Syntheses, structures and photoluminescent properties of a series of Ag(i) coordination architectures based on 2,4-diamino-6-methyl-1,3,5-triazine and dicarboxylates: from a 0D discrete molecule to a 3D infinite network

Abstract

Five mixed-ligand Ag(I) coordination complexes (CCs), namely, [Ag₂(dmt)₂(suc)·H₂O]_n (1), [Ag₂(dmt)₂(suc)(H₂O)·0.5H₂O] (2), [Ag₂(dmt)₂(glu)]_n (3), [Ag₂(dmt)₂(adip)]_n (4), and [Ag₂(dmt)₂(tpa)]_n (5) (dmt = 2,4-diamino-6-methyl-1,3,5-triazine, H₂suc = succinic acid, H₂glu = glutaric acid, H₂adip = adipic acid, H₂tpa = terephthalic acid), have been synthesized through a one-pot ultrasonic reaction of AgNO₃, dmt and different dicarboxylates and characterized by elemental analysis, IR spectroscopy, and X-ray single-crystal diffraction. Complexes 1 and 2 formed in different solvent systems (methanol/acetonitrile for 1 and methanol/ethanol for 2) exhibit a two-dimensional (2D) sheet and a zero-dimensional (0D) tetranuclear motif, respectively. Different solvent systems influence the coordination modes (μ₂-N,N′ for 1 and μ₁-N for 2) of dmt and the conformations (anti for 1 and gauche for 2) of the suc anion; as a result, two diverse structures are produced. Complex 3 is a one-dimensional (1D) chain structure running along the a axis constructed from the [Ag₂(μ₁-dmt)₂] subunit and the gauche–gauche μ₅-η¹:η¹:η¹:η² glu ligand. Similarly, complex 4 is also a 1D chain structure, but the adip ligand adopts an anti–anti–anti conformation to link the [Ag₂(μ₁-dmt)₂] subunit to complete the 1D chain. Complex 5 is a complicated 3D framework built from a tetrahedral Ag(I) center, a quadridentate tpa and an angular bidentate dmt ligand which can be simplified as a new (2,4,4)-connected 3-nodal net with the Schläfli symbol of {4.8⁴.12}₂{4².8².10²}{8}₂. The results show that the dicarboxylate and the solvent system play crucial roles in the formation of the resulting structures. Additionally, results about thermogravimetric curves and photoluminescence spectra were discussed.