A Novel Noninterpenetrating Polycyclohexane Network: A New Inorganic/Organic Coordination Polymer Structural Motif Generated by Self-Assembly of “T-Shaped” Moieties

Abstract

The new bidentate nitrogen-donor ligand 1,4-bis(3-pyridyl)-2,3-diaza-1,3-butadiene (4) has been synthesized (monoclinic, P21/c, a = 11.074(2) A, b = 4.737(1) A, c = 11.475(2) A, β = 115.861(9)°, V = 541.7(1) A3, Z = 4) and its coordination chemistry with cadmium and cobalt nitrate hydrates investigated. Two new noninterpenetrating coordination polymers based on “T-shaped” building blocks have been obtained: [Cd(NO3)2(C12H10N4)1.5·CH2Cl2]n (5) (monoclinic, P21/n, a = 7.891(1) A, b = 17.172(3) A, c = 18.576(4) A, β = 97.72(1)°, V = 2494.5(7) A3, Z = 4) and [Co(NO3)2(C12H10N4)1.5·CH2Cl2]n (6) (monoclinic, P21/n, a = 7.7954(8) A, b = 17.026(3) A, c = 18.412(3) A, β = 97.89(1)°, V = 2420.6(6) A3, Z = 4). Both 5 and 6 adopt a novel “polycyclohexane” structural motif, consisting of “all-equatorially” condensed cyclohexane-like M6(ligand)6 units. They are open-framework materials with unusually large cavities (ca. 28 × 15 A), and reversibly absorb and desorb guest molecules between room temperature and 213 °C wi...