Complexation entropy

The enthalpies of complexation of 3.8c to the copper(lf) - amino acid ligand complexes have been calculated from the values of at 20 C, 25 1C, 30 1C, 40 1C and 50 1C using the van t Hoff equation. Complexation entropies have been calculated from the corresponding Gibbs energies and enhalpies. 

It would appear that the tradeoffs between these two requirements are optimized at the phase transition. Langton also cites a very similar relationship found by Crutchfield [crutch90] between a measure of machine complexity and the (per-symbol) entropy for the logistic map. The fact that the complexity/entropy relationship is so similar between two different classes of dynamical systems in turn suggests that what we are observing may be of fundamental importance complexity generically increases with randomness up until a phase transition is reached, beyond which further increases in randomness decrease complexity. We will have many occasions to return to this basic idea. 

For molecules of similar mass and complexity, entropies are larger for gases than for liquids than for solids. 

W. H. Zurek, ed. 1990. Complexity, Entropy, and the Physics of Information. North Reading, MA Addison Wesley. 

Even if similar primary hydrogen-bond strengths are found in these complexes, such a correlation is surprising because it seemingly requires a linear correlation between the complexation entropy and the number of... 

Bennett CH How to define complexity in physics, and why. In Complexity, Entropy and the Physics of Information. Edited by Zurek WH. Redwood City California Publisher Addison-Wesley 1990 137—148. 

The main difficulty in calculating this value normally lies in the determination of the activated complex entropy. 

The increased strain in chelation with ring expansion is also reflected in the complexation entropy. The dependence of the entropy ehange for the overall reaction. 

It is given from table 1, that an activation free energies, activation enthalpies, activation entropies and pre-exponential factors are satisfactory compared with experimental ones. Complex activation entropy is increasing, but that factor is not contradicted with well-known ideas. Changing is occurred with increasing of vibration part of active complex entropy. Rotation part of active complex entropy is changed lightly (table 2). 

J.G. Roederer On the Concept ofinformation and its Role in Nature Entropy 5(2003)1 and in W.H. Zurek (Rd.) Complexity, Entropy and the Physics ofinformation Addison-Wesley, New York 1990... 

A calorimetric study revealed the thermodynamic characteristics for the formation of complex 9 in the various solvents [9,23]. The formation of 9 is enthalpically driven in all solvents, and complexation entropies are mostly unfavorable. Complexation in protic solvents exhibits die largest exothermicity and, in general, die enthalpic driving force decreases fiom polar protic, to dipolar aprotic, and to apolar solvents. Correspondingly, the complexation entropy becomes increasingly less favorable as the exothermicity increases, resulting in a strong isoequilibrium relationship. 

The same kind of experiment can be repeated with CCI4 as the solvent. The result, AH° = -31.88 kJ moH shows that the transfer of the reagents and product from cyclohexane to CCI4 is accompanied by a complexation enthalpy change of +2.37 kJ mol Since the complexation entropy change from cyclohexane to CCU is also positive (+7.1 J moH ), on the whole the hydrogen-bond basicity of cyclopropylamine is less sensitive to the solvent change than its affinity. 

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