Impact of Pore Size and Defects on the Selective Adsorption of Acetylene in Alkyne-Functionalized Nickel(II)- Pyrazolate-Based MOFs

J.A.R.N. thanks EU Feder funding, MINECO (CTQ2017-84692-R) and Junta de Andalucia (P18-RT-612). S.S. thanks the Erasmus+ (Placement) and the University of Milan for funding her stay in Granada. V.C. thanks the Italian Ministry of University and Research is acknowledged for financial support through the PRIN 2107 Program (Project 2017KKP5ZR). E.R.M. thanks UGR for a research contract. A.M. and F.A. thank Tarbiat Modares University for funding support.C2H2/CO2 separation is a highly challenging process as a consequence of their similar physicochemical properties. In this work we have explored, by static and dynamic gas sorption techniques and computational modelling, the suitability of a series of two isoreticular robust Ni(II)pyrazolatebased MOFs, bearing alkyne moieties on the ligand backbones, for C2H2/CO2 separation. The results are consistent with high adsorption capacity and selectivity of the essayed systems towards C2H2 molecules. Furthermore, a post-synthetic treatment with KOH ethanolic solution gives rise to linker vacancy defects and incorporation of extraframework potassium ions. Creation of defects is responsible for increased adsorption capacity for both gases, however, strong interactions of the cluster basic sites and extraframework potassium cations with CO2 molecules are responsible for a lowering of C2H2 over CO2 selectivity.European Commission Spanish Government CTQ2017-84692-RJunta de Andalucia P18-RT-612Erasmus+ (Placement)University of MilanMinistry of Education, Universities and Research (MIUR) 2017KKP5ZRUGRTarbiat Modares Universit