Isomers among the carbon sulfides C₄S₆—synthesis and crystal structures of α,α-C₄S₆, α,β-C₄S₆, and of a second polymorph of the diiodine adduct α,β-C₄S₆·I₂

Abstract

The reaction of the alpha and beta forms of C3S5(2-) with thiophosgene yields two isomeric carbon sulfides alpha,alpha-C4S6 and alpha,beta-C4S6, respectively. The crystal structures of both compounds could be determined for the first time. Both structures are made up of almost planar molecules. The alpha,alpha-isomer (1,3-dithiolo-(4,5-d)-1,3-dithol-2,5-dithione) is D2h-symmetric, while the alpha,beta-isomer is approximately Cs-symmetric. In the molecules of both isomers the two different C3S5 units are retained without significant alterations of structural parameters. alpha,alpha-C4S6 is unstable with respect to alpha,beta-C4S6. The molecular rearrangement can be induced by a short thermal treatment at 150 degrees C. Significant differences are found in the mass spectra fragmentation patterns. Only alpha,beta-C4S6 shows an intense signal for C3S2+ and is therefore a potential source for the synthesis of carbon subsulfide via flash vacuum pyrolysis. Only alpha,beta-C4S6 forms a stable adduct with I2. alpha,beta-C4S6.I2 was already known (F. L. Lu, K. M. Keshavarz-K, G. Srdanov, R. H. Jacobson and F. Wudl, J. Org. Chem., 1989, 54, 2165, ), but a second polymorph is formed on crystallisation from a different solvent. The two polymorphic forms do not show differences in the structures of the individual molecules but show a different packing pattern. alpha,beta-C4S6.I2 is remarkably thermally stable. Thermal analysis shows that I2 cleavage occurs in that temperature region above 200 degrees C when C-S bonds are broken and CS2 and I2 are simultaneously liberated. Performed at 270 degrees C thermolysis of alpha,beta-C4S6.I2 yields under cleavage of I2 and CS2 a black polymeric carbon sulfide (CS)x which is probably a mixture of graphitic carbon and unidentified amorphous polymeric carbon sulfides.

Dithiolopyranthione Synthesis, Spectroscopy, and an Unusual Reactivity with DDQ

“…A search of the Cambridge Crystallographic Structure Database indicates that dithione 3b is the only example of such a bicyclic motif. The C═S double bond is significantly shorter (1.602(3) Å) than that reported in a related compound (1.657 Å) , whereas the C─S single bonds (1.790(6) Å, 1.730(4) Å) are close to those reported for similar thiones . The six membered pyran ring adopts a typical " chair" conformation, the [1,3]‐dithiolo‐2‐thione fragment is essentially planar, whereas the five‐membered C1–S2a–C2a–C3a–S3a heterocyclic moiety adopts a twist conformation.…”

Two-dimensional polymeric [Hg4(μ2-I)6I2(μ2-C4S6)]n

“…(1.671 (10) Å versus 1.645 (2) in the free ligand, Beck et al, 2006). The Hg1-S2 distance of 2.697 (3) Å is somewhat longer than that reported for 4,5-bis(methylthio)-1,3-dithiole-2-thione on HgI 2 (Hameau et al, 2006).…”

“…For the synthesis and structure of the ,-C 4 S 6 ligand, see: Krug et al (1977); Beck et al (2006). For related studies on polymeric binary carbon sulfides, see: Galloway et al (1994).…”

“…The α,α-C 4 S 6 ligand was prepared as described previously (Beck et al, 2006). To the α,α-C 4 S 6 dithione (14 mg, 58 µmol) dissolved in 13.5 ml of a solvent mixture (toluene/acetonitrile/chlorobenzene in 2/1/1 ratio) was added upon stirring a solution of HgI 2 (53 mg, 116 µmol) in toluene (10 ml).…”

Halogen Bonding with Dihalogens and Interhalogens

“…Since then, a large number of such complexes have been studied. This interest has been driven in large part by research in two areas: the unusual electric properties imparted to materials when doped with dihalogens (particularly iodine) [55], and the study of dihalogen and interhalogen complexes with potential antithyroid drugs and related derivatives, including dithiole thiones [56][57][58][59][60][61][62][63][64][65], imidazole thiones [19,[66][67][68][69][70][71][72][73] and selones [68,[74][75][76], thiazole thiones [77] and selones [78][79][80], oxazole thiones [81], and various thiourea derivatives [77,82]. Additional activity has involved the fundamental study of halogen bonding in particular classes of compounds, such as aromatic nitrogen heterocycles [31,[83][84][85][86][87][88][89][90][91][92][93][94]96], thioether...…”