Oxidation States of Sulfur

Type B (redox) reactions are more complex. Sulfide in this reaction is converted into some other oxidation state of sulfur. For example, sulfides can be converted to a zero oxidation state of elemental sulfur by oxygen ... 

Similar calculations have been applied to the 3-substituted thietane dioxide series (i.e. 188(1 -3))198, assuming that only the constant C in the Karplus equation should be significantly affected by the substituents and by the oxidation state of sulfur. The results thus obtained were in poor agreement with X-ray data. 

A good correlation with ordinary Hammett a values was based on 16 well-behaved substituents, and p-SOMe conformed well to this. Various other substituents showed deviations which were attributed to enhanced + R effects. These included p-SPh and this was explained in terms of 7t(pd) bonding, which was thus taken to play no part in the effect of p-SOMe on the methyl hyperfine splitting. More recently several 4-substituted benzyl radicals of the type RSO C6H4CH2 (n — 0,1 or 2 R = Me, Ph, Tol, COMe or OMe) have been examined by ESR spectroscopy249. The ability to delocalize spin density onto the substituent decreases in general as n increases and the effect of R depends on the oxidation state of sulfur. These authors have devised a new scale of substituent effects (sigma dot... 

The preparation of alkyl benzenesulfenates is accompanied by the formation of products of higher oxidation states of sulfur. These products have higher boiling points and are separated by careful distillation of the product under reduced pressure. 

I. Descriptive Chemistry of the environmentally important oxidation states of sulfur. 

The various oxidation states of sulfur have been determined by polarography. The electrochemical oxidation of sulfide ions in aqueous solution may lead to the production of elementary sulfur, polysulfides, sulfate, dithionate, and thiosulfate, depending on the experimental conditions. Disulfides, sulfoxides, and sulfones are typical polarographically active organic compounds. It is also found that thiols (mer-captans), thioureas, and thiobarbiturates facilitate oxidation of Hg resulting thus in anodic waves. 

Eehrmann R, Bjerrum NJ, Poulsen EW (1978) Lower oxidation states of sulfur. 1. Spectrophotometric study of the sulfur-chlorine system in molten sodium chloride-aluminum chloride (37 63 mol%) at 150 °C. Inorg Chem 17 1195-1200... 

The more electronegative element will take the negative oxidation state, (a) The maximum oxidation state of sulfur is +6 the most common negative oxidation number of oxygen is -2. Therefore, it takes three oxygen atoms to balance one sulfur atom, and the formula is SO v (b) The maximum oxidation state of carbon is +4 the only oxidation number of fluorine in its compounds is - 1. Therefore, it takes four fluorine atoms to balance one carbon atom, and the formula is CF4,... 

Ans. SF6, SF4, and SF2. The oxidation states of sulfur in these compounds correspond to the maximum oxidation state for a group VI element and to states 2 and 4 lower. (See Fig. 13-1.)... 

Different oxidation states of sulfur have also been explored, particularly sulf-ones and sulfonamides as transition state analogs of lysine deacetylation, but without much success. The monodentate SAHA-like methyl sulfoxide 7 proved most potent, but still with an enzyme IC50 of only 48 pM and indications of HDAC/TDAC selectivity in cellular assays [28]. 

Reduction of Disulfides and Other Oxidation States of Sulfur... 

Some other oxidation states of sulfur can be reduced but not sulfonic acids or, as mentioned above, sulfones. 

Varaivamurthy A, Manowitz B, Luther GW, Jeon Y. 1993. Oxidation state of sulfur in thiosulfate and implications for anaerobic energy metabolism. Geochim Cosmochim Acta 57 1619-23. 

The high nucleophilicity of heterosubstituted allyllithium compounds makes them attractive reagents in synthetic organic chemistry. Structural studies of these compounds give a fundamental understanding about the control of the regioselectivity. Often, these studies are difficult due to the tendency of the compounds to form complex fluxional aggregates in solution. Piffl and coworkers have studied the dependency of the oxidation state of sulfur on the structure and electronic properties of the heterosubstituted... 

A good variety of compounds have been prepared and characterized allowing us to obtain reliable information on the chemical shifts of saturated and unsaturated ring protons. A selection of different structures are shown in Table 4. The thiazine derivatives have been organized in groups for comparison. The effects of saturation (54, 105, 106), substituents of variable electronegativity (107, 108), increasing oxidation state of sulfur (121, 122, 27-29), and deprotonation (109-111) can be observed. 

Although NMR spectroscopy has been used on 1,4-oxazines only from the late 1970s, there are sufficient data for almost all types of thiazine carbons. A selection is presented in Table 5. Generally the carbons adjacent to nitrogen have higher shifts than the carbons adjacent to sulfur, but substituents and the oxidation state of sulfur have large effects. 

Regardless of the oxidation state of sulfur, the nitrogen of 4/7-1,4-thiazines is almost as easy to alkylate as an amine, as can be seen from the reactions of 109 <1967JME501>, 186 <1969JHC247>, and 187 <1976JPR865>, whereas the only 2/7-1,4-thiazine that could be N-alkylated is the silyl iminol ether 112 <1988JME1575> (Scheme 13). 

Substituents attached to a heterocyclic ring through a sulfur atom exist in wider variety than those through oxygen. Besides the simple thio analogues—the thiols (mercaptans), thioethers, thioesters and the like—they include compounds of various higher oxidation states of sulfur, including sulfoxides, sulfones, sulfinic and sulfonic acids and their derivatives. 

Note that some reactions are reversible (indicated by . "), whereas others are irreversible under environmental conditions. The dotted arrow indicates that, in principle, a reaction is possible, but no clear evidence exists showing that the reaction proceeds abiotically in the dark. b For oxidation states of nitrogen in various functional groups see Table 2.5. c For oxidation states of sulfur in various functional groups see Table 2.6. 

Table 4.11 Relative Rates of Reaction of Various Nucleophiles with Different Oxidation States of Sulfur in 60% Aqueous Dioxane...

What is the oxidation state of sulfur in each of the following compounds ... 

A possible coordination to specific metal ions controlled by the oxidation state of sulfur... 

Kice, J. L., Nucleophilic Substitution at Different Oxidation-States of Sulfur 17 147... 

C-H bond energies. Therefore, such a dramatic increase in the reactivity of OH towards DMSO compared to DMS would not be expected if an abstraction mechanism was operative in each case. It is possible that the presence of the O in DMSO or the higher oxidation state of sulfur is increasing the reactivity of the molecule toward an addition type of reaction. The reaction of the addition aduct, OH-DMSO, with Oj could lead to an enchancement of the effective rate constant. Such a mechanism has been envoked to explain the dependence of the rate constant for the reaction of OH with CS2 on tne partial pressure of O2 in the reaction system (26.271 The detection of both SO2 and DMSO2 as reaction products, as described below, indicates that both addition and abstraction reaction pathways are operative. 

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