Two-dimensional divalent metal/pimelate coordination polymers incorporating dipodal organodiimines: Crystal structures, thermal properties, and magnetic studies

Hydrothermal synthesis has afforded a series of 2-D coordination polymers incorporating the flexible alpha,omega-dicarboxylate pimelate ligand (pim) and either the kinked organodiimine 4,4'-dipyridylamine (dpa) or its conformationally flexible congener 1,3-di-4-pyridylpropane (dpp). [M(pim)(dpa)(H2O)], (M = CO, 1-Co; M = Ni, 1-Ni) both display puckered (4,4) rhomboid grid-like 2-D layers that aggregate into 3D through O-H center dot center dot center dot O hydrogen bonding. {[Cu-2(Pim)(2)(dpa)(2)] center dot 5H(2)O}(n) (2) possesses 2-D slab motifs constructed from the linkage of [Cu-2(pimelate)(2)](n) ribbons and [Cu(pimelate)], double chains through dpa tethers, entraining discrete water molecule chains with D(8) classification. Employing the longer dpp tether resulted in [Ni(pim)(dpp)], (3), which manifested a doubly interpenetrated 2-D (4,4) grid layer morphology. Analysis of the variable temperature magnetic susceptibility of 1-Ni indicated the presence of zero-field splitting as well as possible weak antiferromagnetic coupling between Ni atoms in adjacent layer subunits. In contrast, 2 manifested apparent intradimer ferromagnetic interactions with underlying interdimer antiferromagnetic coupling. (c) 2007 Elsevier Ltd. All rights reserved.