engleski

Halogen-bonded complexes of perhalogenated hydrocarbons and benzoyl-4-pyridoylmethane

Halogen bond is an attractive interaction between an electrophilic region on a halogen atomin a molecular entity (halogen bond donor) and a nucleophilic region in another, or the same, molecular entity (halogen bond acceptor). [1] Alongside hydrogen bond, it is a widely used tool for constructing supramolecular assemblies in the solid state, where perhalogenated hydrocarbons have been highlighted as the most important halogen bond donors.[2] On the other hand, potential of using  -diketones for the synthesis of a halogenbonded structures in the solid state has scarcely been investigated to date, indicated by only 6 structures deposited with the CSD.[3] In this contribution we are presenting crystal structures of a novel asymmetric −diketone, benzoyl-4-pyridoylmethane (b4pm) and cocrystals derived from b4pm and five usual halogen bond donors: iodopentaflourobenzene (ipfb), 1, 2-, 1, 3- and 1, 4-diiodotetraflorobenzene (1, 2-tfib, 1, 3-tfib and 1, 4-tfib) and 1, 3, 5-triiodo-2, 4, 6- trifluorobenzene (1, 3, 5-titfb). These binary solids have been prepared both by crystallization from solution and liquid- assisted grinding (LAG). All five cocrystals are assembeled by C—I···N halogen bonds involving pyridyl nitrogen and iodoperfluorobenzene iodine. Furthermore, cocrystals derived from 1, 3-tfib or 1, 2-tfib have additional C—I···O halogen bonds, involving oxygen atoms from  -diketo group and the other iodine atom. Most of the obtained cocrystals contain one b4pm molecule connected to a corresponding halogen bond donor, except for (b4pm)2(1, 4-tfib), where stoichiometry is 2:1 as a result of 1, 4-tfib bridging two diketone molecules via C—I···N halogen bonds. All obtained compounds have been characterized by X-ray powder diffraction, thermogravimetry and differential scanning calorimetry.

halogen bonding, cocrystals, perhalogenated hydrocarbons, benzoyl-4- pyridoylmethane

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