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DOI: 10.1055/s-2002-19742
The Chemistry of Intermolecular Bonding: Organic Crystals, their Structures and Transformations
Publikationsverlauf
Publikationsdatum:
02. Februar 2007 (online)
Abstract
The rationalization, prediction and control of structure and properties of organic condensed phases - crystals, liquids, mesophases, and solutions - is a frontier problem in chemistry, made difficult by the relative weakness and scarce directional selectivity of intermolecular bonding. A survey is given of the present status of theories of molecular recognition and of methods for the computer simulation of intermolecular interactions. The organic crystalline state is first considered: lattice energies; polymorphism and crystal chirality; the possibility of prediction of crystalline structure from molecular structure. Some account is then given of evolutionary modeling schemes, those involving a full dynamic simulation of the transformations of chemical systems: crystal melting; molecular aggregation from solutions into micelles and nuclei. As a perspective for years to come, it appears that molecular dynamics in the classical approximation with empirical potentials will be the method of choice in organic physical and theoretical chemistry.
Key words
molecular simulation - molecular recognition - crystal nucleation - crystal structure prediction
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For crystals, where molecules come very close to one another, the dipolar approximation to intermolecular potentials is unsatisfactory because the assumption that intermolecular distances be much larger than dipole dimensions is not valid. For similar reasons, dipole moments for very large molecules (e.g. proteins) are meaningless.
17See ref. [13] Thermochemical measurements are needed for comparisons, but thermochemistry does not really appeal to funding agencies. A research proposal entitled ‘Accurate Thermochemical Measurements on Organic Crystals’ admittedly appeals much less than something like ‘Crystal Engineering of Nano-chemical Systems for Supramolecular Devices and Materials’.
27A related technique is called Monte Carlo simulation: phase space is sampled by random changes in molecular positions and momenta, rather than by trajectories. MD has a more appealing kinetic flavor, though.
31See the references to the experimental work in the discussion in ref. [30]