Unusual coordination in a silver thionate complex. Synthesis, structural characterization and theoretical calculations of dinuclear and polynuclear silver(I) thiosaccharinates with pyridine and 1,10-phenanthroline

Treatment of Ag6(tsac)6 (tsac = thiosaccharinate anion) with pyridine (py) and 1,10-phenanthroline (o-phen) each affords two novel silver(I)-thiosaccharinate complexes: dinuclear [Ag2(tsac)2py] (1) and polynuclear [Ag(tsac)(o-phen)]n (2). Both crystal structures have been determined by X-ray diffraction and spectroscopic structural analysis (IR and Raman, UV–Vis, 1H and 13C NMR) have also been made for both compounds. Thermal stability analysis (TGA and DTA) of complex 1 are used to confirm the strength of the pyridine coordination to the silver ion. The molecular structure of complex 1 shows some astonishing characteristics. The two silver atoms are in different environments: one of them is surrounded by two S atoms, while the other completes its coordination sphere by three N atoms, two from the thiosaccharinate anions and the third from a pyridine molecule. The short Ag(1)–Ag(2) contact distance, 2.9681(8) Å, indicates an interaction between the two silver metal atoms exists. Complex 2 shows a thiosaccharinate molecule bridging two silver atoms through the exocyclic S atom while the o-phenanthroline ligand is coordinated as a bidentate N,N chelate, forming a polynuclear chain. Quantum chemical calculations confirm the argentophilic character of the Ag–Ag interaction in complex 1, and its structure and vibrational assignments were correlated and confirmed theoretically.

Graphical abstractNew ternary silver(I) thiosaccharinates with pyridine and 1,10-phenanthroline are prepared and structurally characterized. The pyridine derivative is a dinuclear silver complex, [Ag2(tsac)2py], with argentophilic interaction and very unusual metal environments. One Ag(I) is coordinated by two S atoms and the other silver atom by three N atoms.Figure optionsDownload full-size imageDownload as PowerPoint slide