Free energy perturbations equilibrium constants

The constant kg is the force constant along q and D is the experimental free energy of activation of the reference molecule kgg is an anharmonicity constant, obtained as -kg/ 3q ) from the condition dV/dq = 0 for q = q. A sufficiently small value of a will not change the general appearance of the reaction coordinate for a perturbed molecule, the new equilibrium will be shifted to e(a) and the transition state to q (a), whose magnitudes increase and decrease, respectively. 

The important experimentally accessible parameters are reaction rate constants (A et), activation free energies (proportional to RT In(ket)), equilibrium constants of reactions and/or electrochemical potentials of the component couples, and electron transfer absorption (or emission) energies (e.g., /zi abs in Figure 1), fine structure and bandwidths. The perturbations of these parameters by temperature variations, magnetic or electric fields and isotopic substitution can also provide relevant information. The experimental procedures used to evaluate these parameters are not the focus of this chapter. There are many sources dealing with generaF or specific " techniques. 

The experiments described above have led to the conclusion that the chiral-induced equilibrium shift could be induced in the lanthanide (III) complex by a combination of electrostatic and hydrophobic interactions. Hydrogen bonding effects appear to be less important as suggested by experiments carried out under variable pH, temperature, concentration, solvent type, and solution dielectric constant conditions. By analogy to the associated/dissociated equilibrium shift models of Schipper (1978) in which the source of the equilibrium perturbation is attributed to a free energy of mixing, Brittain (1981) and Wu et al. (1989) attempted to ascertain the complex mechanism responsible for this type of Pfeiffer effect. However, their conclusions were opposite as they concluded that the [Tb(DPA)3] complex interacted with the... 

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