Two nickel(II) bis[(pyridin-2-yl)methyl]amine complexes with homophthalic and benzene-1,2,4,5-tetracarboxylic acids

Abstract

Two new NiII complexes involving the ancillary ligand bis[(pyridin-2-yl)methyl]amine (bpma) and two different carboxylate ligands, i.e. homophthalate [hph; systematic name: 2-(2-carboxylatophenyl)acetate] and benzene-1,2,4,5-tetracarboxylate (btc), namely catena-poly[[aqua{bis[(pyridin-2-yl)- methyl]amine- 3N,N0,N00}nickel(II)]- -2-(2-carboxylatophenyl) aceteto- 2O:O0], [Ni(C9H6O4)(C12H13N3)(H2O)]n, and ( - benzene-1,2,4,5-tetracarboxylato- 4O1,O2:O4,O5)bis(aqua{bis- [(pyridin-2-yl)methyl]amine- 3N,N0,N00}nickel(II)) bis(triaqua{ bis[(pyridin-2-yl)methyl]amine- 3N,N0,N00}nickel(II)) benzene-1,2,4,5-tetracarboxylate hexahydrate, [Ni2(C10H2O8)- (C12H13N3)2(H2O)2] [Ni(C12H13N3)(H2O)3]2(C10H2O8) 6H2O, (II), are presented. Compound (I) is a one-dimensional polymer with hph acting as a bridging ligand and with the chains linked by weak C—H O interactions. The structure of compound (II) is much more complex, with two independent NiII centres having different environments, one of them as part of centrosymmetric [Ni(bpma)(H2O)]2(btc) dinuclear complexes and the other in mononuclear [Ni(bpma)(H2O)3]2+ cations which (in a 2:1 ratio) provide charge balance for btc4 anions. A profuse hydrogen-bonding scheme, where both coordinated and crystal water molecules play a crucial role, provides the supramolecular linkage of the different groups.