Session: COMP Poster Session:

Metal-organic frameworks (MOFs) have shown promise for gas storage and sequestration applications storage on account of their large surface to volume ratio and modularity in structural and chemical composition. In-silico prediction of adsorption equilibria is a cost-effective means of obtaining quantitative predictions and insight on metal-adsorbate binding in a MOF. Given a large number of candidate structures, quantum chemical calculations can suggest promising storage materials as synthetic targets. To ensure accurate description of the critical local chemistry, we employ the ωB97M-V functional, which is an accurate range-separated hybrid metaGGA that includes non-local VV10 dispersion, designed by the combinatorial ``survival of the most transferable'' protocol. Using energy decomposition analysis, we unravel the nature of the binding to reveal the chemical influences at play in metal-ligand interactions across framework families. Our findings suggest multiple hydrogen binding can be a tractable route towards enhancing volumetric storage in a MOF. To add to pore size and framework topology as key variables in rational framework design, we identify charge transfer as a significant driver in chemical handle-based gas separations.

Significant forward-donation orbitals for H2 binding to Vanadium in a MOF. Notice the sigma symmetry across the binding (z)-axis in these orbitals.

Significant forward-donation orbitals for H2 binding to Vanadium in a MOF. Notice the sigma symmetry across the binding (z)-axis in these orbitals.

Back-donation from V(II) to H2 in a MOF occurs via molecular orbitals that show d(π) symmetry at the metal site.

Back-donation from V(II) to H2 in a MOF occurs via molecular orbitals that show d(π) symmetry at the metal site.

Martin Head-Gordon

Univ of California

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