Gas sorption studies were undertaken using a Micromeritics Instrument Corporation (Norcross, Georgia, USA) ASAP 2020 system. Approximately 100 -150 mg of the corresponding solid product was transferred to a pre-weighed sample tube and evacuated under vacuum at 100°C on the gas adsorption apparatus until the outgas rate was <5 μmHg. All gases used were of 99.999% purity. Helium was used for the free space determination after sorption analysis. Adsorption isotherms of N2 and H2 were measured at 77 K in a liquid nitrogen bath. Adsorption isotherms of CO2 and CH4 were measured at 273 K and 298 K in methanol bath controlled by circulating refrigerated medium. Pore size distributions were calculated using the NLDFT model implemented in the ASAP 2020 software.