Highly selective CO2/CH4 gas uptake by a halogen-decorated borazine-linked polymerElectronic supplementary information (ESI) available: Characterization methods and gas sorption studies. See DOI: 10.1039/c2jm31123b

A new borazine-linked polymer featuring chlorine-decorated cavities, BLP-10(Cl), has been prepared by the thermal decomposition of benzidine-boron trichloride in toluene under refluxing conditions. BLP-10(Cl) exhibits a moderate Langmuir surface area (1308 m 2 g −1 ) and one of the highest CO 2 /CH 4 selectivities (28.3) by porous materials at 1.0 bar and 273 K. Computational studies revealed that H 2 , CO 2 , and CH 4 interact more favorably with the borazine unit with isosteric heats of adsorption of 7.46, 28.3, and 20.2 kJ mol −1 , respectively. These values are in good agreement with experimental data collected by using the virial method. Results from this study suggest that including highly polarizable and halogenated building units into the framework of porous architectures can significantly enhance their performance in gas separation applications. A new borazine-linked polymer that features chlorine decorated pores has been prepared and exhibits a very high CO 2 /CH 4 selectivity (28) which makes it attractive for use in gas separation applications.