A New Pillared-layer Framework with Co^Ⅱ 4-Triazole Magnetic Layer Exhibiting Strong Spin-frustration

One new coordination polymer, [Co4(H2 O)4(μ3-OH)2(atz)2(L)]n(1), was solvothermally prepared by the reaction of 3-amino-1,2,4-triazole(Hatz), 4,8-disulfonyl-2,6-naphthalenedicarboxylic acid(H4 L) and Co^Ⅱ salt. It crystallizes in monoclinic system, space group P21/c with a = 10.4454(7), b = 12.2214(8), c = 10.0818(7) ?, b = 102.284(7), V = 1257.56(15) ?~3, Dc = 2.325 g/cm^3, Mr = 880.24, Z = 2, F(000) = 880, μ = 2.859 mm^-1, the final R = 0.0426 and wR = 0.0822 for 5526 observed reflections with I > 2σ(I). Structural analyses indicate that 1 exhibits a three-dimensional(3 D) pillared-layer framework with triazolate extended Co4^Ⅱ layers supported by rigid L^4- connectors. Magnetically, complex 1 displays strong spin-frustrated antiferromagnetism due to the triangular magnetic lattice and cooperative antiferromagnetic couplings mediated by quadruple heterobridges.