1-(2-Fluorobenzyl)quinolinium bis(2-sulfanylidene-1,3-dithiole-4,5-dithiolato-κ2 S,S′)nickelate(III)

The crystal structure of the title compound, (C16H13FN)[Ni(C3S5)2], consists of NiIII complex anions and 1-(2-fluorobenzyl)quinolinium (fbq) cations. In the complex anion, the NiIII cation is chelated by two 2-sulfanylidene-1,3-dithiole-4,5-dithiolate (dmit) dianions in a distorted square-planar geometry; the two dmit mean planes are twisted with respect to each other at a dihedral angle of 8.44 (3)°. In the fbq cation, the dihedral angle between the benzene ring and the quinoline ring system is 80.57 (14)°. The centroid–centroid distance of 3.860 (5) Å between benzene rings indicates π–π stacking between adjacent fbq cations. The distance of 3.4958 (18) Å between the S atom and the centroid of the pyridine ring suggests the existence of a lone-pair–aromatic interaction between the anion and the cation. A short S⋯S contact [3.387 (2) Å] is also observed in the crystal structure.


S1. Comment
The bis(dithiolate)-metal complexes and their analogues with interesting structures and/or potential applications such as conducting/magnetic or non-linear optical (NLO) materials have been reported in recent years (Cassoux, 1999). We report herein the crystal structure of the title bis-dithiolate-metal complex.
In this compound, the Ni II cations of NiCl 2 .6H 2 O have been oxidized to Ni III cation by I 2 (Cassoux et al., 1991), the Ni III cation is coordinated with two dmit II anions. As shown in Fig. 1, the asymmetric unit of the title compound contains one [Ni III (dmit) 2 ]anion and one [Fbzql] + cation. Each Ni III ion is coordinated by four S atoms from two dmit ligands to complete a square-planar geometry, with Ni-S bond lengths ranging from 2.1502 (14)  Two [Fbzql] + cations are associated together through face-to-face π···π interactions between two phenyl rings from different 2-fluorobenzyl groups (inter-centeriod distance: 3.8501 (9) Å) to form a bi-molecular unit, which expended to a one-dimensional structure running along the c-axis through another π···π interaction involving adjacent quinoline groups from different bi-molecular units with the shortest interface distance of 3.407 (4) Å.
The voids of the three-dimensional anion supramolecular structure are filled with the cation chains, as shown in and sodium (92 mg, 4.0 mmol) was added under a nitrogen atmosphere at room temperature to give a bright-red solution.
NiCl 2 .6H 2 O (238 mg, 1 mmol) was then added, followed successively by I 2 (127 mg, 0.5 mmol) and a solution of N-(2fluorobenzyl)quinolinium chloride (274 mg, 1 mmol) in methanol at an interval of approximately 20 min. The solution was stirred for a further 30 min and the resulting solid collected by filtration. Single crystals of the title compound were obtained by evaporation of a dilute acetone solution over two weeks at room temperature.

S3. Refinement
H atoms were positioned geometrically and refined using a riding model, with C-H = 0.93-0.97 Å and U iso (H) = 1.2U eq (C).

Figure 1
The cation and anion in [Fbzql][Ni(dmit) 2 ], showing the atom-labelling scheme, with thermal ellipsoids drawn at the 50% probability level. Hydrogen atoms have been omitted for clarity.   Refinement. Refinement of F 2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F 2 , conventional R-factors R are based on F, with F set to zero for negative F 2 . The threshold expression of F 2 > σ(F 2 ) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F 2 are statistically about twice as large as those based on F, and R-factors based on ALL data will be even larger.