Synthesis, structure, fluorescent and magnetic properties of a series of coordination polymers based on a long and flexible bis-triazole ligand

Abstract

Using the long and flexible bis(4-(4H-1,2,4-triazol-4-yl)phenyl)methane (BTPM) as a ligand, six novel coordination polymers have been synthesized under hydrothermal conditions. {[Zn(BTPM)(HCOO)](NO₃)·2.25H₂O}_n (1) and {[Cd(BTPM)(HCOO)](NO₃)·H₂O}_n (2) exhibit 2D bi-wave layers with one dimensional microchannels of 9 × 9 Ų, which can form 3D supramolecular structures by intermolecular hydrogen bonds. Both {[Zn₂(BTPM)₃(H₂O)₄](NO₃)₄·H₂O}_n (3) and {[Cd₂(BTPM)₃(H₂O)₄](NO₃)₄·3.5H₂O}_n (4) are composed of multiple pairs of interpenetrating (4,4) sheets. {[Cu₈(μ₄–O)(μ₂–H₂O)₂(BTPM)₁₂](ClO₄)₁₄·4H₂O}_n (5) and {[Co₃(BTPM)₃(H₂O)₆](NO₃)₆·7H₂O}_n (6) are 3D interpenetrating frameworks. In complex 5, a rare square planar tetra-coordinate oxygen (ptO) and two different tetranuclear copper(II) clusters, [Cu₄(μ₂–H₂O)₂N₂₀] and [Cu₄(μ₄–O)N₂₀], have been observed. Complex 6 shows a 6-connected topology based on linear trinuclear clusters. The fluorescent properties of 1–4, as well as the magnetic properties of 5 and 6 are studied.