Novel flexible bis-triazole bridged copper(ii) coordination polymers varying from one- to three-dimensionality

Abstract

A new family of coordination polymers, [Cu(btm)₂(ClO₄)₂]_n (1, btm = 1,2-bis(1,2,4-triazol-1-yl)methane), {[Cu(bte)₂(ClO₄)(H₂O)](ClO₄)(H₂O)₂}_n (2, bte = 1,2-bis(1,2,4-triazol-1-yl)ethane), {[Cu(btp)₂(H₂O)₂](ClO₄)₂(H₂O)_1.5}_n (3, btp = 1,3-bis(1,2,4-triazol-1-yl)propane) and {[Cu(btb)₂(H₂O)₂](ClO₄)₂}_n (4, btb = 1,4-bis(1,2,4-triazol-1-yl)butane) have been prepared under hydrothermal conditions and characterized by elemental analyses, IR, thermogravimetric and X-ray structural analyses. The bis(triazole) ligands with different spacer lengths exhibit conformational flexibility and lead to the generation of diversified architectures. 1 and 2 show as one-dimensional (1D) chains. 3 shows as two-dimensional (2D) rectangular networks with a (4,4) topology, which contain 2D planar nanogrid networks stacked in a step stacking fashion. Weak O⋯H–C and N⋯H–C hydrogen bonds reside among these 2D layers, which link the 2D layers to lead to a 3D supramolecular architecture. 4 is a 3D MOF with large 1D rhombic channels with dimensionalities of 14.16 × 10.92 Ų accommodating ClO₄⁻ anions, which has a 3D diadiamond network with one point, {6⁶}. Their EPR spectra have also been investigated in the solid state.