Expert systems as a tool for the molecular structure elucidation by spectral methods. Strategies of solution to the problems

Abstract

A great number of spectral tasks were solved to elaborate strategies of molecular structure elucidation by expert systems based on the spectrum-structure correlations. The X-PERT system was used for this purpose. The main assumptions of the structural-group spectral analysis and the main consequences of their violation are considered. The typical difficult situations met with, while problem solving, are investigated. A method for quality estimation of solutions to spectrum-structure problems is suggested. The capacity of 13C NMR chemical shift prediction by the additivity rules for selection the true structure was verified. Strategies of the solution to a problem are suggested. The main feature of the offered approach is in a series of reiterations accompanied by gradual growth of severity of the constraints which are imposed on the answer structural file. It is concluded that X-PERT can be successfully used for the structure elucidation of medium-sized molecules as well as for teaching spectral methods to students.