FRAGMENT DATA BASE
INTERCHEM and INTERCHEM-PC make use of the same set of fragment structures in their facilities for building structures. There are ~400 structures in the data base; some of these are optimized structures of real molecules; others are structures of functional groups that have no separate existence. Joining together a pair of these fragments along defined bond directions, with the elimination of a pair of atoms (usually hydrogens, one from each fragment) is a reliable way of obtaining a composite structure of defined stereochemistry. The building process in both of the programs allows the joining process to be used repeatedly, to get complex structures. Final optimisation using Molecular Mechanics (ICMECH) and/or semi-empirical programs (MOPAC) gives reliable and realistic structures.
Revised 18th June 2007