Effect of the Schiff-base-containing triazole ligand and counter anion on the construction of dimeric silver and polynuclear copper complexes

Five new complexes, namely [Ag2(tmat)2(MeCN)2](PF6)2 (1), [Ag2(tmat)4](PF6)2 (2), [Ag2(tmat)4](CF3SO3)2 (3), [Cu3(tmat)6(H2O)6](ClO4)6·4H2O (4) and [Cu4(OH)2(OAc)6(tmat)2]·2H2O (5), have been obtained from the reactions of silver(I) or copper(II) salts with (E)-(thiophen-2-yl)-N-(4H-1,2,4-triazol-4-yl)methanimine (tmat). Complexes 1–3 are based on Ag dimers and have extended solid-state structures formed by different weak interactions. The Ag(I) atoms exhibit a Y-shape coordination geometry in dimeric 1, in which Ag–π and Ag⋯S weak interactions can be found. Complex 2 is constructed from dinuclear [Ag2(tmat)4]2+ cations and PF6− anions, which are further connected to form a quasi-3D structure by C–H⋯F hydrogen bonds. In 3, the Ag(I) atoms exhibit a distorted tetrahedral geometry and rich non-classical weak interactions, such as F⋯S, sustain the packing structure. Complexes 4 and 5 are linear trinuclear and planar tetranuclear complexes, respectively. Complex 5 is an antiferromagnetic complex with Jwb = −77.5 cm−1, Jbb = −33.8 cm−1 (g = 2.0). A discussion of the crystal structures, as well as the coordination properties of the tmat ligands with different counter anions, has been provided.

Graphical abstractA Schiff-base-containing 4-substituted 4H-1,2,4-triazole ligand, (E)-(thiophen-2-yl)-N-(4H-1,2,4-triazol-4-yl)methanimine (tmat), was used to obtain three Ag(I) dimers, a linear trinuclear copper cluster and a tetranuclear planar copper cluster. Rich weak interactions, like Ag–π and other hydrogen bonds, play an important role in forming the structures.Figure optionsDownload full-size imageDownload as PowerPoint slide