Crystal structure of cyclo-tris(μ-3,4,5,6-tetrafluoro-o-phenylene-κ2 C 1:C 2)trimercury-tetracyanoethylene (1/1)

The title compound, [Hg3 (C6F4)3]·C6N4, contains one molecule of tetracyanoethylene B per one molecule of mercury macrocycle A, i.e., A•B, and crystallizes in the monoclinic space group C2/c. Macrocycle A and molecule B both occupy special positions on a twofold rotation axis and the inversion centre, respectively. The supramolecular unit [A•B] is built by the simultaneous coordination of one of the nitrile N atoms of B to the three mercury atoms of the macrocycle A. The Hg⋯N distances range from 2.990 (4) to 3.030 (4) Å and are very close to those observed in the related adducts of the macrocycle A with other nitrile derivatives. The molecule of B is almost perpendicular to the mean plane of the macrocycle A at the dihedral angle of 88.20 (5)°. The donor-acceptor Hg⋯N interactions do not affect the C=N bond lengths [1.136 (6) and 1.140 (6) Å]. The trans nitrile group of B coordinates to another macrocycle A, forming an infinite mixed-stack [A•B]∞ architecture toward [101]. The remaining N atoms of two nitrile groups of B are not engaged in any donor-acceptor interactions. In the crystal, the mixed stacks are held together by intermolecular C - F⋯C=N secondary interactions [2.846 (5)-2.925 (5) Å].