Stoichiometric addition compound

Bismuth(III) oxide, Bi O is the compound produced by heating the metal, or its carbonate, in air. It is definitely a basic oxide, dissolving readily 111 acid solutions, and unlike the arsenic or antimony compounds, not amphiprotic in solution, although it forms stoichiometric addition compounds on heating with oxides of a number of other metals. It exists in three modifications, white rhombohedral, yellow rhombohedral, and gray-black cubical, Bismuth(II) oxide. BiO, has been produced by heating die basic oxalate. 

Binary liquid mixtures are known in which the solid that appears when the mixture is cooled is a compound containing both components in a fixed proportion. This kind of solid is called a solid compound, or stoichiometric addition compound. Examples are salt hydrates (salts with fixed numbers of waters of hydration in the formula unit) and certain metal alloys. 

Senti and Witnauer206 have reported studies on the fiber diagrams from various alkali-amyloses. Specimens were obtained by deacetylating clamped specimens of amylose acetate with the appropriate alkali. The positions of the alkali ions and the lateral packing of the amylose chains were determined with the aid of Patterson projections. In the A - and B -modifica-tions, the fiber period was 22.6 A. (extension of 6 D-glucose units), whilst in the V -modification it was 8.0 A. These authors have also studied in detail the addition compounds of amylose and inorganic salts with special reference to the structure of the potassium bromide-amylose compound.206 Oriented alkali fibers were treated with the appropriate salt solution. Stoichiometric compounds were formed. The x-ray patterns from these showed that the addition compounds with potassium salts crystallized in... 

The catalyst is generally a palladium compound promoted with a trivalent amine or phosphine in the presence of methyl iodide as described earlier. Systems proven to bias acetaldehyde are utilized, of course (e.g. see Table I, run 12). A yield of 85% acetaldehyde from methyl acetate is typical by this method. It can be utilized in stoichiometric addition to easily prepared acetic anhydride resulting in EDA formation. When considering that the "boiling pot" reaction by-products are recyclable acetic acid, acetic anhydride and small amounts of EDA, the yield to vinyl acetate related products is 95%. 

The formation of chiral alcohols from carbonyl compounds has been fairly widely studied by reactions of aldehydes or ketones with organometallic reagents in the presence of chiral ligands. Mukaiyama et al. 1081 obtained excellent results (up to 94% e.e.) in at least stoichiometric addition of the chiral auxiliary to the carbonyl substrate and the organometallic reagent. 

But, at the stoichiometric composition, rt = n2, since we have a 1 1 addition compound, and equation (14.9) becomes... 

SrjCrNbOj 53 is a semiconductor with a room-temperature resistivity, of ca. 250 Q-cm p increases rapidly with decreasing temperature and at low temperature p is larger than the limit of our instrument. Nevertheless, pRj is significantly lower than that in the stoichiometric parent compound, SrjCrNbO this behavior is attributed to the additional electrons of Nb " in the reduced phase. 

Compositional names are either of the stoichiometric type (which, furthermore, are of the binary type except in the case of homoatomic species) or of the addition compound type. Compositional nomenclature is used if little or no structural information is to be conveyed... 

While the scope is somewhat limited and the yields are only moderate, this process provides a very direct and convenient route to 2,3-disubstituted indenones that would be quite hard to prepare by most other procedures. Mechanistically, it is not clear if this reaction proceeds by addition of the vinylic palladium intermediate across the aldehyde moiety and subsequent p-hydride elimination, or whether the aldehyde C-H bond undergoes oxidative addition to the vinylic palladium intermediate and two subsequent reductive eliminations generate the final indenone product. Related stoichiometric arylpalladium compounds have been reported to react with alkynes to afford both indenones and indenols [109,130]. 

The o-complexes of nitroaromatic compounds with the cyanide ion were prepared by stoichiometric addition of CN to solutions of nitroarenes in DMF + 0.1 M TBABF4 under inert atmosphere. The electrochemical experiments (cyclic voltammetry and electrolysis) are analogous, as it has been described for 3H (Sect. 2.3). The results are summarized in Table 2. 

In the present section, we review the properties of the stoichiometric Ce compounds exhibiting competition between heavy-fermion superconductivity and long-range magnetic order. We shall not discuss the highly complex phase diagrams obtained in alloy systems. In addition, we summarize recent attempts at a theoretical description of the complex low-frequency dynamics resulting from the competition between Kondo effect and RKKY interaction. 

Volumetric methods are applicable to the analysis of sugar-bisulfite addition compounds, since, being products of a completely reversible reaction, they can be separated into their components stoichiometrically in a reaction system readily amenable to detection of the desired equivalence point within an analytically practical period of time. Attainment of acceptable precision is dependent on proper significance being attributed to factors which may affect the equilibrium rates namely, temperature,... 

The direct, Pd(II)-catalyzed addition of heteroatom and stabilized carbon nucleophiles to alkenes is generally not a successful reaction. An exception is the addition of water, which gives carbonyl compounds and has been developed into an important indnstrial process, the Wacker process. This has been reviewed extensively.By contrast, the stoichiometric addition of nucleophiles such as amines is facile. - However, if alkenes could be converted catalytically into Tr-allylpalladium complexes, the problems with nucleophilic addition to alkenes could be circumvented and amines and other heteroatom nucleophiles could be employed. A range of alkenes have been converted into rr-allyl complexes in a stoichiometric fashion,t "t but catalytic reactions have proved more difficult. However, aUyl acetates and similar compounds readily exchange the acetate group for heteroatom nucleophiles in a Pd(0)-catalyzed reaction, which proceeds via 7T-allylpalladinm(ll) intermediates (Scheme 1). Since this reaction has been developed into a very important synthetic reaction, an efficient procedure for catalytic conversion of alkenes into aUyl acetates would have great synthetic potential. 

In addition, the lanthanide ions are always embedded in a chemical environment. This environment might be either inorganic or organic. Both types of compounds may be stoichiometric compounds where a lanthanide ion represents at least 1 equiv. of the total composition, or doped compounds where the lanthanide ions are only present as impurities in a defined matrix (thus representing a small percentage of the total composition). A typical example of a lanthanide-doped material is an inorganic phosphor. On the other hand, a typical example of a stoichiometric lanthanide compounds is a lanthanide complex where ideally all the lanthanide ions are surrounded by the same coordination sphere. 

Although the enantioselective stoichiometric addition of chiral aryltitanium reagents have been reported in 1987 [66], the catalytic enantioselective aryl addition to carbonyl compounds with titanium catalyst was realized by Walsh using the catalyst prepared from bis(sulfonamide) ligand and Ti(OTr)4 with diarylzinc as the nucleophiles, to afford the tertiary alcohol in good to excellent enantioselectivities for a range of ketone substrates [67]. Very recently, Gau reported that... 

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