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From Molecules to Materials: Engineering New Ionic Liquid Crystals Through Halogen Bonding
Published on: March 24, 2018
Higher-order metal-organic halogen-bonded cocrystals relying on a single supramolecular synthon
Lidija Posavec1, Anuj Tripathi2, Stefano Canossa3
1University of Zagreb Faculty of Science, Department of Chemistry Horvatovac 102a Zagreb Croatia dominik@chem.pmf.unizg.hr.
Abstract:
A proof-of-principle study is outlined for the construction of multicomponent metal-containing solids, i.e. three- and four component metal-organic halogen-bonded cocrystals (MOXB) based exclusively on I⋯S halogen bonds. This research represents a curiosity-driven exploration that yielded highly significant observations regarding the ability of the metal-organic multitopic acceptor to simultaneously engage in halogen bonding with a large number of halogen bond donors (up to five) due to the presence of an acceptor species, the isothiocyanate sulfur atom, which forms a robust I⋯SCN synthon. The effectiveness of this exploration is proven by the synthesis of a unique family of four ternary and one quaternary cocrystal using a Ni(ii) coordination compound, Ni(4-methylpyridine)4(NCS)2, and three perfluorinated iodobenzenes. All cocrystals were obtained as crystallization products from a solution of three (or four) reactants. Periodic density-functional theory calculations have been conducted to assess the formation energies of the obtained cocrystals and the strengths of the established intermolecular interactions. The presented research indicates significant potential of MOXB cocrystals in the efficient synthesis of higher-order cocrystals based solely on halogen bonds and could serve as the basis for an approach to designing higher-order cocrystals in general.
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