Architectural alterations from 1D to 3D coordination polymers based on a pair of isomeric linear and V-shaped triazole/thiophene/triazole bridging ligands

Four pairs of transition-metal [Co(II), Zn(II), Ni(II) and Cu(I)] coordination polymers have been prepared and characterized based on a pair of isomeric linear and V-shaped rigid thiophene-centered ditriazole bridging ligands [2,5-di(1H-1,2,4-triazol-1-yl)thiophene (L1) and 3,4-di(1H-1,2,4-triazol-1-yl)thiophene (L2)]. They are formulated as {[Co(L1)2(H2O)2](ClO4)2}n (1), {[Zn(L1)2(H2O)2](ClO4)2}n (2), {[Ni(L1)2(H2O)2](ClO4)2}n (3), {[Co(L2)2(H2O)2](ClO4)2}n (4), {[Zn(L2)2(H2O)2](ClO4)2}n (5), {[Ni(L2)2(H2O)2](ClO4)2}n (6), [Cu(L1)(CN)]n (7) and [Cu2(L2)(SCN)2]n (8), where distinct metal/ligand ratios (1:2, 1:1 and 2:1) and dimensions [one-dimensional (1D), two-dimensional (2D) and three-dimensional (3D)] have been observed because of the alterations of the coordination modes of central metal ions, the shape and conformation of ligands and the participancy of counterions. X-ray single-crystal diffraction analyses reveal that 1D chains have been formed in the cases of 4–6, while 2D planes have been built in 1–3. In contrast, 3D networks have been constructed in 7 and 8 with different topologies because of the further linkage of CN− and SCN− counterions.

Graphical abstractFour pairs of 1D, 2D and 3D transition-metal coordination polymers 1–8, based on two isomeric linear and V-shaped thiophene-based ditriazole bridging ligands, display abundant structural diversity.Figure optionsDownload full-size imageDownload as PowerPoint slide