An accurate treatment of electrostatic interactions has always been crucial to solving problems of intermolecular interaction, Severe difficulties due to the long-range nature of electrostatic potentials, their many-centred additivity and the interference of solvent and polarisability have continued to plague efforts in this area. Yet such interactions underlie crucial features of molecular systems such as the free energy of solvation, the stabilisation of transition states by the alignment of solvent dipoles, the recognition of ligands by biological receptors and the properties of polymeric materials. For chemists interested in the design of new compounds or in gaining new insights into chemical reactivity, obtaining information about modern advances in the treatment of electrostatics is made difficult by the fragmentation of the subject in the literature. Furthermore, chemists have the option to use a number of commercial software packages in which the electrostatic handling may be very different and hard to ascertain.
In choosing articles for inclusion into this special issue of the Journal of Computer-Aided Molecular Design, the goal has been to illustrate how the nature of the electrostatic modelling problem, and methods for its solution, can be modified according to the total number of atoms in the system. In addition, emphasis has been placed upon the various graphical techniques which are becoming commonplace, especially with the power of modern workstations. The examples illustrating the applications in each paper comprise structures of biological importance, or systems of interest in the study of reactions in the gas-phase and solution. Despite this, the concepts outlined should have wide applicability to problems such as the design of new materials, dyes, catalysts and superconducting ceramics.
In solvents such as water, or DMSO, which possess large molecular dipole moments and high bulk effective dielectric constants, the solvation energy due to the interaction with the monopoles,