Novel complexes of silver(i) sulfate with 1-methylimidazole-2-thione: Structures and vibrational spectroscopy

摘要

Crystallization of silver(i) sulfate with the ligand 1-methylimidazole-2- thione ('Hmimt') from aqueous solution, instead of yielding the expected 1:6 Ag_2SO_4:Hmimt complex analogous to numerous other Ag _2SO_4:thiourea-based ligand (1:6) complexes, has resulted in novel polymeric forms, one of unusual stoichiometry. Ag_2SO _4:Hmimt (1:4) (·H_2O) is of the form [?(μ-Hmimt)_2Ag(μ-Hmimt)_2Ag?] (∞|∞)(SO_4), with a one-dimensional polymeric cation. Ag_2SO_4:Hmimt (3:8) (·9H_2O) is a polymeric sheet structure containing Ag_(12)(SO_4) _6(Hmimt)_(15) kernels linked by Hmimt ligands. The IR spectra of these compounds show unusually large shifts of the ν(NH) band due to the presence of N-H?O hydrogen bonding involving the N-H group of the ligand and the sulfate oxygen atoms. The complexes were also readily prepared by the solvent-assisted mechanochemical method, and the utility of this method for the preparation of deuterium-exchanged products for assistance in the assignment of the IR spectra is illustrated.