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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. __________ 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). _________ FORTRAN 77 (TR445) Lines of Code: 3208 |