Synthesis, crystal structures, spectroscopic and thermal properties of silver(I) saccharinate complexes with N-donor ligands

The synthesis, spectroscopic and thermal properties and X-ray structures of four silver(I) saccharinate complexes with N-donor ligands, [Ag(sac)(edmen)] (1), [Ag(sac)(teten)] (2), [Ag2(sac)2(o-bix)2] (3) and [Ag(sac)(dpa)] (4) (edmen = N-ethyl-N′,N′-dimethylethylenediamine, teten = N,N,N′,N′-tetrakis(2-hydroxyethyl)ethylenediamine, o-bix = 1,2-bis(imidazole-1-ylmethyl)benzene and dpa = 2,2′-dipyridylamine) are described. In complex 1, the Ag(I) ion is coordinated by two N atoms from edmen and one N atom from sac ligand, forming a slightly distorted Y-shaped AgN3 arrangement. In complex 2, the Ag(I) is four coordinated by N-bonded sac and tridentate teten ligands, exhibiting a seesaw AgN3O geometry. A crystallographically independent Ag(I) ion in 3 is surrounded with a T-shaped geometry by two N atoms from o-bix ligand and one N atom from one sac ligand, and the Ag⋯Ag separation is 3.338 Å. In complex 4, the Ag1 ion is coordinated by three nitrogen atoms from sac and dpa ligands to form a distorted Y-shaped geometry. The dpa ligand behaves as a bidentate ligand, forming a six-membered chelate ring, while the sac ligand is N-coordinated. The most striking feature of complexes 1 and 2 is the presence of both intra- and intermolecular C–H⋯Ag hydrogen-bonding interactions. Crystal packing of complexes is achieved by the hydrogen bonds, intra- and/or intermolecular C–H⋯π, weak π⋯π and Ag⋯π interactions to generate a three-dimensional supramolecular network. The photoluminescence spectrum shows that 4 displays a red-shift emission in the solid state at room temperature.

Graphical abstractWe synthesized and characterized four Ag(I) saccharinate complexes with N-donor ligands, [Ag(sac)(edmen)] (1), [Ag(sac)(teten)] (2) [Ag2(sac)2(o-bix)2] (3) and [Ag(sac)(dpa)] (4). The most striking features of complexes 1 and 2 are the presence of both intra- and intermolecular C–H⋯Ag hydrogen-bonding interactions. Crystals packing of complexes are achieved by the hydrogen bonds, intra- and/or intermolecular C–H⋯π, weak π⋯π and Ag⋯π interactions to generate a three-dimensional supramolecular network. Spectral and thermal analysis data for complexes are in agreement with the crystal structures. The photoluminescence spectrum shows that complex 4 displays red-shift fluorescent emission in the solid state at room temperature.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Synthesis and crystal structures of four mixed ligand silver(I)-saccharinate complexes with N-donor ligands. ► Intra- and inter-molecular C–H⋯Ag hydrogen-bonding interactions. ► Ag⋯π, C–H⋯π and π⋯π interactions. ► Red-shift fluorescent emission in the solid state at room temperature.