Strongly fluorescing silver(I) complex of a new thiadiazole ligand: X-ray crystallography, close anagostic interactions and TD-DFT emissive states

Abstract

A new thiadiazole ligand, N-ethyl-5- (benzo[b]thien-2-yl-)-1,3,4-thiadiazol-2-amine (BTH), was prepared from 3-methyl-1-benzofuran-2-carboxylic acid and N-ethylhydrazinecarbothioamide precursors. Corresponding silver(I) complex, tetrakis(N-ethyl-5-(benzo[b]thien-2-yl-)-1,3,4-thiadiazol-2-amine)silver(I) nitrate [Ag2(BTH)4](NO3)2 (1), was prepared. The structures of BTH and 1 were characterized by 1H-NMR, 13C-NMR, FT-IR, elemental analysis and HR-MS techniques. Furthermore, molecular structure of 1 was illuminated by X-ray crystallography. Owing to strong anagsotic interaction, crystal structure of the complex revealed an intriguing asymmetric monomer unit even with two same ligands in 2:1 metal-to-ligand stoichiometry. Photoluminescence properties of the complex were investigated by solid and solution media emission measurements. Excited and emissive state behavior of the complex was further analyzed by quantum chemical TD-DFT calculations and natural transition orbital (NTO) analyses.