title: Unraveling Interactions in Molecular Crystals Using Dispersion Corrected Density Functional Theory: The Case of the Epoxydihydroarsanthrene Molecules.
abstract: Noncovalent interactions are prevalent in crystal packing and supramolecular chemistry. Directional noncovalent interactions such as donor-acceptor bonds (e.g., hydrogen, chalcogen, and pnictogen bonds) as well as nondirectional forces (such as dispersion) come together to stabilize supramolecular assemblies by striking a delicate energetic balance. Typically, a two-pronged approach employing experimental X-ray structures and gas phase quantum chemical modeling has been used to understand and design supramolecular architectures. Drawing from recent advances in molecular crystal modeling with dispersion corrected density functional theory (DFT), we propose in this article a combination of qualitative noncovalent index (NCI) analysis and periodic and gas phase DFT calculations on substitutional crystal analogues to unravel the dominant interactions in a particular crystal packing. We illustrate the possibilities of this approach by studying three crystal packings of epoxydihydroarsanthrene analogues that present a complex combination of donor-acceptor interactions including pnictogen-pnictogen, pnictogen-π, and pnictogen-chalcogen. We show that, in these crystals, the chalcogen-pnictogen interaction dominates over the pnictogen-pnictogen and pnictogen-π. In the latter, the role of donor and acceptor is reversed depending on the interacting moieties. Multiple chalcogen-pnictogen interactions necessitate larger donor atoms, such as sulfur. These observations explain and rationalize the experimentally observed crystal structures.
authors.affiliation: National Institute for Nanotechnology, National Research Council of Canada , 11421 Saskatchewan Drive, Edmonton, Alberta, Canada T6G 2M9.
authors.forename: A
authors.initials: A
authors.lastname: Otero-de-la-Roza
authors.affiliation: Departamento de Química Física y Analítica, Facultad de Química, Universidad de Oviedo , 33006 Oviedo, Asturias, Spain.
authors.forename: Víctor
authors.initials: V
authors.lastname: Luaña
authors.affiliation: Department of Chemistry, University of Malaya , 50603 Kuala Lumpur, Malaysia.
authors.forename: Edward R T
authors.initials: ER
authors.lastname: Tiekink
authors.affiliation: Laboratório de Cristalografía Estereodinâmica e Modelagem Molecular, Departamento de Química, Universidade Federal de São Carlos , São Carlos, SP 13565-905, Brazil.
authors.forename: Julio
authors.initials: J
authors.lastname: Zukerman-Schpector