Halides and Sulfides

This chapter does not introduce new chemical reactions. On the contrary, mainly elementary reactions are employed. The attempt is made here to provide an introduction into the planning of syntheses of simple target molecules based upon the synthon approach ofE.J. Corey (1967A, 1971) and the knowledge of the market of fine chemicals . 

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What other combination of alkyl halide and sulfide will yield... 

What other combination of alkyl halide and sulfide will yield the same sulfonium salt shown in the preceding example Predict which combi-nation will yield the sulfonium salt at the faster rate. ... 

The most important gaseous component is X2, as is the case in most oxides, halides, and sulfides. The stoichiometric variation will be linked to the partial pressure of the surrounding nonmetal atmosphere. The nonmetal component will be gained at high pressures and lost at low pressures. These options correspond to oxidation and reduction. 

This structure is commonly adopted by oxides, nitrides halides, and sulfides MX, including the nonstoichiometric 3d transition-metal oxides TiO, VO, MnO, FeO, CoO, and NiO. 

Like the oxide, halides and sulfide, the nitride, boride, and carbide of htanmm(IV) can be made by heating the elements together at high temperatures. The last three compounds are alloy-like in character, they can vary in composition without becoming unstable and they are extremely hard. 

Foresti, M.L., Innocenti, M., Forni, F. and Guidelli, R. (1998) Electrosorption valency and partial charge transfer in halide and sulfide adsorption on Ag(lll). Langmuir 14, 7008-7016. 

At present, essentially the halide, pseudo-halide and sulfide anions have been shown to react with e+, either directly [3, 6, 25,46,48] or after previous e capture by hologenated compounds (see Figs. 4.4 and 4.6) [19, 20]. However, it is not excluded that most anions are able to react with the positron. 

Hansen, Lamm, and Ruzicka described the Selectrode (trademark of Radiometer A/S), which involves a specially treated graphite electrode in direct contact with an electroactive surface. Typical is the halide electrode, involving a layer of silver halide and sulfide in direct contact with a graphite electrode that has been rendered hydrophobic by treatment with Teflon. Another example is the Cu(II) electrode, based on a similar preparation using CuS or CuSe. The Selectrodes couple an electronic conductor directly to the solid-state detector, which is an ionic conductor. Althou the mechanism of coupling is not clear. Buck suggested that an interfacial potential can be communicated through solid-state equilibria to the electronic conductor without the intervention of a redox process. 

COUPLING OF C(ip )-ORGANOMETALUCS WITH ARYL O, S AND Se COMPOUNDS COUPLING OFC(jp )-ORGANOMETALLICS WITH POLYFUNCTIONAL AROMATICS COUPLING OFC(jp )-ORGANOMETALUCS WITH HETEROAROMATIC HALIDES AND SULFIDES Furans and Thiophenes... 

COUPLING OF C(s/ 3).orgANOMETALLICS WITH HETEROAROMATIC HALIDES AND SULFIDES... 

Nickel- or palladium-catalyzed coupling reactions of alkyl Grignard or zinc reagents can be applied to heteroaromatic halides and sulfides. The characteristic features are, therefore, based on those described in the preceding sections and hence details are not repeated in this section. Aspects are summarized by the types of heteroaromatic compounds NiCh(DPPP) is used as catalyst, unless stated otherwise hereafter. 

The HOMO of OH" is higher than the LUMO of I2, which indicates that two-electron transfer from OH to I2 should be facile. However, the reaction is reported to be slower in seawater, and I2 appears to react with reduced organic matter (21-23). HOI in turn reacts with organic matter to produce I" and RI (3, 24). Thus iodide oxidation leads to electron acceptors as intermediates that can eventually re-form iodide. In contrast, sulfide oxidation leads to strong electron donors such as the polysulfides, which oxidize back to SO/ , as the intermediates (25). Thus, halides and sulfide have a significant difference in their environmental cycling, despite their isoelectronic nature. 

One of the most synthetically valuable reactions of tetraorganostannanes is the ally-lation which includes homolytic cleavage of allyl-tin bonds. The radical chain reactions of allylstannanes with alkyl halides and sulfides effected with radical initiators or photoirradiation afford the corresponding substitution products (eq (110)) [105]. 

There are other types of solid membranes which are used in ion-selective electrodes. An important group are those based on silver halides and sulfides. In these systems the ionic conductor is Ag. These membranes function in the same manner as other ionic solids in which one ion has a very diflferent conductivity than the other. Thus, the above analysis is also applicable to these systems. 

Barium reduces the oxides, halides, and sulfides of most of the less reactive metals, thereby producing the corresponding metal. It has reportedly been used to prepare metallic americium via reduction of americium trifluoride (13). However, calcium metal can, in most cases, be used for similar purposes and is usually preferred over barium because of lower cost per equivalent weight and nontoxicity (see ACTINIDES AND TRANSACTINIDES). 

Russell s studies of vinylation reactions using vinylstannanes also examined similar reactions of vinyl sulfides, sulfoxides and sulfones [43a]. For example, isopropyl radical, generated from isopropyl mercuric chloride, adds to the non-sulfur-substituted alkene carbon of compounds 96, 97 and 98 to form the vinylated product 99 (Scheme 19). Recently, Caddick applied an intramolecular version of this process using alkyl halides and sulfides or sulfoxides in the presence of tributyltin hydride to the synthesis of indole derivatives [57]. 

The most important MX structures involving tetrahedral coordination are the cubic ZnS sphalerite (Fig. 5a) and the hexagonal ZnS wurtzite (Fig. 5b) arrangements. It is striking that halides and sulfides of metal ions with d5 and d10 shells have a tendency to crystallize in the sphalerite structure for example, the cuprous halides, Agl, HgS, MnS, CdS, and ZnS. (The last three also occur in the wurtzite modification, as do the oxides of Zn and Be). (See Table V.) Here again, the simple ionic theory fails to account for the facts for (1) the radius ratios of some of these compounds are compatible with a 6-coordinated structure, and (2) interatomic distances calculated from the usual ionic radii (decreased by 5% to com-... 

Over 75% of inorganics and 95% of intermetallics crystallize in crystal structures having 90° and 120° interaxial angles of the unit cell. The residual compounds for inorganics are mainly oxides, halides, and sulfides, while those for the intermetallics are Se, Te, and S compounds. These compounds represent the boundary compounds between the inorganics and the intermetallics. 

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