Microporous materials constructed from the interpenetrated coordination networks. Structures and methane adsorption properties

Five new coordination compounds with 4,4'-azopyridine (azpy), [Mn(azpy)(NO3)(2)(H2O)(2)]. BEtOH (1 . 2EtOH), [Co-2(azpy)(3)(No-3)(4)]. Me2CO . 3H(2)O (2 . Me2CO . 3H(2)O), [Co(azpy)(2)(NCS)(2)]. 0.5EtOH (3 . 0.5EtOH), [Cd(azpy)(2)(NO3)(2)].(azpy) (4 azpy), and [Cd-2(azpy)(3)(NO3)(4)]. 2Me(2)CO (5 . 2Me(2)CO), have been synthesized and structurally characterized. The reaction of Mn(NO3)2 . 6H(2)O with azpy in ethanol/acetone affords 1 . 2BEtOH, whose network consists of one-dimensional chains of [Mn(azpy)(H2O)(2)](n). The chains are associated by hydrogen bonding to provide a logcabin-type three-dimensional structure, which creates about 8 x 8 Angstrom of channels, filled with ethanol molecules. The treatment of Co(NO3)(2). 6H(2)O and Co(NCS)(2). 4H(2)O with azpy produces 2 . Me2CO . 3H(2)O and 3 . 0.5EtOH, respectively, which have a brick-wall and a rhombus-type two-dimensional networks. The reaction of Cd(NO3)(2). 4H(2)O with azpy affords 4 azpy from the ethanol/H2O media, while the reaction in the ethanol/acetone media provides 5 . 2Me(2)CO. 4.azpy and 5 . 2Me(2)CO form a square-grid- and a herringbone-type two-dimensional networks, respectively. The two-dimensional sheets of 4 azpy stack without interpenetration, leading to large size of channels, which are filled with free azpy molecules. The two-dimensional networks of 2 . Me2CO . 3H(2)O, 3 . 0.5EtOH, and 5 . 2Me(2)CO are quadruply, doubly, and triply interpenetrated, respectively. Despite the interpenetration, their networks create the microporous channels filled with guest solvent molecules. The dried compounds 2, 3, and 5 adsorb methane between 1 and 36 atm at 25 degrees C, in which 3 and 5 exhibit Langmuir-type isotherms. The inherent micropore volumes for 3 and 5 are 0.685 and 3.30 mmol/g, respectively. XRPD measurements under reduced pressure at 100 degrees C reveal that the channel structure of 3 is the most stable in these compounds; the observed XRPD pattern is in good agreement with that of the simulated pattern of the single-crystal model. Compounds 2 and 5 also retain the porous structures, however, their pore structures are distorted upon loss of guest included molecules.