A Computer-Based Chemical Information System

Abstract

To build a chemical information system a data base that can be used in each component must first be located or generated. Then programs for interactive searching of the data bases must be written that will permit the interrogation of a disk-stored data base so that information may be retrieved at low cost. The NIH-EPA [National Institute of Health-Environmental Protection Agency] Chemical Information System (CIS) consists of a series of PDP10-resident numerical and bibliographic data bases together with a battery of interactive, conversational computer programs that can be used to search for and retrieve information from any of the data bases. The data bases which comprise the CIS include mass spectra, 13C-NMR spectra, X-ray diffraction data for organic and inorganic molecules, and X-ray powder diffraction patterns. All of these files can be searched structurally (i.e., they can be examined for the presence of a given chemical structure or substructure). There are 3 biblographic files which contain the literature citations on mass spectrometry, X-ray diffraction of organic molecules and gas-phase proton affinities. The analytical programs that are available can accomplish the iterative analysis of complex NMR spectra, general curve-fitting and linear regression analysis. Other programs can be used to calculate isotopic enrichment from mass spectral data or, for a given species in solution, to find the molecular conformation with the lowest energy.