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.
ACTA CRYSTALLOGRAPHICA SECTION C-STRUCTURAL CHEMISTRY 2015;
71:991-5. [PMID:
26524173 DOI:
10.1107/s2053229615019002]
[Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2015] [Accepted: 10/08/2015] [Indexed: 11/10/2022]
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.
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