Synthesis, Spectroscopic Characterization, DFT Calculations, and Dynamic Behavior of Mononuclear Macrocyclic Diorganotin(IV) Bis-Dithiocarbamate Complexes

Nine mononuclear diorganotin(IV) dithiocarbamate complexes 1–9 with 19-, 20- and 21-membered macrocyclic structures were synthesized from dimethyl, di-n-butyl, and diphenyltin(IV) dichloride and three bis-dithiocarbamate ligands derived from secondary bis-amines having aromatic spacer groups. All compounds were characterized by elemental analysis, mass spectrometry, and spectroscopic methods (IR and 1H, 13C, and 119Sn NMR). Additionally, quantum chemical DFT calculations were performed for the dimethyltin(IV) derivatives in order to model the molecular structures. For one compound series the NMR spectra showed a concentration-dependent behavior in solution, which was analyzed in detail and permitted to postulate the existence of an equilibrium with the corresponding [2+2] macrocycles.