In-Situ Ligand Formation-Driven Preparation of a Heterometallic Metal-Organic Framework for Highly Selective Separation of Light Hydrocarbons and Efficient Mercury Adsorption

By means of the in situ ligand formation strategy and hard soft acid base (HSAB) theory, two types of independent In(COO)(4) and Cu6S6 clusters were rationally embedded into the heterometallic metal organic framework (HMOF) {[(CH3)(2)NH2]InCu4L4.xS}(n) (BUT-52). BUT-52 exhibits a three-dimensional (3D) anionic framework structure and has sulfur decorating the dumbbell-shaped cages with the external edges of 24 and 14 A by the internal edges. Remarkably, because of the stronger charge-induced interactions between the charged MOF skeleton and the easily polarized C-2 hydrocarbons (C(2)s), BUT-52 was used for C(2)s over CH4 and shows both high adsorption heats of C(2)s and selective separation abilities for C(2)s/CH4. Furthermore, BUT 52 also displays efficient mercury adsorption resulting from the stronger-binding ability beween the sulfur and the mercury and can remove 92% mercury from methanol solution even with the initial concentration as low as 100 mg/L. The results in this work indicate the feasibility of BUT-52 for the separation of light hydrocarbons and efficient adsorption/removal of mercury.