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, P2(1)/c, a = 11.074(2) Angstrom, b = 4.737(1) Angstrom, c = 11.475(2) Angstrom, beta = 115.861(9)degrees, V = 541.7(1) Angstrom(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(NO3)(2)(C12H10N4)(1.5). CH2Cl2](n) (5) (monoclinic, P2(1)/n, a = 7.891(1) Angstrom, b = 17.172(3) Angstrom, c = 18.576(4) Angstrom, beta = 97.72(1)degrees, V = 2494.5(7) Angstrom(3), Z = 4) and [Co(NO3)(2)(C12H10N4)(1.5). CH2Cl2](n) (6) (monoclinic, P2(1)/n, a = 7.7954(8) Angstrom, b = 17.026(3) Angstrom, c = 18.412(3) Angstrom, beta = 97.89(1)degrees, V = 2420.6(6) Angstrom(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 x 15 Angstrom), and reversibly absorb and desorb guest molecules between room temperature and 213 degrees C without framework decomposition.