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536. JOBO/HAMA: Programs for Calculation of Aromatic
Ring Current Effects
by Gerhard Hägele and Wolfgang Kückelhaus, Institut für
Anorganische Chemie und Strukturchemie I, Universität
Düsseldorf, D-4000 Düsseldorf, FRG
These two computer programs predict shielding
contributions for protons being influenced by the
magnetic anistropy of aromatic ring systems. JOBO, the
first program, is based on the semi-classical theory of
Johnson and Bovey.1 The required data tables, which
have been compiled by Emsley, Feeney and Sutcliffe,2
are implemented in the software. For HAMA, the second
program, the quantum mechanical ring current model of
Haigh and Mallion3,4 has been employed. Both programs
are designed for consistent data input containing the
molecular structure in the form of Cartesian
coordinates. The molecular geometry can be obtained by
molecular mechanics or MNDO calculations. If only x-
ray data are available, JOBO and HAMA convert them to
Cartesian data sets. A detailed input description is
given at the head of the programs. The final output of
JOBO and HAMA yields dia- and paramagnetic shielding
contributions (ppm) where a negative sign implies high
field shift and vice versa. Note that shielding
contributions for methyl protons may be obtained
optionally as averaged values for rigid or rotating
CH3-groups.
Experience has shown that JOBO and HAMA are suitable
tools for NMR studies and for the correlation of NMR
parameters with molecular structures.
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References:
1. C. E. Johnson, Jr., and F. A. Bovey, J. Chem.
Phys., 29, 1012 (1958).
2. J. W. Emsley, J. Feeney and L. H. Sutcliffe, High
Resolution NMR Spectroscopy, Vol. 1 (Oxford:
Pergamon Press), 1965, p. 595.
3. C. W. Haigh and R. B. Mallion, Proc. Nucl. Magn.
Reson. Spectrosc., 13, 303 (1980).
4. C. W. Haigh and R. B. Mallion, Org. Magn. Reson.,
4, 203 (1972).
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FORTRAN 77 (TR445)
Lines of Code: 3208
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