Is the avoided crossing state a good approximation for the transition state of a chemical reaction? An analysis of Menschutkin and ionic SN2 reactions

1994 ◽  
Vol 116 (1) ◽  
pp. 262-273 ◽  
Author(s):  
S. Shaik ◽  
A. Ioffe ◽  
A. C. Reddy ◽  
A. Pross
Keyword(s):  
Transition State ◽  
Chemical Reaction ◽  
Sn2 Reactions ◽  
Avoided Crossing

scholarly journals Protein dynamics and catalysis: the problems of transition state theory and the subtlety of dynamic control

2006 ◽  
Vol 361 (1472) ◽  
pp. 1433-1438 ◽  
Author(s):  
J.R.E.T Pineda ◽  
S.D Schwartz
Keyword(s):  
Lactate Dehydrogenase ◽  
Transition State ◽  
Protein Dynamics ◽  
Chemical Reactions ◽  
Chemical Reaction ◽  
Condensed Phase ◽  
Transition State Theory ◽  
State Theory ◽  
Ongoing Research ◽  
Chemical Catalysis

This manuscript describes ongoing research on the nature of chemical reactions in enzymes. We will investigate how protein dynamics can couple to chemical reaction in an enzyme. We first investigate in some detail why transition state theory cannot fully describe the dynamics of chemical reactions catalysed by enzymes. We describe quantum theories of chemical reaction in condensed phase including studies of how the symmetry of coupled vibrational modes differentially affects reaction dynamics. We make reference to previous work in our group on a variety of condensed phase chemical reactions (liquid and crystalline) and a variety of enzymatically catalysed reactions including the reactions of lactate dehydrogenase and purine nucleoside phosphorylase. All the protein motions we have studied have been quite rapid. We will propose methods to find motions over a broad range of time-scales in enzymes that couple to chemical catalysis. We report recent findings which show that conformational fluctuations in lactate dehydrogenase can strongly affect its ability to catalyse reactions through protein motion, and that only a tiny minority of conformations appear to be catalytically competent.

Investigation of electron density changes at the onset of a chemical reaction using the state-specific dual descriptor from conceptual density functional theory

2015 ◽  
Vol 17 (14) ◽  
pp. 9359-9368 ◽  
Author(s):  
Frank De Proft ◽  
Valérian Forquet ◽  
Benjamin Ourri ◽  
Henry Chermette ◽  
Paul Geerlings ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Transition State ◽  
Linear Combination ◽  
Electron Density ◽  
Chemical Reaction ◽  
Density Functional ◽  
The State ◽  
Dual Descriptor ◽  
Conceptual Density Functional Theory ◽  
Functional Theory

The electron density changes from reactants towards the transition state of a chemical reaction is expressed as a linear combination of the state-specific dual descriptors (SSDD) of the corresponding reactant complexes.

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