Stephen R. Heller
Richard J. Feldmann
National Institutes of Health
Bethesda, Maryland 20014
A computer program has been developed to rapidly search for spectra containing specified chemical
shifts from proton nmr spectral data. A number of chemical shift correlation charts have appeared over
the years in both the literature and in nmr textbooks (1). One goal of these charts was to enable the student
to "get a feeling" and aid in interpretation and structural elucidation of compounds. These charts indicated
what chemical group might be giving rise to a peak or group of peaks.
The results of the search program are the Varian catalog numbers since the three digit numbers save
computer storage space relative to the length of chemical names (which are not given for many
compounds in the file) and the search is designed to be used interactively by the student. It is hoped that
the student would sit down at the computer, with catalogs in hand, and interact. The data base used for
the search consists of the two Varian spectra catalog (2) which contain proton nmr spectral data on 742
compounds. Only chemical shifts and not coupling constants were used. The chemical shifts had already
been assigned in the catalog and it was felt that it would not be possible to extract accurate coupling
constants from the spectra in the catalog. About 2800 chemical shifts and their corresponding catalog
number references were put into computer readable form. Owing to the variation of chemical shift with
temperature, calibration and solvent (to name a few obvious ones) it was felt that a deviation of +0.02
ppm should be included in a search. Therefore the chemical shift of 2.33 ppm will be found in the range
of 2.31-2.35 ppm.
The search program accepts chemical shifts in ppm as floating point numbers (with a 0 in front of the
decimal point to instill a habit of proper formulation of numeric data). The program cheeks to see if the
shift is properly formatted and automatically performs the Boolean logic AND operation on the shifts and
determines the number of spectra, if any, that contain the combination of chemical shifts inputted into the
program. While the data base is certainly limited, it does contain a large variety of groups and should be
of value, in particular, to users with little experience in the interpretation of nmr spectra.
The file generation and file search programs are written in FORTRAN-IV, with the system presently
running on a DEC-PDP-10-time sharing computer, and require 13K and 16K of core to run, respectively.
Requests for copies of the program should be addressed to Dr. A. W. Pratt, Director, DCRT, NIH,
Bethesda, Md. 20014.
(1) Tiers,, G. V. D., 3M Co., St. Paul, Minn, 1958.
Chamberlain, N. F., Anal. Chem., 31, 56 (1959)
Dietrich, M. W., and Keller, R. E., Anal. Chem., 36, 258 (1964)
Slomp, G.,and Linberg J. G., Anal. Chem., 39, 69 (1967)
Chamberlain, N. F., Anal. Chew., 40, 1317 (1968)
Emsley, J. W., Feeney, J., and Sutcliffe, L. H., High Resolution Nuclear Magnetic Resonance