Construction of [Ag2X2]-based complexes from reactions of Ag(i) salts with N-diphenylphosphanylmethyl-4-aminopyridine: isolation, structures, and luminescent properties

Abstract

Reactions of N-diphenylphosphanylmethyl-4-aminopyridine (dppmapy) with K[Ag(CN)₂], Ag(dca) (dca = dicyanamide), AgSCN, AgCl, AgBr or AgI gave rise to six [Ag₂X₂]-based (X = CN⁻, dca, SCN⁻, Cl⁻, Br⁻ and I⁻) compounds, [{Ag₂(CN)₂(dppmapy)}·0.5CHCl₃]_n (1), [Ag₂L₂(dppmapy)₂]_n (2: L = dca; 3: L = SCN), [{Ag₂L₂(dppmapy)₂}·sol]_n (4: L = Cl, sol = 0.5MeOH·0.5CH₂Cl₂; 5: L = Br, sol = 2CHCl₃), and [Ag₂I₂(dppmapy)₄]·3MeOH (6). Complexes 1–6 were characterized by elemental analysis, IR, powder X-ray diffraction (PXRD), and single crystal X-ray diffraction. Compound 1 has a one-dimensional (1D) spiral chain constructed by bridging the [(CN)Ag(μ-CN)Ag] fragments via dppmapy ligands. In 2, 3 and 4, each [Ag₂X₂] (X = dca, SCN, Cl) fragment is linked by dppmapy bridges to the other two equivalent ones to form a 1D chain containing 16-membered rings (2) or a 1D double chain containing 20-membered rings (3) or a 1D spiral chain containing 20-membered rings (4). Compound 5 possesses a two dimensional (2D) (4,4) network consisting of 36-membered metallomacrocycles in which each [Ag₂Br₂] fragment acts as a unique planar four-connecting node to link the other four equivalent ones via dppmapy bridges. Complex 6 has a [Ag₂I₂] unit with a pair of monodentate dppmapy ligands coordinated at each Ag center. The photoluminescent properties of 1–6 in the solid state at ambient temperature were also investigated.