title: Halogen bonds on demand: I···S contacts in cocrystals of trans-bis(thiocyanato-κN)tetrakis(4-vinylpyridine-κN)nickel(II) and 2,3,5,6-tetrafluoro-1,4-diiodobenzene.
abstract: Hydrogen bonds are considered a powerful organizing force in designing supramolecular architectures because they are directional, selective and reversible at room temperature. trans-Dithiocyanatotetrakis(4-vinylpyridine)nickel(II) is a popular host for the inclusion of small molecules and 2,3,5,6-tetrafluoro-1,4-diiodobenzene (TFDIB) represents a strong halogen-bond donor. These constituents cocrystallize in a 1:1 stoichiometry, [Ni(NCS)2(C7H7N)4]·C6F4I2, in the tetragonal space group I4₁/a. Both residues occupy special positions, i.e. the pseudo-octahedral Ni(II) complex is located on a twofold axis and the TFDIB molecule sits about a crystallographic centre of inversion. The components interact via a short S···I contact of 3.2891 (12) Å between the thiocyanate S atom of the host and the iodine substituent at the perhalogenated aromatic ring of the smaller guest molecule. This interaction meets the commonly accepted criteria for a halogen bond. Such halogen bonds to sulfur are significantly less common than to smaller electronegative atoms.
authors.affiliation: Faculty of Applied Chemistry and Materials Science, University Politehnica of Bucharest, Polizu 1, RO-011061 Bucharest, Romania.
authors.forename: Mihaela-Diana
authors.initials: MD
authors.lastname: Şerb
authors.affiliation: Institut für Anorganische Chemie, RWTH Aachen, Landoltweg 1, 52074 Aachen, Germany.
authors.forename: Carina
authors.initials: C
authors.lastname: Merkens
authors.affiliation: Institut für Anorganische Chemie, RWTH Aachen, Landoltweg 1, 52074 Aachen, Germany.
authors.forename: Irmgard
authors.initials: I
authors.lastname: Kalf
authors.affiliation: Institut für Anorganische Chemie, RWTH Aachen, Landoltweg 1, 52074 Aachen, Germany.
authors.forename: Ulli
authors.initials: U
authors.lastname: Englert
keywords: 4-vinylpyridine; Hirshfeld surface analysis; S...I contact; cocrystal; crystal structure; halogen bond; nickel complex; tetrafluorodiiodobenzene