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We have reported a series of [Ni(dmit)2]– complex salts,1,2 and recently found a new type of crystal structure in benzyldimethyl(ω-phenylalkyl)ammonium salts (BnCnPh; n = 1 – 4).3 Most of the crystal structures of [Ni(dmit)2]– were classified as a “Segregated stack” or a “Alternant stack” in which anions and cations are piled up separately or alternately, but the BnCnPh series had both characteristics.4,5 In this work, we changed terminal group from phenyl to cyclohexyl, so as to compare the effect of the aromatic group (phenyl) with the aliphatic group (cyclohexyl). Among the research, we found another type of crystal structure shown in Fig. 1. Usually, [Ni(dmit)2]– anions form a parallelly piled dimer, but we find in this crystal, a one-dimensional anion network in which the anions are arranged vertically to each other. Furthermore, the [Ni(dmit)2]– anion plane is found to be significantly bent.

The synthesis of benzyldimethyl(ω-cyclohexylethyl)-ammonium bromide: N,N-dimethylbenzylamine (2 mmol) and (2-bromoethyl)cyclohexane (2 mmol) were stirred in acetonitrile (20 mL) for 48 h. Acetonitrile was then removed by evaporation to obtain a crude white product.

The synthesis of (BnC2cHx)[Ni(dmit)2] complex salt (BnC2cHx = benzyldimethyl(ω-cyclohexylethyl)ammonium): 4,5-di(thiobenzoyl)-1,3-dithiole-2-thione (dmit(COPh)2) was synthesized by a reported method.6 The obtained dmit(COPh)2 (0.50 mmol, 202 mg) was treated with an excess of sodium

methoxide in methanol (20 mL) under nitrogen at room temperature with stirring. To the resulting dark-red solution, Ni(CH3COO)2·4H2O (0.25 mmol, 62 mg) in methanol (10 mL) and benzyldimethyl(ω-cyclohexylethyl)ammonium (BnC2cHx) bromide (0.50 mmol) in methanol (10 mL) were added successively. The precipitates formed were washed with methanol. Complex salt was obtained by oxidizing these precipitates in acetone using I2 (1 mmol, 127 mg) and NaI

2017 © The Japan Society for Analytical Chemistry

† To whom correspondence should be addressed.E-mail: B116703@ed.tus.ac.jp (S. K.); miyamura@rs.kagu.tus.ac.jp (K. M.)

Crystal Structure of Benzyldimethyl(ω-cyclohexylethyl)ammonium Bis(2-thioxo-1,3-dithiole-4,5-dithiolato)nickelate(III)

Shunta KAKIHARA,*† Masahiro SAEKI,* Shuhei ICHIMURA,* Yoshinori TAMAKI,** and Kazuo MIYAMURA*†

* Department of Chemical Science and Technology, Graduate School of Chemical Science and Technology, Tokyo University of Science, 1-3 Kagurazaka, Shinjuku, Tokyo 162–8601, Japan

** School of Dentistry, Faculty of Dentistry, Meikai University, 1-1 Keyakidai, Sakado, Saitama 350–0283, Japan

The crystal structure of the title compound, (C17H28N)[Ni(dmit)2] (dmit = 2-thioxo-1,3-dithiole-4,5-dithiolato, C3S52–) is

characterized by its unusually bent molecular structure in which two ligands, C3S52– in [Ni(dmit)2]–, have a gradient of

19.01(6)° to one another, and [Ni(dmit)2]– anions are found to form a one-dimensional network in the direction of the a axis by intermolecular S–S contacts between the adjoining anions located almost vertically. Among these vertically arranged anions, the dihedral angle between the adjacent planes of the anions (S–S–Ni–S–S) is 69.51(2)°.

(Received November 15, 2016; Accepted December 19, 2016; Published on web March 10, 2017)

Fig. 1　Chemical diagram of the title compound.

Table 1　Crystal and experimental data

Chemical formula: C23H28NNiS10

Formula weight = 697.77T = 173 KCrystal system: orthorhombic Space group: P212121

a = 7.9129(11)Åb = 17.270(3)Åc = 21.673(3)ÅV = 2961.8(7)Å3 Z = 4Dx = 1.565 g/cm3

Radiation: Mo Kα (λ = 0.71073 Å)μ(Mo Kα) = 1.376 mm–1 F(0 0 0) = 1444Crystal size = 0.40 × 0.08 × 0.07 mm3

No. of reflections collected = 18100No. of independent reflections = 6708θ range for data collection: 1.508 to 28.258°Data/Restraints/Parameters = 6708/0/318Flack parameter = 0.024(17)Goodness-of-fit on F2 = 0.821R indices [I > 2σ(I)]: R1 = 0.0469, wR2 = 0.0641R indices (all data): R1 = 0.0802, wR2 = 0.0734(Δ/σ)max = 0.000(Δρ)max = 0.65 (Δρ)min = –0.47Measurement: Bruker SMART APEX CCD diffracrometerPrograms system: SHELXTL-2014Structure determination: SHELXS-97CCDC deposition number: 1515023

16 X-Ray Structure Analysis Online 2017, VOL. 33

(1.3 mmol, 195 mg) according to a literature procedure.6 The resultant black crystals were collected by filtration, and purified by recrystallization. Block-like single crystal of (BnC2cHx)[Ni(dmit)2] was grown by slow evaporation from an acetone and methanol mixed solution at room temperature. Elemental analysis for C23H28NNiS10: Calc: C, 39.59; H, 4.04; N, 2.01%. Found: C, 39.63; H, 3.90; N, 2.02%

Diffraction data were collected at 173 K with a Bruker AXS SMART diffractometer equipped with a CCD area detector. The structure was solved with SHELX-97 and refined with SHELXL-2014 using the direct method, and expanded using Fourier techniques. All non-hydrogen atoms were refined anisotropically by a full-matrix least-squares method, and hydrogen atoms were refined isotropically. A  summary of the crystallographic data and structure refinements is presented in Table 1.

An ORTEP view of the title compound is shown in Fig. 2. The selected bond lengths and angles are listed in Table 2. Usually, [Ni(dmit)2]– complexes form a parallelly stacked dimer in a crystal stabilized by π-π contacts. However, there are few exceptional examples of crystals containing vertically contacted dimers or trimers.7,8 The Ni–Ni distances in such crystals range from 3.501 – 8.613 Å. In the title crystal, the arrangement of the anions adopts a zig-zag one dimension network along the a  axis by S–S contacts (Fig. 3), and anion complexes are arranged in a vertical position to each other. The distances of Ni–Ni, S6–S4, S1–S2, and S3–S7 are 5.7512(12), 3.5370(22), 3.7917(20) and 3.6304(22)Å, respectively (Fig. 4), and the dihedral angle between two Ni1–S1–S2–S6–S7 planes is 69.51(2)°. The outstanding feature of this crystal is that the [Ni(dmit)2]– anion is bent by a dihedral angle between two dmit ligands of 19.01(6)° (Fig. 5). In most crystals of [Ni(dmit)2]– salts, the dihedral angle between two dmit ligands is small. We researched 437 cif data of the [Ni(dmit)2]– series, and only 18 data exhibited a bending structure with S–S contacts between

anions having the angle of two dmit ligands exceeding 10°. In these crystals, N–H···S or C–H···S contacts between cations and anions were found, and the most bent anions among them was 17.23°,9 smaller than the one we found.

References

1. Y. Soneta and K. Miyamura, Bull. Chem. Soc. Jpn., 2006, 79, 282.

2. K. Dai, S. Kusunoki, M. Hirota, K. Tomono, and K. Miyamura, X-ray Struct. Anal. Online, 2011, 27, 35.

3. M. Saeki, K. Dai, S. Ichimura, Y. Tamaki, K. Tomono, and K. Miyamura, Bull. Chem. Soc. Jpn., 2015, 88, 358.

4. Q. Ye, T. Akutagawa, N. Hoshino, T. Kikuchi, S. Noro, R.-G. Xiong, and T. Nakamura, Cryst. Growth Des., 2011, 11, 4175.

5. G.-Z. Yang, L. Yao, and X.-Y. Cui, Acta Cryst., 2006, E62, m2963.

6. G. Steimecke, R. Kirmse, and E. Hoyer, Z. Chem., 1975, 15, 28.

7. N. Hoshino, K. Kubo, T. Nakamura, and T. Akutagawa, Dalton Trans., 2012, 41, 9297.

8. T. Nakamura, A. E. Underhill, A. T. Coomber, R. H. Friend, H. Tajima, A. Kobayashi, and H. Kobayashi, Inorg. Chem., 1995, 34, 870.

9. D.-Q. Wang, J.-M. Dou, M.-J. Niu, D.-C. Li, and Y. Liu, Huaxue Xuebao, 2002, 60, 2145.

10. G. M. Sheldrick, Acta Cryst., 2015, C71, 3.11. G. M. Sheldrick, Acta Cryst., 2008, A64, 112.

Fig. 2　ORTEP drawing off the title compound with the atom numbering scheme. Displacement ellipsoids are drawn at the 50% probability level. H atoms have been omitted for clarity.

Fig. 4　S–S contacts between [Ni(dmit)2]. Symmetry code –1/2+x, 1/2–y, –z.

Fig. 3　One dimensional structure view.

Fig. 5　Dihedral angle between two dmit ligands.

Table 2　Selected bond lengths (Å) and angles (°)

Bond length Angle

Ni1–S1 2.1680(12) S1–Ni1–S2 93.14(5)Ni1–S2 2.1515(14) S6–Ni1–S7 93.11(5)Ni1–S6 2.1655(13) S1–Ni1–S7 177.86(6)Ni1–S7 2.1514(13) S2–Ni1–S6 176.64(5)

S2–Ni1–S7 84.74(5)S1–Ni1–S6 89.00(5)