Acetylenedicarboxylate-based cerium(<scp>iv</scp>) metal–organic framework with fcu topology: a potential material for air cleaning from toxic halogen vapors

Abstract

The most contracted cerium(iv)-based metal-organic framework (MOF) with fcu topology incorporating an alkyne-based linker, namely acetylenedicarboxylate (ADC), was synthesized under green conditions in water at room temperature and thoroughly characterized. The structure of this new MOF, denoted as Ce-HHU-1, was determined from powder X-ray diffraction data and Rietveld refinement and is made up of octahedral [Ce₆O₄(OH)₄]¹²⁺ clusters, each of which is connected to other inorganic units by twelve ADC linkers to give a porous network with fcu topology analogous with UiO-66. The permanent microporosity of Ce-HHU-1 was confirmed by nitrogen sorption, meanwhile its high hydrophilicity was displayed by a type I water vapor sorption isotherm. The adsorption of CO₂ in Ce-HHU-1 features a remarkably high zero-coverage isosteric heat of adsorption of 47 kJ mol^-1, attributed to the presence of the -C[triple bond, length as m-dash]C- triple-bond in the framework. The latter also allows for Ce-HHU-1 to capture and irreversibly chemisorb Br₂ vapors, as well as both chemi- and physisorb I₂ vapors in an effective manner, making this material potentially applicable for air cleaning from toxic halogen vapors.