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Molecular mechanics (MM3) calculations on lithium amide compounds
Author(s) -
Yoshida Takashi,
Sakakibara Kazuhisa,
Asami Masatoshi,
Chen KuoHsiang,
Lii JennHuei,
Allinger Norman L.
Publication year - 2003
Publication title -
journal of computational chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.907
H-Index - 188
eISSN - 1096-987X
pISSN - 0192-8651
DOI - 10.1002/jcc.10161
Subject(s) - chemistry , lithium (medication) , ab initio , computational chemistry , lithium atom , molecule , amide , ab initio quantum chemistry methods , dipole , force field (fiction) , electronic structure , ion , physics , quantum mechanics , organic chemistry , medicine , ionization , endocrinology
The MM3 force field has been extended to deal with the lithium amide molecules that are widely used as efficient catalysts for stereoselective asymmetric synthesis. The MM3 force field parameters have been determined on the basis of the ab initio MP2/6‐31G* and/or DFT (B3LYP/6‐31G*, B3‐PW91/6‐31G*) geometry optimization calculations. To evaluate the electronic interactions specific to the lithium amides derived from the diamine molecules properly, the Lewis bonding potential term for the interaction between the lithium atom and the nonbonded adjacent electronegative atom such as nitrogen was introduced into the MM3 force field. The bond dipoles were evaluated correctly from the electronic charges on the atoms calculated by fitting to the electrostatic potential at points selected. The MM3 results on the molecular structures, conformational energies, and vibrational spectra show good agreement with those from the quantum mechanical calculations. © 2003 Wiley Periodicals, Inc. J Comput Chem 24: 319–327, 2003