L,3-DITHIOLE-2-THIONE-4,5-DITHIOLATE SALTS

Attempts to follow a published procedure for the preparation of l,3-dithiole-2-thione-4,5-dithiolate salts [1], involving reductive coupling of carbon disulfide with alkali metals, have led to violent explosions with potassium metal, but not with sodium [2]. However, mixtures of carbon disulfide with potassium—sodium alloy, potassium, sodium, or lithium are capable of detonation by shock, though not by heating. The explosive power decreases in the order given above, and the first mixture is more shock-sensitive than mercury fulminate [3]. 

Tetrathiafulvalenes can be prepared in a number of ways, for example via l,3-dithiole-2-thione-4,5-dithiolate - the simple salts of this dianion are not very stable, but can be stored as a zinc complex, or as the dithiobenzoate shown below. 

Kusamoto T, Yamamoto HM, Tajima N, Oshima Y, Yamashita S, Kato R (2012) Bilayer Mott system based on Ni(dmit)2 (dmit =l,3-dithiole-2-thione-4,5-dithiolate) anion radicals two isostructural salts exhibit contrasting magnetic behavior. Inorg Chem 51 11645-11654... 

Supramolecular compounds are formed by treatment of silver salts and the ligand 4,5-ethyle-nedithio-l,3-dithiole-2-thione (C5H4S5), such as the polymeric chain [ AgfCd [4S5)3 Cl04-MeCN]2 or the 2D [Ag(C5H4S5)OTf]ra. All are assembled by S "S contacts.1 5... 

Bulk crystalline radical ion salts and electron donor-electron acceptor charge transfer complexes have been shown to have room temperature d.c. conductivities up to 500 Scm-1 [457, 720, 721]. Tetrathiafiilvalene (TTF), tetraselenoful-valene (TST), and bis-ethyldithiotetrathiafulvalene (BEDT-TTF) have been the most commonly used electron donors, while tetracyano p-quinodimethane (TCNQ) and nickel 4,5-dimercapto-l,3-dithiol-2-thione Ni(dmit)2 have been the most commonly utilized electron acceptors (see Table 8). Metallic behavior in charge transfer complexes is believed to originate in the facile electron movements in the partially filled bands and in the interaction of the electrons with the vibrations of the atomic lattice (phonons). Lowering the temperature causes fewer lattice vibrations and increases the intermolecular orbital overlap and, hence, the conductivity. The good correlation obtained between the position of the maximum of the charge transfer absorption band (proportional to... 

Photochemical rearrangement of some mesoionic 1,3-dithioles (160) and (161) produces the dithioles (162) and (163) (80CA(92)19766l), and 4,5-dimercapto-l,3-dithiole-3-thione (164) salts are reported to rearrange to 4,5-dimercapto-l,2-dithiole-3-thione (165) salts (77EGP124044). 

Thione groups can often be eliminated by oxidation probably the sulfinic acid is the intermediate. Sometimes the sulfinic acid can be isolated (e.g., 740 741), but more often it spontaneously loses SO2. In this way, thiazoline-2-thiones give thiazoles, l,2-dithiole-3-thiones 742 are converted into 1,2-dithiolylium salts 743, l,3-dithiole-2-thiones 744 into 1,3-dithiolylium salts 745, 1,5-disubstituted imidazole-2-thiones into imidazoles <2003JHC229>, and 3-mercapto-l,2,4-triazoles into the parent triazole <2006S156>. In the pyrazole series, 746 also loses an A-methyl group to yield 747. 

Similar examinations of the CT spectra for bis(propylenedithio)-tetrathiafulvalene (BPDT-TTF) salts [36], BEDT-TTF salts [37], and bis-tetramethylenetetraselenafulvalene-(4,5-dimercapto-l,3-dithiole-2-thione)nickel [OMTSF-Ni(DMIT)2] salt [38] have been performed. The latter salts are examples of organic conductors that are almost isotropic in two dimensions. Thus only weak polarization dependence is found in the entire frequency range. The analysis of the spectra within a simple DA-charge oscillator model, which takes into account the coupling to intramolecular vibrational modes, demonstrates how IR and optical measurements can provide estimates for a number of physical parameters for lowdimensional organic conductors. 

Furthermore, superconductivity has been found in some salts based on the acceptor molecule M(dmit)2, where M = Ni, Pd, or Pt and dmit is 4,5-dimercapto-l,3-dithiole-2-thione (= C3S5) [22, 23]. 

Reaction of 4-fluoro5-5-(l,l,2,2-tetrafluoroethyl)-3//-dithiole-3-thione with 2equiv of Na2S affords 3,4-difluoro-2-mercapto-l,6,6aA-trithiapentalene after an acidic work-up. Further reduction with Na2S gives 3,5-difluoro-4-mercapto-2//-thiopyran-2-thione 507 in >30% overall yield. Methylation of the Na salt of the pentalene affords an 1 1 mixture of methylsulfanyl derivatives of a 2//-thiopyran-2-thione 508 and 4//-thiopyran-4-thione 509 (Scheme 190). DFT calculations predict the stability sequence for the thiones is 507 > 508 > 509 <2006JFC(127)774>. 

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