4,4′,5,5′-Tetrakis(benzylsulfanyl)tetrathiafulvalene

The asymmetric unit of the title compound, C34H28S8, contains two crystallographically independent half-molecules. The molecules lie on centers of inversion. The four benzene rings of each molecule are substantially twisted from the planes of the 1,3-dithiole rings, forming dihedral angles of 43.6 (2) and 61.4 (1)° in one molecule and 54.2 (1) and 65.2 (1)° in the other.

The asymmetric unit of the title compound, C 34 H 28 S 8 , contains two crystallographically independent half-molecules. The molecules lie on centers of inversion. The four benzene rings of each molecule are substantially twisted from the planes of the 1,3-dithiole rings, forming dihedral angles of 43.6 (2) and 61.4 (1) in one molecule and 54.2 (1) and 65.2 (1) in the other.

Experimental
The asymmetric unit of the title compound, C 34 H 28 S 8 , contains two crystallographically independent half-molecules.
The molecules lie on centers of inversion. They adopt chair-like conformations and the four benzene rings of each molecule are severely twisted from the planarity of the 1,3-dithiole rings (Fig. 1). Due to the C i symmetry of the molecules, the substituent groups of the TTF core are located in opposite directions, resulting in chair-like molecular conformations. The four benzene rings of each molecule are severely twisted from the planarity of the 1,3-dithiole rings. The C-S bonds in the five-membered rings fall in the range of 1.742 (4)-1.761 (4) Å and are shorter than a typical C-S single bond (1.82 Å; Allen et al., 1987), revealing the high degree of conjugation into the five-membered rings of the title compound. On the other hand, the S-C(CH 2 Ph) bond distances are longer than the C-S bonds of the rings falling in the range of 1.794 (5)-1.837 (5) Å, similar to a typical C-S single bond. The mean planes of the C5-C10 and C12-C13 benzene rings [C22-C27 and C29-C34] form dihedral angles of 43.6 (2) and 61.4 (1)° [54.2 (1) and 65.2 (1)°] with the least-squares plane of the central dithiolane ring, respectively. The crystal packing diagram of the title compound is shown in Fig. 2. The shortest intermolecular S-S distances, S(1)-S(2) and S(5)-S(6) distances, are 3.793 (2) Å and 3.855 (2) Å, respectively.

Experimental
A total of 42.15 mg (0.3 mmol) of K 2 CO 3 was dissolved in less than 5 ml of water, and 100 mg (0.61 mmol) of 3-picolyl chloride hydrochloride was added at room temperature. After the gas evolution was stopped, a colorless dense liquid was present. Subsequently, 143.35 mg (0.15 mmol) of TBA2[Zn(DMIT)2] dissolved in 15 ml of acetonitrile was mixed with this dense liquid, and the solution was stirred at 50-60 °C for 1.5-2 h. The reaction mixture was filtered, and the solid residue was washed twice with dichloromethane (20 ml). The combined filtrate and washings were decolorized by activated charcoal. After removing the solvent, column chromatography of the crude reaction mixture on silica gel with ethyl acetate/ methanol (10:1) afforded compound 1a as a yellow solid (85.5 mg, 75%). Benzyl chloride (12 ml) was added dropwise to a solution of TBA2[Zn(DMIT)2] (10 mmol) in acetone (100 ml). The mixture was refluxed under N 2 for 24 h. Stirring was continued overnight. The resulting orange precipitate was filtered off. The product was further purified by recrystallization from methanol to give yellow needle like crystals (yield 76%). All solvent were distilled before use. 95 mg (0.25 mmol) of 4,5-bis(3-picolylthio)-1,3-dithiole-2-thione and 144 mg (0.4 mmol) of 4,5-bis(benzylthio)-1,3-dithione-2-thione (0.3 mmol) were stirred in 30 ml of dry toluene under N 2 . Then, 2.5 ml of P(OEt) 3 was added and the yellowish suspension was refluxed for 4 h at 120 °C. The resulting orange yellow precipitate that formed was filtered off. The red filtrate was left to stand for several days, giving pale red crystals suitable for a X-ray structure analysis.
supplementary materials sup-2 Refinement All non-hydrogen atoms were located from the difference Fourier maps, and were refined anisotropically. All H atoms were positioned geometrically, and were allowed to ride on their corresponding parent atoms with U iso = 1.2 U eq . Fig. 1. The molecular structure of the title compound with 30% probability ellipsoids.