Macrocyclic polysulfides

Although the polysulfur macrocycles became more interesting to the scientific community after Pedersen s report of the crown compounds (see Chap. 1), examples of such structures may be found in the literature dating back some time. The first report of a macrocyclic polysulfide appears to be that by Ray who found in 1920 that when 1,2-dimercaptoethane and 1,2-dibromoethane were heated with alcoholic potassium hydrogen sulfide as shown in Eq. (6.2), triethylene trisulfide (2) and a substance presumed to be triethylene tetrasulfide (3) could be isolated. 

A reaction of dithiadiazocanes 234 with sulfur monochloride gave a novel macrocyclic polysulfide, 1,2,3,5,7-pentathiocanes 235, in moderate-to-high yields (2002CL90). The NMR monitoring of this reaction suggested that a plausible route involved the formation of an oxidative transannular S-S bond in a thermally stable secondary species, a symmetrical dithiadication 236, followed by... 

Polysulfanides, in Ru and Os half-sandwich complexes, 5-Gp and 7 5-indenyl compounds, 6, 496 Polysulfide rings, with germanium, 3, 742-743 Polysulfides, in Ru and Os half-sandwich complexes, rjS-Cp and ]5-indenyl compounds, 6, 496 Polysulfido nitrosyl complexes, with chromium, 5, 303 Polytetrafluoroethylene valves, in high vacuum lines, 1, 198 Polythiaether macrocyclic ligands, in hexaruthenium carbido clusters, 6, 1018-1019... 

Besides thiolate, RSe and RTe complexes, there are also HgX2(ER2) complexes, which generally dimerize to give approximately tetrahedral Hg.82 There are also numerous complexes of Hgn with macrocyclic ligands of sulfur83 as well as a number of polysulfide complexes, such as [Hg(S6)2]2 formed on addition of S2 to Hg11 acetate in methanol. Polytelluride complexes have recently been characterized.84... 

First, the sulfur atom from a thiirane is added to one of the carbon atoms of the thiirane ligand of the complex, with formation of a zwitterionic intermediate. The zwitterionic intermediate undergoes elimination of ethylene to yield a reactive alkene disulfide tungsten complex. The dithietane ligands from two or more molecules, then combine to form the cyclic polysulfides. If the macrocyclization of thiirane catalyzed by W(CO)s(SC2H4) is performed in the presence of DMAD, small quantities of polythioether macrocycles 156 and 157 are formed <1997OM1430>. 

An FAB-MS study on several aromahc, aliphatic, and aliphatic-aromatic polysulfides doped with heavy metal salts allowed the detection of adducts of the cyclic sulfides with heavy metal ions Ag, Hg, and Cu - The molecular ions of the cyclic sulfides and those corresponding to the metal adducts appeared in the spectra with widely differing intensities, providing a tool to investigate the selectivity of metals toward macrocyclic sulfides of different structure and size. ... 

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