Reaction ordinate, definition

Accordingly, the search for unambiguous data leads to studies of kinetically inert octahedral metal complexes or pyridine, bpy and phen, which are not expected to form seven co-ordinate products. There have been numerous studies of [M(bpy)3]"+ and [M(phen)3]"+ complexes, but it is probably fair to state that no definitive evidence for activation towards attack of hydroxide at the ligand has been presented. There is no doubt, however, that sufficient kinetic anomalies exist for further study to be worthwhile, and the importance of [M(bpy)3]"+ and [M(phen)3]"+ complexes in photocatalytic systems should justify this. A possible chemical consequence of the reaction of a nucleophile with a co-ordinated heterocycle is seen in the reaction of (2,2 - bipyrimidinejruthenium(11) and hydroxide ... 

Klippenstein and colleagues calculated rate constants for these barrierless reactions employing a method they termed variational reaction co-ordinate transition state theory (VRC-TST). In this version of TST, variational does not only refer to the procedure for finding the location of the transition state along the reaction co-ordinate, for each combination of energy (E) and total angular momentum (J), but also to a search for the optimum definition of the... 

In the quantal method, the explicit introduction of electron translation factors is inconvenient and it has proved more appropriate to introduce some suitable system of reaction co-ordinates (Mittleman, 1969 Thorson and Delos, 1978 Delos, 1981 Soloviev and Vinitsky, 1985) which modifies the definition of the adiabatic states so that the asymptotic conditions of the collision are automatically accounted for. Since the method is not yet standard, a description of its essential features will be presented in section 3. 

Definitive kinetic evidence that the reaction of the five-co-ordinate model complex (10 R=H) with CO follows a direct association mechanism (33) has been described... 

The kinetics of the reaction between peroxomonosulphate and thiocyanate were earlier interpreted in terms of the intermediate of species such as HS(0)CN, (SCN)a, and HO(SO)CN. No definite proof of this is available, but the detection of similar intermediates, RSO2CN and R(SO)CN, in reactions between alkyl thiocyanates and peroxomonosulphate lends support to the intermediacy of HS(0)CN and HO(SO)CN in the peroxomonosulphate-thiocyanate reaction.The kinetics of decomposition of the iV-nitroso-hydroxylamine-A -sulphonate anion to sulphate and nitrous oxide have already been described under nitrogen. The mechanism of substitution at sulphur(iv) in sulphinyl compounds, RS(0)Y, is still a topic of unresolved discussion, despite much effort in this area. The question awaiting answer is whether the mechanism is simple Ssl or whether there is a four-co-ordinate intermediate of significant lifetime. > Though the determination of Bronsted coefficients did not provide definite mechanistic evidence relating to substitution at... 

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