Synthesis, spectral characterization and DFT calculations of novel Ag(I) π-coordination polymeric complexes based on N-allylmorpholine-4-carbothioamide

Abstract

Two complexes of Ag(I) with the N-allylmorpholine-4-carbothioamide (HL) with general formula ([Ag(HL)NO3]·3H2O)n (1) and [Ag(HL)NO3]n (2) were synthesized and isolated in crystalline state. X-ray diffraction study of compounds showed that both complexes are coordination polymers which differ by coordination manners of nitrate anions and presence of cocrystallized water molecules. In solid state in both complexes the ligand molecules are coordinated in bridging mode by μ2-S atom and the CC double bond of the allyl moiety with formation of stable six-membered chelate metallocycles and 1D Ag–S–Ag polymeric chains. However dissolution of the complexes in DMSO leads to cleavage of polymeric chains as well as Ag-(CC) π-coordination bonds, as evidenced by the 1H and 13C NMR spectroscopy data. Crystallographic data have also revealed so-called “additional” coordination of Ag+ ions, which complements the “usual” coordination polyhedra of Ag+ expanding its coordination numbers from 3 to 5 and 6, leading to stabilization of such compounds in solid state. Results of DFT calculation of IR spectra were compared with experimental data and fragmentation of complexes was investigated by MALDI-TOF mass spectrometry and TPD MS methods.