Tetrakis(1,3,4,6,7,9-hexaaza-1H-phenalen-6-ium) sodium(I) pentakis(tetrafluoridoborate)

In the title compound, Na+·4C7H5N6 +·5BF4 −, the Na+ ion lies on a fourfold rotation axis and one of the tetrafluoridoborate ions lies on a site of symmetry . Each Na+ ion is surrounded by four symmetry-related tetrafluoridoborate ions, and is eight-coordinated by F atoms, the Na⋯F separation being 2.3956 (15) or 2.4347 (17) Å. The hexaazaphenalenium ring system is essentially planar. In the crystal structure, the cations and anions are linked into a three-dimensional network by N—H⋯N and C—H⋯F hydrogen bonds.

In the title compound, Na + Á4C 7 H 5 N 6 + Á5BF 4 À , the Na + ion lies on a fourfold rotation axis and one of the tetrafluoridoborate ions lies on a site of symmetry 4. Each Na + ion is surrounded by four symmetry-related tetrafluoridoborate ions, and is eight-coordinated by F atoms, the NaÁ Á ÁF separation being 2.3956 (15) or 2.4347 (17) Å . The hexaazaphenalenium ring system is essentially planar. In the crystal structure, the cations and anions are linked into a three-dimensional network by N-HÁ Á ÁN and C-HÁ Á ÁF hydrogen bonds.
Because of the directionality of lone-pair electrons at the nitrogen sites, incorporation of nitrogen atoms into the phenalenyl skeleton was found to give substantial effects on its electronic structure. Suzuki et al. have reported the preparation and single cystal structure of the anion of hexaazaphenalene. Herein, we report the preparation and crystal structure of a hexaazaphenalene fluoroboric salt, the title compound.
In the title compound, the Na + ion lies on a four-fold rotation axis and one of the tetrafluoridoborate ions lies on a 4 site symmetry. One of the remaining four BF 4 ions and one of the four hexaazaphenalenium ions are symmetry independent, and they lie on general positions. Each Na + ion is surrounded by four symmetry related tetrafluoridoborate ions, with the Na···F separation being 2.3956 (15) or 2.4347 (17) Å (Fig.1). The hexaazaphenalenium ring system is essentially planar, with a maximum deviation of 0.042 (2) Å for atom N6. The C-N distances lie in the range 1.310 (3)-1.363 (3) Å.
Two types of hydrogen bonds viz. N-H···N and C-H···F exist in the solid state of the title compound. These hydrogen bonds link the cationic and anionic units into a three-dimensional network (Fig. 2). There are no face to face π-π staking involving the hexaazaphenalenium units, which is a common packing mode in other phenalene compounds.

Experimental
The sodium salt of hexaazaphenalene was prepared according to the literature method (Suzuki et al., 2005). To a water (5 ml) solution of sodium salt of hexaazaphenalene (97 mg, 0.5 mmol) was added 40% HBF 4 (0.5 ml, 3.0 mmol). The reaction mixture was evaporated slowly for 7 d to afford colourless crystals of the title compound.

Refinement
H atoms were initially located in difference maps and then refined using the riding-model approximation, with C-H = 0.95 Å, N-H = 0.88 Å and U iso (H) = 1.2U eq (C,N).