopyridine (sapH) I, N-salicylidene-2-methylaminobenzene (o-smabH) II, and N-salicylidene-4-methylaminobenzene (p-smabH) III; LH = mono-functional bidentate ligands, acetylacetone (acacH), ethanolamine (eaH)]. All these colored solid complexes were soluble in common organic solvents and characterized by elemental (C, H, N, and Sn) analysis, spectroscopic techniques [IR, (¹H, ¹³C, and ¹¹⁹Sn) NMR] and mass spectrometry. Thermogravimetric analysis of complexes shows thermal behavior and stability of complexes. Computational studies of the synthesized Schiff bases and their organotin(IV) complexes were carried out using DFT which validate the structure of complexes proposed on the basis of spectroscopic data. The mixed-ligand complexes of diorganotin(IV) and Schiff bases were screened for their antibacterial and antifungal activities.