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

The new bidentate nitrogen-donor ligand 1,4-bis(3-pyridyl)-2,3-diaza-1,3-butadiene ( 4 ) has been synthesized (monoclinic, P 2 1 / c, a = 11.074(2) Å, b = 4.737(1) Å, c = 11.475(2) Å, β = 115.861(9)°, V = 541.7(1) Å 3, 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(NO 3 ) 2 (C 12 H 10 N 4 ) 1.5 ·CH 2 Cl 2 ] n ( 5 ) (monoclinic, P 2 1 / n, a = 7.891(1) Å, b = 17.172(3) Å, c = 18.576(4) Å, β = 97.72(1)°, V = 2494.5(7) Å 3, Z = 4) and [Co(NO 3 ) 2 (C 12 H 10 N 4 ) 1.5 ·CH 2 Cl 2 ] n ( 6 ) (monoclinic, P 2 1 / n, a = 7.7954(8) Å, b = 17.026(3) Å, c = 18.412(3) Å, β = 97.89(1)°, V = 2420.6(6) Å 3, Z = 4). Both 5 and 6 adopt a novel “polycyclohexane” structural motif, consisting of “all-equatorially” condensed cyclohexane-like M 6 (ligand) 6 units. They are open-framework materials with unusually large cavities (ca. 28 × 15 Å), and reversibly absorb and desorb guest molecules between room temperature and 213 °C without framework decomposition.