Strong antiferromagnetic interaction in a 3D copper–organic framework and spin-glass-like behaviour in a 1D nickel compound

The in situ hydrothermal reaction of 5-(4-carboxy-1H-1,2,3-triazol-1-yl)isophthalic acid (H3ctia) with M(NO3)2·nH2O (M = Cu, Ni) afforded two new coordination polymers, {[Cu4(tia)4(H2O)3]·H2O}n (1) and {Ni(H2O)6·[Ni2(ctia)2(H2O)6]·2H2O}n (2) (tia2− = 5-(1H-1,2,3-triazol-1-yl)isophthalate). X-ray structural analysis reveals complex 1 is an unusual 3D framework containing D4h paddle-wheel copper units and two kinds of mononuclear copper units, and its resulting structure can be rationalized as a new topology with the Schlafli symbol of {4.82}2{42.85.106.122}{82.10}2{83}2. Compound 2 displays a 1D zigzag chain structure. Strong antiferromagnetic interactions are observed among dinuclear units in complex 1. Interestingly, complex 2 exhibits spin-glass-like behaviour with the spin glass freezing temperature at 15.8 K. In addition, the thermal stability of these compounds was also studied.