Analog experiments

The vibrationally excited states of H2-OH have enough energy to decay either to H2 and OH or to cross the barrier to reaction. Time-dependent experiments have been carried out to monitor the non-reactive decay (to H2 + OH), which occurs on a timescale of microseconds for H2-OH but nanoseconds for D2-OH [52, 58]. Analogous experiments have also been carried out for complexes in which the H2 vibration is excited [59]. The reactive decay products have not yet been detected, but it is probably only a matter of time. Even if it proves impossible for H2-OH, there are plenty of other pre-reactive complexes that can be produced. There is little doubt that the spectroscopy of such species will be a rich source of infonnation on reactive potential energy surfaces in the fairly near future. 

It has been observed that the H-Si(lll) and H -Si(lOO) surfaces develop a submonolayer oxide when exposed to an average sitting time of 1 h prior to gate oxidation in typical room air and room lighting conditions. Furthermore, the oxidation of the H-Si(lll) and H3.-Si(100) surfaces occurs when they are exposed to UV light in the presence of dry air or humid air. Analogous experiments are reported for the photo-oxidation of pSi. ... 

For molecular catalytic systems, it is remarkable to note that the conversion at short times (< 5 h), increases with increasing Pd/substrate ratio. Actually, the nanoclusters formation seems to be less probable, in contrast to analogous experiments carried out for other Pd-cata-lysed reactions like C-C Fleck couplings [58]. 

Analogous experiments using electrons instead of photons have been carried out with the same results. Electrons passing through a system with double slits produce an interference pattern. If a detector determines through which slit each electron passes, then the interference pattern is not observed. As with the photon, the electron exhibits both wave-like and particle-like behavior and its location on a detection screen is randomly determined by a probability distribution. 

Note that similar dependence was observed in analogous experiments for hydrogen atoms produced in the discharge [59]. In this work the dependence determined by the SCS technique was compared with the... 

The analogous experiment with 1-pentene also yields a single product as indicated in Table IV. In addition, the product, in which ethylene is eliminated, is different from that observed in the case of 2-pentene In this case, the process with the lowest activation energy does not correspond to the most exothermic process (Table IV). Again the process of lowest energy involves cleavage of the allylic C-C bond in preference to the allylic C-H... 

Diehn and Kint115) and Mikolajczyk and Diehn71) demonstrated specific inhibition of photoaccumulation and of the step-down photophobic response of Euglena gracilis, respectively, by potassium iodide. Iodide ions are known to de-excite flavins, but do not affect carotenoids87). For a description of the analogous experiments with corn coleoptiles, see Sect. 3.2 of the contribution by Schmidt in this volume. 

These systems have been successfully applied as catalyst media for the biphasic, Rh-catalysed hydroformylation of 1-octene [11], [62]. The catalyst activities obtained with these systems were in all cases equal or even higher than those with the commonly used [BMIM][PF6]. Table 7.4 compares some typical results using Rh-sulfoxantphos in alkylsulfate and sulfonate ionic liquids with analogous experiments in a hexafluorophosphate system. 

No bromine ion is liberated when the analogous experiment is performed with bromobenzene (next preparation). Distinction between halogen in aliphatic and aromatic combination. 

The addition of stoichiometric amounts of Ni2+, Cu2+ and Zn2+ to solutions of [28]—[32] in acetonitrile led to large anodic shifts of the respective ferrocene/ferrocenium redox couple of up to 190 mV in the case of [29] and Cu2+ (Table 8). Analogous experiments in water at pH values 10.5-12 revealed that [28]—[32] electrochemically recognize these transition metal cations in the aqueous environment (Table 9). 

Their studies involved the partial polymerization of NCAs of mixtures of specific amino adds having known e.e.s, followed by determination of the e.e.s of the amino adds in both the resulting polypeptides and in the residual unreacted NCA monomers. [94] In a typical experiment it was found that when an optically impure leucine NCA monomer having an l > d e.e. of 31.2% was polymerized to the extent of 52 % to the helical polyleucine peptide, the e.e. of the polymer was enhanced to 45.4 %, an increase of 14.2 %. In the same experiment the e.e. of the unreacted leucine NCA monomer was depleted to a similar extent. Analogous experiments with valine NCAs of known e.e.s, however, led to a reverse effect, namely, the preferential incorporation of the racemate rather than one enantiomer into the growing polyvaline peptide. This finding was interpreted to be the result of the fact that polyvaline consists of (3-sheets rather than a-helices, emphasizing that the Wald mechanism applies only to a-helix polymers. At about the same time Brach and Spach [95] showed that, under proper conditions, (3-sheet polymers could also be implicated in the amplification of amino add e.e.s. 

Analogous experiments and analyzing procedures on MeLPPP in dilute... 

Racemic aldehyde 2 under similar reaction conditions yielded two diastereo-meric pinacols the configuration of all the products was assigned by X-ray diffraction. On the basis of these results a mechanistic scheme could be proposed to explain the stereochemical course of the coupling reactions [19]. It is assumed that the reaction proceeds via an intermediate titanaoxirane by insertion of a molecule of aldehyde 2 into the Ti—C bond - a proposal that has been put forward recently on the basis of DFT calculations [20]. The pinacol-type coupling products could be employed as bidentate P,P chelate ligands to Mo(CO)4 fragments however analogous experiments carried out with the olefinic derivatives 18 were unsuccessful [19]. 

Franke and Schumacher61 subsequently performed the analogous experiment in the gas phase with CCl3Br and either Br2 or Cl2 in the presence of 02. The reaction scheme was... 

CF2Cl)2CO and CFC]2C0CF2C1 and in the electrical discharge103 of fluorocarbons. In the presence of a large excess of 02 there was no evidence for BrO radicals in contrast to analogous experiments with CCl2Br2. Furthermore, the CF2 concentration was independent of the 02 pressure. Simons and Yarwood concluded that the primary process was... 

An analogous experiment was run by the same group to study the bioconversion of nerol. It was degraded in essentially the same way as geraniol. Identical products as from geraniol were recovered as major metabolites, together with neral and neric acid [37]. 

We consider now the analogous experiments under the condition of [S] less than Km, as in Figure 12.3. Here the Gibbs free energy of ES is greater than that of E + S, and the reaction rate is v = ( cat/7 M)[E]0[S]. Under this condition, both the... 

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