Dithiocyanates

Other Inorganic Compounds. Alkali—metal and ammonium teUuropentathionates (Te(S203)2), have been prepared. The S2O3 group can be replaced by ethyl xanthate or diethyl dithiocyanate. 

Tellurium pseudohaUdes, such as the dicyanide [14453-24-8] Te(CN)2, the dithiocyanate [83543-04-8] Te(SCN)2, and thiourea complexes with Te(SCN)2, have been prepared. These are similar to the haUdes in properties. 

The trarax-dichloro and dithiocyanate complexes show MLCT transitions in the entire visible and near IR region. The lowest energy MLCT transition band of the trara-dichloro complexes is around 700 nm in DMF solution, and the complexes show weak and broad emission signals above 950 nm. The absorption and emission maxima of the Zrarax-dithiocyanate complexes are blue shifted compared to its trarax-dichloro analogues due to the strong -k acceptor property of the NCS- ligands compared to Cl-, which is consistent with the electrochemical properties of these complexes. 

Diaminopyridine undergoes 3-thiocyanation and 3,5-dithiocyanation (equation 57) (62JCS3464). 6-Substituted 3-aminopyridines react under similar conditions at C-2 and the... 

An Oceanapia sp. collected off the northern Rottnest Shelf, Australia, has yielded three novel dithiocyanates, thiocyanatins A-C (623-625). The structures were determined by spectroscopic analysis and confirmed by total synthesis. The thiocyanatins contain an unprecedented dithiocyanate functionality and an unusual 1,16-difunctionalised n-hexadecane carbon skeleton. They possess nematocidal activity [496]. 

The group VIB cyanides, thiocyanates and selenocyanates and their complexes with species such as thiourea have been described.1,45 For example, the tellurium dithiocyanate complex has been prepared45 by treatment of tellurium dichloride or tellurium dibromide with ammonium thiocyanate. It seems that little information exists on the preparation of tellurocyanates and there is a sparsity of data on polonium derivatives. Indeed, the only known cyanide of polonium is probably a salt of the quadrivalent element.1... 

Disulphur Dithiocyanate, S (SCN)2, is formed 3 by the interaction of sulphur chloride and a metalliclthiocyanate, the best and most uniform results being obtained when mercuric thiocyanate is used. Chloroform or carbon tetrachloride forms a suitable solvent if the product is only required in solution, since these do not dissolve mercury salts if the compound is to be isolated, carbon disulphide is the required solvent. Disulphur dithiocyanate forms colourless crystals which melt at —3-3° C., forming a viscous, yellow, odourless liquid, which is somewhat unstable. On cautious heating it becomes dark yellow, then red, and finally detonates. It is hydrolysed by water according to the equations ... 

Ferric thiocyanate is readily soluble in aqueous ether, and the extract possesses a deep violet colour which can be completely discharged by the addition of ferric chloride. The explanation of this effect put forward by Clarens3 is that an excess of thiocyanate is necessary for the formation of ferric thiocyanate when a ferric salt is added this excess of thiocyanate is removed and a salt of dithiocyanic acid, insoluble in ether, is formed.4... 

Dithiocyanic Acid, (HGNS)2, is obtained by decomposing its potassium salt with sulphuric acid. The potassium salt is formed when perthioeyanic acid (see below) is treated with a cold aqueous solution of potassium hydroxide.7 It is a dark yellow powder, slightly soluble in cold water, more soluble in hot water it is soluble in alcohol and in ammonia. Aqueous and alcoholic solutions made in the cold do not colour ferric salts.8... 

Chattaway and Stevens, Trans. (Them. 80c., 1897, 71, 607. For various reduction products of perthioeyanic acid, see Chattaway and Stevens, ibid., p. 833. For the constitution of dithiocyanic and perthioeyanic acids, see Hantzsch and Wolvekamp, Annalen, 1904, 331, 265. 

Makosza and Fedorynski60 have also shown that carbanions react with organic thiocyanates by displacing CN e.g., phenylacetonitrile and 1,2-ethylene dithiocyanate (32) give 1,3-dithiolane (33). 

Cyclohexene sulfide,7 S-eyolohexylethylcne sulfide,7 and letra methykthykne sulfide12 are reported to be formed in poor yields from the corresponding dithiocyanates. 

Exposure of alkenes to a combination of 4 and trimethylsilyl isothiocyanate leads to the formation of 1,2-dithiocyanates [Eq. (8)] [28]. The reaction involves the formation of bis(thiocyanato)-A3-iodane by a ligand exchange. The decomposition of this iodane leads to the formation of thiocyanogen, which in turn undergoes the anti electrophilic addition to olefins. 

Dithiocyanations with the related system, BAIB/KSCN (1 2, MeCN), are restricted to activated substrates such as dihydropyran and a-methylstyrene,... 

The treatment of alkynes with the combined reagent, PhICl2/Pb(SCN)2, in dichloromethane at 0-5°C provides access to frans-bis(thiocyanato)alkenes [58]. Whether thiocyanogen, thiocyanogen chloride, or [bis(thiocyanato)-iodo]benzene is responsible for dithiocyanation of the C,C-triple bond has not been established. 

The trans-dichloro and dithiocyanate complexes 21-24 show MLCT transitions in the entire visible and near IR region. The lowest energy MLCT transition band of the frans-dichloro complexes 21 is around 700 nm in DMF... 

The propensity of the thiocyanate ion for alkynylation with alkynyliodonium ions has also been demonstrated with a series of bis(phenyliodonium)diyne triflates (equations 61 and 62)43. The efficient production of diynediyl dithiocyanates in these reactions may be contrasted with the favored formation of mono- and bis-cyclopentenyl sulfones from bisiodonium diyne salts and sodium/ -toluenesulfinate (see equation 57)86. 

Palladium. Flame AAS analysis of Pd is described in P CAM 173 however, it would probably be preferred to use graphite furnace atomization as in S-191 Pt, soluble salts. An oxidizing air-acetylene flame is used for Pd AAS to minimize interferences from Al, Co, Ni, Pt, as well as Rh and Ru. These interferences may be minimized by complexation of Pd as the bis-pyridine-dithiocyanate (13) and extraction into hexone (3). Interferences may be minimized by the addition of 1000 ppm La. The 244.8 and 247.6 nm lines have equal sensitivity however, the 247.6 nm line is generally preferred ( 3). No Federal standard exists for Pd however, in analogy to Ni and Pt, Pd should be treated with caution. 

Tellurium dithiocyanate is known only in the form of its yellow complexes with thioureas. These complexes were prepared from bis[thiourea]tellurium dihalides and potassium or ammonium thiocyanate in aqueous or methanolic media. 

Tetrakis[thiourea]tellurium Dithiocyanate6 3.0 g (7.6 mmol) of bis[thiourea]tellurium dithiocyanate are dissolved in 75 ml of 10% aqueous thiourea solution at 40°. The solution is filtered, the filtrate is kept at 20° overnight, and the deposited crystals are collected yield 3.4 g (72%). 

A single-crystal X-ray structural analysis of bis[ethylenethiourea]tellurium dithiocyanate showed the tellurium atom to be coordinated to four sulfur atoms with planar trans-arrangement of the ligands1. 

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