Three new Ag(I) thiosaccharinate complexes: Synthesis, structural studies, spectral characterization and theoretical analysis

Abstract

Three silver thiosaccharinate complexes, two of them with diverse coordination geometries controlled by the ancillary nitrogen donor ligands are presented. The dinuclear silver thiosaccharinate complex, catena-poly-[Ag2(tsac)2]·C3H7NO (1·DMF), (thiosaccharinate = thiosaccharinate anion, DMF = dimethylformamide) in the crystalline state is a one dimensional coordination polymer bridged by the thiosaccharinate ligand with a very short silver-silver distance, 2.8930(16) Å. The biquinoline silver(I) thiosaccharinate, [Ag(tsac)(2,2′-bquin)]·CH3CN (2·CH3CN), (bquin = 2,2′-biquinoline) in the crystalline state consists of a mononuclear neutral unit solvated with an acetonitrile molecule. The double complex salt, [Ag(2,4,6-coll)2][Ag(tsac)2] (3), (2,4,6-coll = 2,4,6-collidine) possesses a very unusual arrangement for a silver thiosaccharinate, one similar to an ionic silver-pyridine based structure. The complex cation is formed by two 2,4,6-trimethylpyridine molecules coordinated to the silver atom while the complex anion is composed of two thiosaccharinate anions coordinated to the silver atom. In both cation and anion, the silver center has a linear geometry with the ligands planar. The syntheses, full characterizations and crystal structures of the three complexes are described. The structures of these newly synthesized silver(I) thiosaccharinate complexes have been optimized and their structural parameters have been calculated at the B3LYP/6-31G(2d,p)/LANL2DZ level of theory. The 13C NMR chemical shifts for the DMSO solution species of (2) and (3) were calculated using DFT/EPR-III/DZP first principles calculations with B3LYP, OLYP, OPBE, HCTH93 functionals.