engleski

Theoretical Studies of Halogen-Bonded Cocrystallization using Periodic DFT Calculations

Experimental crystal engineering of halogen-bonded organic and metal-organic structures has gained prominence as a route to designing materials with unusualproperties, yielding applications in luminescence, magnetism and data storage. Yet, unlike molecular crystals based on light elements, which have enjoyed immense boost from crystal structure prediction and computational prediction of materials properties, methods for solid-state modelling of halogen-bonded solids have been rather limited, owing to the difficulties in accurately describing the interactions formed by diffuse orbitals of heavy halogen atoms.The key challenge for modelling halogen-bonded solids lies in the presence of diverse supramolecular interactions (hydrogen bonding, π-π stacking etc.), which control the stability of the underlying crystal lattice as much as theactual halogen bond. Therefore, a reliable calculation must balance the contributions of all the interactions present in the crystal structure alongside the halogen bond. This can be achieved withperiodic density functional theory (DFT) calculations, which bring the accuracy of quantum chemical calculations to the realm of crystal structures. We will present application ofperiodic DFT calculations to explain the thermodynamics of solid-state transformations seen in halogen-bonded crystals. We will rationalize the stability of cocrystals withhalogen bonding interactions with the heavy, increasingly metallic elements of the pnictogen group (I...P, I...As, I...Sb). The presentation will follow with the demonstrationof a theoretical prediction of cocrystal stoichiometric interconversions, subsequently verified by experiment. Throughout the presentation we will address the challenges of modelling halogen-bonded crystals and discuss performance of various DFT functionals and dispersion corrections.

Halogen bond ; cocrystallization ; DFT

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