Divalent Metal Succinate/4,4‘-Dipyridylamine Extended Solids: From Helical Chains to Diverse Three-Dimensional Networks Featuring Double, Quadruple, or Self-Interpenetration

Abstract

Hydrothermal synthesis has afforded a family of five divalent metal succinate (suc) coordination polymers incorporating the kinked dipodal organodiimine 4,4'-dipyridylamine (dpa), which were structurally characterized by single-crystal X-ray diffraction and thermogravimetric analysis. [Co(suc)(dpa)2] (1) manifests chiral helical one-dimensional (1-D) chains formed from the linkage of neighboring Co atoms through bischelating bisbridging succinate moieties, with pendant dpa ligands. {[Ni(dpa)2(suc)0.5]Cl} (2) possesses a rare self-interpenetrated 5-connected cationic framework with a unique 610 topology, constructed from the junction of quadruply interpenetrated adamantoid [Ni(dpa)2]2n+ networks via bischelating μ2-succinate ligands. {[Cu(suc)(dpa)]·0.5H2O} (3) exhibits a doubly interpenetrated CdSO4 net (658 topology) containing both 1-D double braided cationic helical [Cu(dpa)]2+ ribbons and orthogonally situated zigzag [Cu(suc)] chains. The quadruply interpenetrated three-dimensional (3-D) network structure (42638 topology, SrAl2-type) of {[Zn(suc)0.5/2(dpa)]·H2O} (4) is built from [Zn(suc)0.5/2] chains interlocked with dpa tethers. {[Cd(suc)(dpa)]·H2O} (5) displays doubly interpenetrated 6-connected α-Po networks based on {Cd2O2} dimers within [Cd(suc)] two-dimensional (2-D) layers, in turn pillared by dpa ligands. The coordination geometry about the metal atoms and the succinate binding modes and conformations in these compounds vary widely, playing a significant role in promoting the diversity of the observed structural motifs. Supramolecular hydrogen-bonding interactions through the dpa amine subunit are evident in all cases.