Seven 3d-4f coordination polymers of macrocyclic oxamide with polycarboxylates: Syntheses, crystal structures and magnetic properties

Seven new 3d-4f heterometallic coordination polymers, [Ln(CuL)(2)(Hbtca)(btca)(H2O)] center dot 2H(2)O (Ln = Tb-III 1, Pr-III 2, Sm-III 3, Eu-III 4, Yb-III 5), [Nd(NiL)(nip)(Rnip)] center dot 0 center dot 25H(2)O center dot 0.25CH(3)OH (R= 0.6CH(3), 0.4H) 6 and [Nd-2(NiL)(niP)(3)(H2O)] center dot 2H(2)O 7(CuL or NiL, H2L = 2, 3-dioxo-5, 6, 14, 15-dibenzo-1, 4, 8, 12-tetraazacyclopentadeca-7, 13-dien; H(2)btca = benzotriazole-5-carboxylic acid; H2nip = 5-nitroisophthalic acid) have been synthesized by a solvothermal method and characterized by single-crystal X-ray diffraction. Complexes 1-5 exhibit a double-strand meso-helical chain structures formed by [Ln(III)Cu2(II)] units via the oxamide and benzotriazole-5-carboxylate bridges, while complex 6 exhibits a four-strand meso-helical chain formed by NdNi unit via the oxamide and 5-nitroisophthalate bridges. Complex 7 consists of a 2D layer framework formed by four-strand meso-helical chain via the nip(2-) bridges. Moreover, the magnetic properties of them were investigated, and the best-fit analysis of chi T-M versus T show that the anisotropic contribution of Ln(III) ions (arising from the spin-orbit coupling or the crystal field perturbation) dominates (weak exchange limit) in these complexes(for 3, lambda = 214.6 cm(-1), zj' = -0.33 cm(-1), g(av) = 1.94; for 5, Delta = 6.98 cm(-1), zj' = 1.53 cm(-1), g(av) = 1.85). (C) 2016 Elsevier Inc. All rights reserved.