Thermodynamics of Charge Transfer Complexes

Although several physical methods, winch have been listed earlier, may be employed to evaluate the equilibrium constants for complex formation, the spectrophotometric method has been used most often. Following Ketelaar80. the acceptor concentration may be maintained at a constant low value and the extinction coefficients of the complex (c) and donor (m) species followed at various donor concentrations [Dj, by measuring the intensity of the characteristic absorption spectrum of the complex. In such a case, lie optical density d, when corrected for absorption by the donor, at a given wavelength is given by Ketelaar relationship 

If is negligibly small relative to then the Ketelaar equation reduces to 

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Quantitative Evaluation of Arenes as Electron Donors 437 Spectral (UV/vis) Probe for the Formation of CT Complexes 438 IR Spectroscopic Studies of Charge-Transfer Complexation 442 Thermodynamics of Charge-Transfer Complexation 443 Structural Features of Arene Charge-Transfer Complexes 445 Bonding Distance of the Donor/Acceptor Dyad in Arene Complexes 446 Relationship Between Hapticity and Charge Transfer in Arene Complexes 447 Effect of Charge Transfer on the Structural Features of Coordinated Arenes 448... 

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