Preparation of organic polysulfanes R2Sn (n=5, 7, 8, 9) from sulfenyl chlorides, RSCl, and transition metal polysulfido complexes

The preparation of seven novel organic polysulfanes is reported. Bis(n-octy l)heptasulfane R2S7 1 is formed upon reaction of RSCl with [Cp2TiS5], while the corresponding nonasulfane R2S9 2 is Obtained by reaction of RSSCl with [Cp2TiS5]. The bis(n-octyl)pentasulfane R2S5 3 is obtained from RSCl and [ (Cp'2TiCl)(2)S-3] by transfer of the S-3 ligand at 20 degrees C. The new al kyl polysulfanes 1-3 have been obtained in quantitative yields. They are li quids at 20 degrees C, having freezing points below -50 degrees C, but do n ot form mesogenic phases. Reactions of [Cp2TiS5] with 2-naphthyl- and 4-chl orophenyl sulfenyl chloride furnish the corresponding heptasulfanes 4 and 5 , respectively, which are solids at 20 degrees C. 1,2-Benzodisulfenyl chlor ide C6H4(SCl)(2) reacts with [(Cp'2TiCl)(2)S-3] to give the known 1,2,3,4,5 -benzopentathiepin C6H4S5 6, with [CP2TiS5] to give the novel 1,2,3,4,5,6,7 -benzoheptathionin C6H4S7 7, and with [(TMEDA)ZnS6] to give the novel 1,2,3 ,4,5,6,7,8-benzooctathiecin C6H4S8 8. The cyclic polysulfanes 6-8 are solid s at 20 degrees C and have been recovered in yields of 60-83%. The orthorho mbic structure of 1,2-C6H4S7 has been investigated by single-crystal X-ray diffraction analysis. The molecules are found to be located at sites of C-s symmetry and the motif of the C2S7 heterocycle is +-+-+-+-, with the torsi on angle of zero at the carbon-carbon bond. The three internuclear SS dista nces measure 205.0(1), 203.7(1), and 205.7(1) pm.