Competitive ratio

The kg value was determined to be about 6.9 x 10" s independent of the nature of L in 50°C decalin (AH - 31.8 kcal mol-1 AS - +20.2 cal mol 1 K l). Competition ratios k.g/ky equal to 3 and 5 were determined for L - P(OPh3)3 and PPI13, respectively under the same conditions. The second order pathway was proposed to occur via nucleophilic attack of L on the cluster, and an intermediate with a formulation the same as II/ was suggested, without supporting evidence of its existence, as a possible initial product of this nucleophilic attack. However, since fragmentation was only a minor side reaction of the substitution reactions with L - PPI13, it is quite unlikely that the photofragmentation and second order thermal substitution reactions occur via a common intermediate. 

If a series of complexes of different charges and X groups are hydrolyzed in the presence of a constant concentration of (Y-Z) " then a constant competition ratio... 

This is the optical density plotted against the time for an experiment in which we took the nitratopentamminecobalt complex in the presence of 0.50M thiocyanate ion since the competition ratio for thiocyanate ion and for water had been determined by Haim and Taube. Knowing the optical densities of all the possible reactants and products, we could calculate what the optical density should be as a function of time according to the mechanism of Haim and Taube. This calculation depends upon a rate constant for the aquation of the nitrato complex which we took from the literature. But one should get a continuously increasing optical density because the thiocyanate complex has a higher optical density than anything else. 

Dr. Pearson presented data on the optical density observed when the nitrato-cobaltic complex reacts with thiocyanate ion, and there is nothing to object to in these results. But I think one might be concerned about the theoretical curve calculated using the competition ratio in a table wrhich Haim and Taube presented in the journal. 

R. B. Jordan, having learned about the work of Pearson and Moore, has become interested in the issues and has searched for the formation of (NHs CoBr1"2 when (NH3)5CoX03+2 reacts in the presence of Br ". His observations suggest that the bromo complex does appear initially, but on calculating the competition ratio finds it to be less by a factor of about 2 than that reported by Haim and myself. Jordan has done only a single experiment on this. The subject is obviously worth going into in some detail, but at this point I am neither prepared to say that Jordan s result supports the conclusions which Dr. Haim and I reached, nor that it does not. 

It can easily be shown that integration of Eq. (5) affords a linear relationship between log CA and log CB with slope, or competition ratio,/ , as the multiple of constants within the square brackets. The ratio of Langmuir coefficients is obviously coupled with ratios of rate constants and alkyl reversal equilibrium constants. On the other hand, if alkyl reversal is very slow such that fc 3 k4 0H, then Eq. (4) reduces to... 

ECE mechanism (Parker, 1969a see p. 25). In this particular case, a series of benzylic cations were found to show anomalous reactivities, in that the less reactive ones were selective toward the weaker nucleophile, acetonitrile, contrary to predictions based on concepts from homogeneous solution chemistry.1 2 Moreover, in a certain region of water concentrations the competition ratio between the... 

Figure 5. Plot of the logarithm of the competition ratio (ratio of products formed via trapping by acetonitrile and water, respectively) versus percentage water in the solution. Filled circles, p-xylene open circles, o-xylene triangles, hexamethylbenzene. Solid lines, electrochemical reaction broken lines, solvolysis of ArCHjOTs.

Relative ratio of product (target) to housekeeping gene or other heterologous dsDNA internal standard Competitive ratio of product (target) to homologous, modified internal standard (competitor) most accurate estimate Applications... 

When NBE and NBD are copolymerized by I the competition ratio is exactly 1.0 showing these monomers compete equally in propagation. However the diene initiates about ten times more efficiently than the monoene and this is also the ratio of the intensities of the epr triplet signals. 

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