Thiocyanate reaction with

The reaction of phenylazoalkenes 424 with an excess of potassium thiocyanate in acetic acid produces the cycloadducts 425 that undergo further [3+2]-cycloaddition reaction with thiocyanic acid at the azomethine imine function giving rise to the bicyclic product imidazo[l,5-3][triazole]-2,5-dithiones 41 (Equation 87) <1998SL786>. 

Prom Epoxides sod Thiourea or Other Thioamidex Epoxides react with thiourea in a manner analogous with their reaction with thiocyanate ion. 

The reaction with thiocyanate yields a /i-amido bis(tetraammine-thiocyanatocobalt(III) complex (377). The kinetic data are consistent with a dominant reaction path such as in Eq. (66) (377, 381). There is... 

Although the redox potential of-OH is very high [E( OI I/OE I ) = +1.9 V (Klan-inget al. 1985) E(-OH, H+/H20) = 2.73 (Wardman 1989)], direct ET is rarely observed in OH-reactions, and where it occurs intermediate complexes are likely to be involved. For example, in its reaction with thiocyanate, where the final product is the three-electron bonded dirhodane radical anion [reaction (31) for other three-electron bonded systems, see Chaps. 5 and 7], a similar three-electron bonded intermediate might precede ET [reactions (29) and (30)]. 

The widespread occurrence of iron ores, coupled with the relative ease of extraction of the metal, has led to its extensive use as a constructional material with the result that the analysis of steels by both classic wet and instrumental methods has been pursued with vigour over many years.3 Iron complexes are themselves widely used as the basis of convenient analytical methods for the detection and estimation of iron down to parts per million. Familiar tests for iron(III) in aqueous solution include the formation of Prussian blue as a result of reaction with [Fe(CN)6]4, and the formation of the intensely red-coloured [Fe(H20)5SCN]2+ on reaction with thiocyanate ion.4 Iron(II) forms particularly stable red tris chelates with a,a -diimines such as 1,10-phenanthroline or 2,2 -bipyridine that have been used extensively in spectrophotometric determinations of iron and in the estimation of various anions.5 In gravimetric estimations, iron(III) can be precipitated as the insoluble 8-hydroxyquinoline or a-nitroso-jS-naphthol complex which is then ignited to Fe203.6 In many situations the levels of free [Fe(H20)6]3+ may be controlled through complex formation by addition of edta. 

Direct interference from the bromate-HCl reaction should be too slow to be significant. Although extensive formation of a complex e.g. Br02SCN) followed by rate-determining reaction with thiocyanate ion and an alternative (chloride ) path, viz. 

Rate laws and kinetic parameters for substitution reactions at complexes Cp2TiX2 in acetonitrile solution at 298.2 K have been reported (X = halide or alkoxide). Reactivities are discussed in terms of the nature of the leaving group, the entering group, and the non-leaving Cp ligand. A volume of activation of —15 cm3 mol-1 has been determined for the reaction with thiocyanate.1124... 

One special case of indirect ampHfication via iodine oxidation is offered by the reaction with thiocyanate in sodium bicarbonate alkafine medium (reaction [XIV]) ... 

Spectrophotometric determination of molybdenum can be accomplished by reaction with thiocyanate in an acid medium in the presence of tin(II) chloride (465 nm). Toluene-3,4-dithiol, usually referred to as dithiol, can also be used as a spectrophotometric reagent for molybdenum determination. In an acid medium, it forms a green complex that can be extracted using organic solvents. 

The ferrocene coronands 31 undergo reversible one-electron oxidation [72] and the redox potential is usually sensitive to metal-ion complexation by the crown ether part of the molecule. Such complexes have been prepared in reactions with thiocyanates, MSCN (M = Li, Na, K) [71]. The macrocyclic ligands extract thal-... 

---