Synthesis and adsorption properties of new calcium metal-organic framework (Ca-MOF) ZIOC-10 based on a new carbazole linker

A carbazole-based linker 9-(carboxymethyl)carbazole-3,6-dicarboxylic acid (H3cbzac) was synthesized for the first time. Its structure was confirmed via 1H NMR and Powder X-Ray Diffraction (PXRD) methods. A novel calcium-based 2D MOF Ca(H2cbzac)2(DMF)2 (ZIOC-10) was synthesized via a solvothermal procedure. It was found that the obtained framework undergoes several structural changes upon heating, which lead to the formation of a new framework Ca(H2cbzac)2 (ZIOC-10a). Noteworthy, ZIOC-10 transforms into the permanent porous (524 m2/g) 3D framework, which can absorb methane, ethane, propane, and carbon dioxide at room temperature. [Display omitted] •New carbazole based carboxylic acid H3cbzac or (9-(carboxymethyl)carbazole-3,6-dicarboxylic acid) was synthesized for the first time.•A novel calcium-based 2D MOF Ca(H2cbzac)2(DMF)2 (ZIOC-10) was synthesized via a solvothermal procedure.•It was found that obtained 2D MOF transforms into new 3D MOF structure (Ca(H2cbzac)2 or ZIOC-10a) when heated in vacuum.•ZIOC-10a exhibits permanent porosity and relatively large surface area (524 m2/g) compared to other known Ca-MOFs.•The adsorption of gases (CO2, CH4, C2H6 and C3H8) was studied on the obtained ZIOC-10a material.