Post-synthetic modification of tetrazine functionalized porous MOF for CO2 sorption performances modulation

Post-Synthetic Modification (PSM) is an important and efficient method to regulate and control properties of metal-organic framework (MOF). Herein, a series of PSM derivatives were constructed originating from the inverse-electron demand Diels−Alder (IEDDA) reaction of tetrazine moiety of a microporous MOF dptz-CuTiF6 and alkynyl reagents. Through the screening of different alkynyl reagents, MOFs with modified pore chemistry and tuned gas adsorption properties were obtained. 3-butyn-2-one-dptz-CuTiF6 exhibits a milder CO2 isosteric heat of adsorption (34.2 ​kJ ​mol−1) without lower CO2 adsorption capacity due to the repulsive interaction between introduced oxygen-containing groups and CO2. Besides, higher adsorption capacity of CO2 (105.3 ​cm3 ​g−1 and 65.5 ​cm3 ​g−1 at 1 ​bar and 0.1 ​bar) was achieved with oct-4-yne-dptz-CuTiF6 because of the increased stability due to the successful modification of hydrophobic groups on the surface of the framework. [Display omitted] •The post-synthetic modification derivatives of MOF dptz-CuTiF6 ​were achieved and show higher CO2 ​adsorption capacity.•The pore structure and pore chemistry of dptz-CuTiF6 is well modified with the PSM reactions.•Higher CO2 adsorption capacity and milder CO2 isosteric heat of adsorption have been achieved with the PSM derivatives.