Some Specific Examples

Suitable oxidizing agents are [FeCp2] or Ag, while the cationic species may be reduced back to the alkyne complexes using CoCp2. Some of this chemistry has been reviewed [216]. 

Oxidation of trows-RuCl(C=CCH Ph2)(dppe)2 favors hydrogen atom transfer leading to frons-[RuCl(=C=CHCHPh2)(dppe)2] [217]. Chemical oxidation of Ru (C=CRc)(PPh3)2Cp (Rc = ruthenocenyl) gives the cydopentadienylidene-ethylidene 

Oxidation ]PhIO or Cu(OAc)2] of ]Fe(=C=CHMe)(dppe)Cp] affords bis(vinyli-dene) ] Fe(dppe)Cp 2(p-C4Me2)], possibly via an intermediate radical cation ]222]. Similar oxidative coupling of cyclopropenyl Ru C=CPhCH(CN) (PPh3)2Cp affords bis(vinylidene) ] Cp(Ph3P)2Ru =C=CPhCH(CN)2 2] which, in turn, can be de-protonated to the bis(cydopropenyl) ]223]. Oxidation of ]Ru(N4Meg)(=C=CH2)] with PhNj or ]FeCp2]+ affords ] Ru(N4Meg) 2(p-C=CHCH=C)] ]51]. 

Ready addition of nucleophiles (Nu ) to metal-allenylidene complexes affords alkynyl derivatives. Subsequent protonation or alkylation, as described in Section 1.2.3 above, then gives the corresponding vinylidene complexes (Equation 1.8)  

For example, addition of LiBu to Mn(=C=C=CPh2)(CO)2Cp, followed by protonation or methylation gives Mn =C=CR(CPh2Bu ) (CO)2Cp (R=H, Me) [224]. This is a method which has not been employed generally, and could perhaps be exploited to produce more unusual derivatives. 

Mutations in CYP2D6 (25) may lead to three kinds of functional changes absence, decrease, or increase of enzyme activity. Lack of enzyme activity indicates in most cases a frameshift mutation or a splicing defect, but there is also a case of totally missing enzyme formation. Decreases of enzyme activity indicate a change of enzyme structure these can be clinically treacherous since the decrease may differ in severity for different sustrates. Enhanced enzyme activity indicates usually gene duplication, sometimes multiplication a case of 13-fold multiplication has been observed. Everyone of these enzyme changes may differ between human populations. 

The deficiency of CYP2D6 was discovered in England by testing deb-risoquine as a substrate (28), in Germany by testing sparteine (29). The fact that the deficiency of a single enzyme was responsible for both deficiencies was demonstrated later (30) the correlation coefficient of the rates of 

The variants 4A and 4B represent enzymes without activity, all others have reduced activity compared to the wildtype. The + sign at CUP2D6 10C indicates exon 9 conversion into that of pseudogene CYP2D7. 

Source The data are compiled from information on CYP2D6 nomenclature by Daly et al. (27), which details the numerous original sources of the data, and on the overview by Marez et al. (26). 

Many African data were due to the variant CYP2D6 17 which has reduced activity. This variant occurred with an allele frequency of 37% in Zimbabwe, of 17% in Tanzania, and in 9% in Ethiopia (8). The reduced enzyme activity in Asia is due to a different variant, CYP2D6 10 characterized by C188T, which has in China a frequency of 51%. Besides their generally reduced activity, the Asian and African variants have no similarity. The activities of these variants towards different substrates requires much additional investigation. 

Simple alloy deposition is observed for the Pb-Sn couple. The standard potentials of the two metals are = -0.13 V and -0.14 V vs. SHE, respectively, hence it is easy to adjust the concentrations in solution such that the reversible potentials would be the same, or close to each other. Although plating occurs at a potential negative with respect to the reversible potential for hydrogen evolution, both metals are very poor catalysts for this reaction, so that close to 100% Faradaic efficiency is readily obtained. The most important consequence of this is that the composition of the plated alloy is linearly related to the composition of the solution. This is, unfortunately, not common in alloy plating, as we show next. 

Induced co-deposition is observed for deposition of metals that cannot be deposited at all from an aqueous solution, such as W, or can barely be deposited, with a low current efficiency and poor adherence of the deposit, such as Re. However, alloys of W with the iron-group metals can readily be formed, using, for example, a solution of NiS04 and Na2W04, with citric acid added as a complexing agent. In this particular case it was shown that a Ni-W alloy is deposited from a complex containing both metals, while Ni is also deposited in parallel reactions from its complex with citrate. Very similar behavior is observed for deposition of alloys of molybdenum. 

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Some specific examples of the use of data gathered while monitoring the reservoir will now be discussed. 

A large variety of organic oxidations, reductions, and rearrangements show photocatalysis at interfaces, usually of a semiconductor. The subject has been reviewed [326,327] some specific examples are the photo-Kolbe reaction (decarboxylation of acetic acid) using Pt supported on anatase [328], the pho-... 

Figure 3-16. A reaction scheme that changes the number of bonds at one atom, and some specific examples.

The choice of the best method for answering this question is governed by the specific nature of the system under investigation. Few general principles exist beyond the importance of analyzing a representative sample of suitable purity. Our approach is to consider some specific examples. In view of the diversity of physical methods available and the number of copolymer combinations which exist, a few examples barely touch the subject. They will suffice to illustrate the concepts involved, however. 

Some specific examples include the noncatalytic reaction of acrylamide with primary amines to produce a mono or bis product (5). 

General arylation reactions are summarized by the following equations and some specific examples are presented in Table I. 

Major applications of CL microscopy and spectroscopy in the analysis of solids have been listed in the Introduction. Some specific examples of CL applications are outlined below. 

As this field is very wide, we will discuss first the gases that can be used to study metal dispersion by selective chemisorption, and then some specific examples of their application. The choice of gases, is, of course, restricted to those that will strongly chemisorb on the metal, but will not physically adsorb on the support. Prior to determining the chemisorption isotherm, the metal must be reduced in flowing hydrogen details are given elsewhere. The isotherm measurement is identical to that used in physical adsorption. 

Discuss how carbon adsorption works and how it can be used in water treatment applications. Give some specific examples where this technology is used to remove specific contaminants. 

What do we mean when we speak of an inherently safer chemical process Inherent has been defined as existing in something as a permanent and inseparable element, quality, or attribute (American College Dictionary, 1967). A chemical manufacturing process is inherently safer if it reduces or eliminates the hazards associated with materials and operations used in the process, and this reduction or elimination is permanent and inseparable. To appreciate this definition fully, it is essential to understand the precise meaning of the word hazard. A hazard is defined as a physical or chemical characteristic that has the potential for causing harm to people, the environment, or property (adapted from CCPS, 1992). The key to this definition is that the hazard is intrinsic to the material, or to its conditions of storage or use. Some specific examples of hazards include ... 

Basic process chemistry using less hazardous materials and chemical reactions offers the greatest potential for improving inherent safety in the chemical industry. Alternate chemistry may use less hazardous raw material or intermediates, reduced inventories of hazardous materials, or less severe processing conditions. Identification of catalysts to enhance reaction selectivity or to allow desired reactions to be carried out at a lower temperature or pressure is often a key to development of inherently safer chemical synthesis routes. Some specific examples of innovations in process chemistry which result in inherently safer processes include ... 

Choosing a model chemistry almost always involves a trade-off between accuracy and computational cost. More accurate methods and larger basis sets make jobs run longer. We ll provide some specific examples of these effects throughout the chapters in this part of the book. 

Ketones, esters, and nitriles can all be alkylated using LDA or related dialkyl-amide bases in THE. Aldehydes, however, rarely give high yields of pure products because their enolate ions undergo carbonyl condensation reactions instead of alkylation. (We ll study this condensation reaction in the next chapter.) Some specific examples of alkylation reactions are shown. 

Most communication systems can be separated into the basic components shown in Fig. 4-la. Figures 4-lb, c, d, e show some specific examples of how particular systems can be separated into these components. There is, of course, considerable flexibility in this separation sometimes it is convenient to consider an antenna as part of the channel, and sometimes as part of the coder or decoder. Here... 

The influence of the system parameters P, d, and G on the burn-out flux are not easily seen from the y values in Table II, and it is therefore helpful to illustrate the general trends by considering some specific examples, using the correlation to obtain burn-out flux values. 

Fig. la —c. Schematic drawing of some specific examples of polymer molecules at an interface (a) the free surface of a homopolymer, (b) the surface enrichment of one component in a miscible polymer blend, and (c) the interface between polymers of different molecular weight and/or chemical composition... 

In this part of our review, surface properties of some specific examples of siloxane... 

The maintenance of a connection to experiment is essential in that reliability is only measurable against experimental results. However, in practice, the computational cost of the most reliable conventional quantum chemical methods has tended to preclude their application to the large, low-symmetry molecules which form liquid crystals. There have however, been several recent steps forward in this area and here we will review some of these newest developments in predictive computer simulation of intramolecular properties of liquid crystals. In the next section we begin with a brief overview of important molecular properties which are the focus of much current computational effort and highlight some specific examples of cases where the molecular electronic origin of macroscopic properties is well established. 

Here are some specific examples illustrating chemical formulas of ionic compounds. 

The most common method of isolation and sample cleanup involves contacting a filtered aqueous solution with an appropriate immiscible organic solvent in a. aboratory separatory funnel of appropriate size. Some specific examples are discussed later. With multicomponent samples a single solvent or solvent mixture is unlikely to extract all components equally causing discrimination. Ihis discrimination may be useful if the solvent discriminates against the extraction of solutes that are not of interest in the analysis. 

Scheme 2.4 provides some specific examples of facial selectivity of enolates. Entry 1 is a case of steric control with Felkin-like TS with approach anti to the cyclohexyl group. 

Scheme 4.7 gives some specific examples of these types of reactions. Entry... 

Physical metallurgy is concerned with the scientific study of materials. Phase transformations, recovery and recrystallization, precipitation hardening, structure-property correlations, characterization of microstructure by microscopy (optical, electron and field-ion), are some specific examples among the many topics covered under physical metallurgy. 

Some specific examples in the field of sulfide flotation will now be described. 

The electrochemical process differs from the chemical process by the fact the solid to be dissolved has to be electrically conducting (as for example, a metal), or a semiconductor (as for example, certain oxides and metal sulfides). As some specific examples of dissolution occurring electrochemically, mention may be made of (i) metals in oxygenated water,... 

Since this book is primarily concerned with condensed-phase studies, we do not go into the details of gas-phase radiation chemistry. We will briefly outline some important mechanisms of gas-phase reactions, followed by a presentation of some specific examples and certain theoretical considerations. In Chapter 4, we considered ionization and excitation in some detail. Many of these considerations apply to the gas phase these will not be repeated. We stress that the measurement of the W value is of utmost importance in the... 

Gas-phase radiolysis can sometimes result in chain reactions involving H atoms or other radicals. As in other cases with chain reactions, termination is due to either recombination or reaction with other radicals. Typical chain length is -1000 or more. Some specific examples will be considered in Sect. 5.2. 

A range of various substances may be added to a purified therapeutic protein in order to stabilize that product (Table 6.7). Such agents can stabilize proteins in a number of different ways, and some specific examples are outlined below. 

Notice that the results obtained so far (Eqs. (19) and (23) for the Maxwell field and Eqs. (20) and (24) for the Dirac field) are particular cases of the above expressions, corresponding to a = (/3,0,0,0) and a = (0,0,0,i2L) respectively. Another important aspect is that T 11) ) is traceless in both cases, as it should be. Now, we will apply these general results to some specific examples. 

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