Equimolar stoichiometric complex

A stoichiometric complex maybe formed under suitable circumstances. An equimolar (1 1) complex is formed between digitonin and cholesterol or sodium cetyl sulfate and cholesterol, while digitonin and cholesterol are believed to form a 1 2 complex in the interface. 

Complex formation between a polycation and a polyanion is also called polysalt formation or coacervation. If, for example, a solution of poly(sodium styrene sulfonate) (III) is added to an equimolar solution of poly(4-vinyl pyridinium hydrogen bromide), then a stoichiometric complex with respect to the side groups is formed, and this occurs at every mixing ratio (Figure... 

When equal amounts of solutions of poly(ethylene oxide) and poly(acryhc acid) ate mixed, a precipitate, which appears to be an association product of the two polymers, forms immediately. This association reaction is influenced by hydrogen-ion concentration. Below ca pH 4, the complex precipitates from solution. Above ca pH 12, precipitation also occurs, but probably only poly(ethylene oxide) precipitates. If solution viscosity is used as an indication of the degree of association, it appears that association becomes mote pronounced as the pH is reduced toward a lower limit of about four. The highest yield of insoluble complex usually occurs at an equimolar ratio of ether and carboxyl groups. Studies of the poly(ethylene oxide)—poly(methacryhc acid) complexes indicate a stoichiometric ratio of three monomeric units of ethylene oxide for each methacrylic acid unit. 

From the reaction of equimolar amounts of CuXj and Cu(Et2C fc)2, XCu(Et2rffc) is formed 135, 99), which can be obtained also by the oxidation of [Cu(Et2rffc)]4 with Xj in stoichiometric quantities 99). A remarkable feature of these complexes is their... 

For successful operation a selective CO oxidation catalyst in a reformer-PEFC system must be operated at ca. 353-373 Kin a complex feed consisting of CO, 02, H2, C02, H20 and N2, and be capable of reducing CO concentrations from about 1% to below 50 ppm - this is equivalent to a CO conversion of at least 99.5% [4, 54, 60], In addition, this conversion must be achieved with the addition of equimolar 02 (twice the stoichiometric amount) and the competitive oxidation of H2 must be minimized. This is expressed as selectivity, which is defined as the percentage of the oxygen fed consumed in the oxidation of CO for commercial operation a selectivity of 50% is acceptable, since at this selectivity minimal H2 is oxidized to water. 

An iridium(l) complex, generated from l/2[Ir(OMe)(COD)]2 and 4,4 -di-/-butyl-2,2 -bipyridine (dtbpy), catalyzed the direct borylation of 2-substituted pyrroles in stoichiometric amounts relative to 2,2 -bi-l,3,2-dioxaborolane 785 in hexane at room temperature (Equation 188) <2003ASC1103>. The pyrrolylborates 786 from regioselective C-H activation at the 5-position were formed in high yields. Similar borylation of unsubstituted pyrrole with an equimolar amount of borolane 785 regioselectively provided 2,5-bis(boryl)pyrrole 787 (Equation 189). 

A large number of complex halides are known and have been reviewed. The most conunon complex fluorides involve the TiFs" moiety. Complexes are conveniently prepared by adding [N(n-Pr)2H2]F and a stoichiometric amount of the donor to a solution of TiF4. Alternatively, an equimolar quantity of [N(n-Pr)2H2]2[TiF6] is added to a solution of TiF4L2. Solutions formed by the former method that do not form [TiFsL]" were shown by F NMR to contain the [Ti2Fii] moiety. ... 

The mechanism proposed for the pyruvate ferredoxin oxidoreductase is drastically different from that of the pyruvate dehydrogenase enzyme complexes, as radical intermediates are proposed, suggesting stepwise one-electron transfers. Furthermore, the preliminary work by Uyeda and Rabinowitz (211) on the mechanism of C. acidiurici pyruvate ferredoxin oxidoreductase indicates that there may be subtle differences in the mechanism of the oxidoreductase from different organisms. The key points and contrasts in the mechanism of these enzymes may be summarized as follows. Addition of pyruvate to a stoichiometric amount of enzyme leads to the formation of an equimolar amount of CO2. In H. halobium (213) a enzyme-mediated one-electron transfer to an exogenous electron acceptor occurs at this stage, with formation of a stable enzyme-bound radical intermediate, whereas the enzyme from C. acidiurici remains in the oxidized state. Addition of CoA leads to the subsequent formation of acetyl-CoA from both enzymes, which reduction (two electrons ) of an unknown chromophore in the... 

Stoichiometric experiments were conducted with the functionalized alkenes to further explore iron-substrate interactions and gauge relative coordination affinities. Several bis(imino)pyridine iron amine and ketone compounds were isolated and studied using a combination of X-ray diffraction, NMR and Mossbauer spectroscopy and established electronic structures similar to that for ( PDI)Fe(N2)2-In the absence of H2, diallyl ether and allyl ethyl ether underwent facile C-0 bond cleavage and yielded a near equimolar mixture of the corresponding iron allyl and alkoxide complexes [89]. Our group has recently published a comprehensive study on these types of reachons and discovered rare examples of C-0 bond cleavage in saturated esters [89]. 

Mixing of equimolar solutions of [Cu(CH3CN)4]PF6 in acetonitrile and Zn porphyrin-containing macrocycle 44 [80] in dichloromethane, followed by addition of phenanthroline derivative 45 in dichloromethane afforded in quantitative yield precatenate 48" . Subsequently, this complex was combined with a stoichiometric amount of gold(III) 5,10-di(p-hydroxyphenyl)-15,20-di(3,5-di-fert-butylphenyl)porphyrinate [47] PF6 in DMF. The resulting so-... 

The interaction of chitosan with carboxylic polyacids leads to the formation of an insoluble PEC. Chitosan is insoluble in neutral and basic media, therefore the stoichiometric PEC is usually obtained by mixing equimolar quantities of the polyacid and chitosan hydrochloride. The complex is formed according to the following reaction ... 

Fujiwara and Moritani discovered in 1%7 that when styrene-palladium chloride complex 1 was heated in benzene (2a), toluene (2b) or p-xylene (2c), in the presence of acetic acid, tra 5-stilbene (3a), rram -methylstilbene (3b) or tra -2,5-dimethylstilbene (3c) were produced respectively, albeit in low yields (Equation (9.1)) [3], No stilbene derivative was obtained, however, in the case of mesitylene, which may be attributed to the steric hindrance of three methyl groups on the benzene ring [3]. Shortly thereafter, Fujiwara and coworkers [4] found that arylation of styrene (4a) occurred much more efficiently in the presence of stoichiometric palladium acetate instead of the styrene-palladium chloride complex (1). Thus, equimolar amounts of styrene (4a) and palladium acetate were refluxed in benzene (2a) in the presence of acetic acid, affording a 90% yield of rran -stilbene (3a). In the case of toluene (2b) and p-xylene (2c), fran5-4-methylstilbene (3b, 58%) and rran5-2,5-dimethylstilbene (3c, 47%) were obtained (Equation (9.2)). 

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