Rational assembly and luminescence properties of 2 and 3D organometallic networks using silver(i) 4-pyridylethynide and 5-pyrimidylethynide complexes as building units

Abstract

4-Ethynylpyridine and 5-ethynylpyrimidine were utilized as ligands to synthesize three novel silver–ethynide complexes [(4-Py-C₂Ag)₃·6CF₃CO₂Ag·2H₂O] (1), [(4-Py-C₂Ag)₂·4AgNO₃] (2) and [(5-Pyrim-C₂Ag)·3AgNO₃·H₂O] (3). In both 1 and 2, the [4-C₅H₄N(CC)Ag₄]³⁺ units aggregate to generate linear silver chains through silver–ethynide and argentophilic interactions, which are further connected through Ag–N(pyridyl) coordination bonds to afford 2D grids, and finally linked by trifluoroacetate or nitrate groups to form a rigid 3D coordination network. However in 3, each [5-C₄H₃N₂(CC)Ag₄]³⁺ unit interacts with two other units through Ag–N(pyrimidyl) bonds to construct 2D honeycomb-like networks, and are also further connected by nitrate groups to generate a 3D network. It is demonstrated that the coordination modes of organic ligands play a key role in controlling the structures of the organometallic networks based on silver–ethynide complexes.