PH-Dependent Cu(II) coordination polymers with tetrazole-1-acetic acid: Synthesis, crystal structures, EPR and magnetic properties

Four novel copper tetrazole-1-acetic acid (Htza) coordination polymers, namely, {[Cu(tza)(2)(Htza)(2)]center dot 2H(2)O}(n) (1), (Cu(tza)(2)](n) (2), {[Cu-4(tza)(4)(CH3COO)(2)(mu(3)-OH)(2)(H2O)(2)]center dot 2H(2)O}(n) (3), and ([Cu-4(tza)(6)(mu(3)-OH)(2)]center dot 4H(2)O}(n) (4), were synthesized as pH-dependent products and characterized by elemental analysis, Fourier transform infrared (FT-IR) spectra, electron paramagnetic resonance (EPR), magnetic properties, and single-crystal X-ray diffraction studies. In 1, two neighboring copper ions are bridged by two carboxylato groups from two tza ligands in a syn(-)anti bridging mode, forming a one-dimensional Cu chain. 2 is a two-dimensional (2D) wavelike layer based on {Cu(tza)}(4) rings from head-to-tail arranged tza ions. 3 and 4 are 2D coordination polymers containing tetranuclear Cu-4(mu(3)-OH)(2) units.