Prediction of three-dimensional molecular structures using information from infrared spectra

A method has been developed for obtaining the three-dimensional (3D) struct ure of a molecule directly from the information in an infrared spectrum. By training a counterpropagation network with coded 3D structures and IR spec tra it is possible to simulate the structure code of a query spectrum. To o btain an initial structure, the simulated code is compared with structure c odes generated from a database of over 100,000 molecules. The molecule with the most similar structure code defines die so-called initial model for th e 3D structure. By means of stochastic methods, this initial structure is m odified in various ways to gain the best similarity with the structure code from the neural network. Thus, information from infrared spectra can be us ed to generate the corresponding 3D structure. The scopes and limitations o f the method will be discussed with different examples of compounds using e xperimental IR spectra from various applications. The intention of this met hod is to assist in the interpretation of IR spectra and in structure eluci dation in routine analysis. (C) 2000 Elsevier Science B.V. All rights reser ved.