Intermolecular complexation energies

Jeziorski B, Moszynski R and Szalewicz K 1994 Perturbation theory approach to intermolecular potential energy surfaces of van der Waals complexes Chem. Rev. 94 1887... 

The next important phenomena that the result of supramolecular effect are the concentration and proximity effects concerning the components of analytical reaction, even through they are considerably different in hydrophobicity, charge of the species, complexing or collisional type of interaction. The concentration and proximity effects determine the equilibrium of analytical reaction, the efficiencies of intramolecular or intermolecular electronic energy or electron transfer and as a result the sensitivity of analytical reactions. 

In reviewing the performance of density functional theory applied to hydrogen bonded complexes of moderate strength, we repeatedly noted a systematic underestimation of the interaction energies for many types of functionals, usually below 2 kcal/mol. This has been related by some researchers to the inability of modem functionals to describe those contributions to intermolecular binding energies which stem from dispersion forces. Dispersion... 

Gresh N, Piquemal J-P, Krauss M (2005) Representation of Zn(II) complexes in polarizable molecular mechanics. Further refinements of the electrostatic and short-range contribution of the intermolecular interaction energy. Comparisons with parallel ab initio computations. J Comput Chem 26 1113... 

A dynamical model for SN2 nucleophilic substitution that emerges from the trajectory simulations is depicted in Figure 9. The complex formed by a collision between the reactants is an intermolecular complex CinterR. To cross the central barrier, this complex has to undergo a unimolecular transition in which energy is... 

Molecular modeling calculations may allow one, in the ideal case, to compute in a reasonable time and rather precisely the energy and structure of intermolecular complexes of biomedical, pharmaceutical, and chemical relevance. 

Biesheuvel, P.M., Cohen Stuart, M.A. (2004). Electrostatic free energy of weakly charged macromolecules in solution and intermolecular complexes consisting of oppositely charged polymers. Langmuir, 20, 2785-2791. 

A problem with DFT that is not restricted to intermolecular complexes is what might be called overdelocalization . In part because of problems in correcting for the classical self-interaction energy, many functionals overstabilize systems having more highly delocalized densities over more localized alternatives. Such an imbalance can lead to erroneous predictions of higher symmetry structures being preferred over lower symmetry ones, as has been observed, for instance, for phosphoranyl radical structures (Lim et al. 1996), transition-state structures for cationic [4-1-3] cycloadditions (Cramer and Barrows 1998), and in the comparison of cumulenes to poly-ynes (Woodcock, Schaefer, and Schreiner 2002). It can... 

Within the supermolecular approach, the total intermolecular interaction energy (AE) of a complex A---B is evaluated as the difference between the energy of the complex (EA" B) and the sum of the energies of its subsystems (EA, EB) ... 

Because of the efficiency, the density functional theory also became an object of interest for the purpose of evaluation of intermolecular interaction energies for nucleic acid base complexes. Most standard functionals provide qualitatively a good picture of interactions in H-bonded nucleic acid base pairs. However, they completely fail for stacked complexes. This is due to the inability of current functionals to describe correctly the dispersion energy. Several routes were proposed to alleviate this deficiency with different rates of success [9-12],... 

Fig. 20.1 The average, the maximal and the minimal values of intermolecular interaction energy for stacked nucleic acid base complexes calculated at the MP2/aug-cc-pVDZ level of theory...

Fig. 20.3 The total intermolecular interaction energy and the first-order electrostatic interaction for 54 structures of guanine-adenine complex...

A priori, this situation could be ascribed to two principal factors (a) the greater intrinsic stability of the form N(7)H (b) the higher value of the crystal packing forces in the case of the N(7)H form, a complex problem which may perhaps be simplified by comparing the intermolecular interaction energies in the dimer (86) with those in the hypothetical dimer (87), which differs from 86 only in the shift of the proton from N-7 to N-9 of the bases involved. 

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