Received 14 October 2010
The components of the title 1:1 co-crystal, C14H10N4·C6F4I2, are connected via an NI [2.959 (4) Å] halogen bond, in which the N atom is part of the relatively electron-rich pyrazine ring. The C6F4I2 molecule is almost planar [r.m.s. deviation = 0.038 Å] but there are significant twists in the pyrazine derivative, as seen in the dihedral angles [31.3 (2) and 54.6 (2)°] formed between the pendant pyridyl rings and the central pyrazine ring. The bimolecular aggregates are sustained in the crystal by C-HF and - interactions [ring centroid(pyridyl)-ring centroid(benzene) = 3.678 (3) Å].
For related studies on co-crystal formation, see: Broker & Tiekink (2007); Broker et al. (2008); Arman et al. (2010). For background to halogen bonding, see: Metrangolo et al. (2008); Pennington et al. (2008).
Data collection: CrystalClear (Molecular Structure Corporation & Rigaku, 2005); cell refinement: CrystalClear; data reduction: CrystalClear; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 (Farrugia, 1997) and DIAMOND (Brandenburg, 2006); software used to prepare material for publication: publCIF (Westrip, 2010).
Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: HB5683 ).
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