INTEGRATED APPROACH FOR C-13 NUCLEAR-MAGNETIC-RESONANCE SHIFT PREDICTION, SPECTRAL SIMULATION AND LIBRARY SEARCH

A computer approach is developed that permits fast estimation of the C-13 chemical shifts of common organic compounds, spectral simulation of these compounds, and shift/structure search in a user-maintained spectral library. In the first part of this PC-based program (called CSPEC2), the C-13 shifts- are predicted on the basis of empirical additive shift rules, and are applicable to carbons contained in commonly occurring organic functional groups, including olefins, acetylenes, aromatics and carbonyls. Structure input and modification are facilitated and shift accuracy improved through the availability of library compounds and the use of a ''parent structure'' option. The predicted shifts for any compound can be displayed as a printed output, as a file, or as a simulated spectrum. In the second part of the program, partial C-13 shifts, molecular formula, or chemical names can be searched sequentially in the spectral library. The use of this computer program is illustrated by suitable examples. Major advantages of this approach include the ease of use and the ability to modify the additivity shift parameters or to add additional functional groups to the program.