Two polymeric structures with a benzene-1,2,4,5-tetracarboxylate ligand acting in μ₂- and μ₄-bridging modes

Abstract

catena-Poly[[tetraaquabis(1H-pyrazole-kappaN(2))nickel(II)] [[diaquabis(1H-pyrazole-kappaN(2))nickel(II)]-mu-benzene-1,2,4,5-tetracarboxylato-kappa(2)O(1):O(4)] tetrahydrate], {[Ni(C(3)H(4)N(2))(2)(H(2)O)(4)][Ni(C(10)H(2)O(8))(C(3)H(4)N(2))(2)(H(2)O)(2)].4H(2)O}(n), (I), and poly[[(mu(4)-benzene-1,2,4,5-tetracarboxylato-kappa(4)O(1):O(2):O(4):O(5))octakis(1H-pyrazole-kappaN(2))dicobalt(II)] tetrahydrate], {[Co(2)(C(10)H(2)O(8))(C(3)H(4)N(2))(8)].4H(2)O}(n), (II), are polymeric compounds crystallizing in the space group P1, with two independent metallic cations and one benzene-1,2,4,5-tetracarboxylate (btc) anion, each lying on symmetry centres. Individual coordination polyhedra are regular and the main differences are in the way the btc anion binds [mu(2) in (I) and mu(4) in (II)], promoting a 'chain-like' one-dimensional structure in (I) and a 'sieve-like' two-dimensional motif in (II).