• 5-Methyl-tetrazolate;
  • Paramagnetic metal complexes;
  • Copper;
  • Magnetic properties;
  • Spin-flop transition


Two 5-methyl-tetrazolate (mtz)-based paramagnetic metal coordination polymers, {[Cu2(H2O)2(mtz)(μ3-OH)(nip)]·H2O}n (1) and [Cu(H2O)(mtz)2]n (2), were obtained in the presence and absence of aromatic 5-nitroisophathalate (nip2–) coligand by varying the preparation methods. Structural determinations reveal that 1 is a three-dimensional (3D) framework with corner-sharing triangular ribbons infinitely extended by ditopic nip2– connectors. In contrast, 2 is a coplanar (4,4) layer constructed from square-pyramidal CuII ions and μ-N1,N4-mtz linkers, which is further assembled into a 3D supramolecular network by interlayer hydrogen-bonding interactions. Magnetically, spin-frustrated antiferromagnetic ordering is observed in the 3D framework of 1 and canted antiferromagnetic behavior with a slight spin-flop transition is presented in 2, which are structurally resulting from the locally Δ-ribbon in 1 and asymmetric magnetic superexchange mediated by the μ-N1,N4-mtz bridge of 2.