1.3- Dithioles, 2- preparation, structure

The palladium-catalyzed formation of sulfides can generate polyphenylene sulfide from a dithiol and a dibromoarene, or from 4-bromobenzenethiol (Equation (38)).17 In 1984 Asahi Glass obtained patents for the formation of this polymer in the presence of palladium and nickel catalysts.125,126 In addition, Gingras reported palladium-catalyzed couplings of aryl halides and thiols to form discrete phenylene sulfide oligomers.127,128 A number of polyphenylene sulfide wires, ranging from dimeric to pentameric structures, were prepared by the palladium coupling, albeit in modest yields ... 

Elimination of hydrogen halides from dihalogenoorganylboranes by reaction with ferrocene-1,1 -dithiol resulted in l,3-dithia-2-boryl[3]ferrocenophanes.170 These borylferrocenophanes were air sensitive, but were characterized by NMR, MS, and elemental analysis.170 A series of l,3-dibora-2-X-[3]fer-rocenophanes (X=S, Se, Te) were prepared and characterized and the crystal structure of [Se N Pr2)BC5Fl4 2Fe] has been reported.171... 

Over the past decade a number of new covalently bonded TTF/ferrocene adducts have been reported [77, 78]. The crystal structure of the l,l -bis(l,3-dithiole-2-ylidine)-substituted ferrocene derivative has been published [77]. In this complex, ferrocene has essentially been incorporated as a molecular spacer between the two l,3-dithole-2-ylidene rings forming a stretched TTF molecule. This adduct, and its methyl-substituted derivative, have been combined with TCNQ to form charge-transfer complexes with room temperature powder conductivities of 0.2 S cm-1. Similar diferrocenyl complexes have been prepared with bis (dithiolene) metal complexes [79, 80]. 

The synthesis of Au(ppy)(CxH4Sg) and Au(ppy)(C 10-C6SX), including the crystal structure of the former, have been reported [97]. The triiodide and TCNQ salts of both complexes have also been prepared by chemical oxidation. Analysis of the EPR spectra indicates that the oxidation is centered on the dithiolate ligands. High room temperature conductivities of 2-4 x 10-2 S cm-1 were measured on compacted polycrystalline samples for the oxidized complexes. 

The synthesis, X-ray structure and solid state NMR of 4,4-dimethyl-l,2-ditellurolane 75 have been reported <98PS(136-8)291>. Chemoselective oxidation of 1,2-dithiole derivatives using dimethyldioxirane to give products such as 76 has been described <00SUL169>. Cycloaddition of dihydroquinoline-fused l,2-dithiole-3-thiones 77 with DMAD gives the spiro 1,3-dithioles 78 <99CHE587>. Dicationic thiatelluroles such as 79 have been prepared <00AG(E)1318>, anti cancer properties have been claimed for the simple dithiolopyrrolones... 

Some miscellaneous examples of QD synthesis using surfactant systems are described below. A layer-by-layer [206] structure of dithiol self-assembled monolayers (SAM) and CdS mono- and multilayer nanoparticles were fabricated on a gold substrate covered with alkanedithiol. SAMs were formed by an alternate immersion of the substrate into ethanolic solutions of dithiol, and dispersion of CdS nanoparticles (ca. 3nm in diameter), the latter of which was prepared in A0T/H20/heptane w/o microemulsions. 

A second important class of complexes contains both thiolate and tertiary phosphine ligands. These are prepared by reactions such as those of equations (28) or (29).187,228,233-236 Bridged complexes (9) and (10) may be prepared either from dithiols or from tertiary phosphine thiol derivatives, respectively.187,237 The structure of the large ring complex (10) has been determined.238... 

Dithiols give several stable square planar gold(III) complexes. Some complexes of biochemical interest are those derived from 2,3-dimercaptopropanol (BAL),230 dimercaptosuc-cinic acid249 and penicillamine.542 These are thought to have structures similar to that of the toluenedithiolate derivative (72).543 They can be prepared by reaction of [AuCLJ- with the dithiol and base or by oxidation of gold in the presence of the dithiol. 

Bridged structure 169 containing two dithiazepane rings was readily prepared from diketopiperazines 167 and gent-dithiols under mild conditions <1981JHC1545>. 

Synthesis of 1,3,2-dithiazoles has been the most extensively studied. Various structural types of these compounds have been synthesized in 1990s from raV-dithiols, bis(sulfenylchlorides), and alkynes <1996CHEC-II(4)433>. Much attention has been paid to the preparation of stable 1,3,2-dithiazolyl radicals and, especially, cations. The synthetic potential of 1,3,2-oxathiazoles and 1,3,2-dioxazoles is restricted by several uncommon procedures including nitrosation of thiolcarboxylic acids and photochemical addition of nitrobenzene to alkenes <1996CHEC-II(4)433>. 

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