Use of crystallographic data in searching for isosteric replacements: Composite crystal‐field environments of nitro and carbonyl groups

摘要

AbstractOver 70 000 organo‐carbon crystal structures are available in the public domain. A common functional group may occur in several hundred of these structures. Examination of the immediate intermolecular environment of a functional group in each of the structures in which it occurs enables a composite crystal‐field environment to be determined. Although influenced by random packing forces, the composite environment may show strong systematic features which reflect the preferred interactions of the functional group. This is shown by test calculations on structures containing nitro and carbonyl groups, using in‐house software. Strong systematic features exist in the composite environments of both groups, showing their tendency to hydrogen bond in approximately the directions of the oxygen lone pairs, and to participate in strong electrostatic interactions in the direction normal to the plane of the group. Such results are of value in aiding the search for bioisos