Solvothermal synthesis, structures, and gas adsorption properties of two cadmium-organic frameworks

Two cadmium-organic frameworks were synthesized, namely, [Cd(dptz)2]·{Cd[(NH2)2CS]4}·(NO3)4 (1, dptz = 3,6-di-(pyridin-4-yl)-1,2,4,5-tetrazine) and Cd(dpmtz)2 (2, dpmtz = 3,6-di-(pyridin-4-yl)-1,2-dihydro-1-mercapto-1,2,4,5-tetrazine). Compound 1 was obtained by the self-assembly of dptz, Cd(SPh)2 and thiourea under solvothermal conditions. Compound 2 was prepared through an in situ ligand reaction in which generated a new ligand dpmtz only by changing reaction temperature. Compound 1 and 2 were characterized by single-crystal X-ray structure determination, thermogravimetric analysis and powder X-ray diffraction studies. The adsorption behavior shows that compound 2 has selective adsorption capacities of CO2 over N2.