USING MOLECULAR GRAPHICS, MOLECULAR MECHA NICS, QUANTUM-CHEMISTRY ANDELECTROSTATIC POTENTIAL METHOD TO STUDY STRUCTURE-PROPERTY RELATIONSHIP ON PESTICIDES .10. STUDY ON INTERNAL-ROTATION PASSAGE IN SULFONYLUREA MOLECULE BY MOLECULAR MECHANICS METHOD
Al. Liu et al., USING MOLECULAR GRAPHICS, MOLECULAR MECHA NICS, QUANTUM-CHEMISTRY ANDELECTROSTATIC POTENTIAL METHOD TO STUDY STRUCTURE-PROPERTY RELATIONSHIP ON PESTICIDES .10. STUDY ON INTERNAL-ROTATION PASSAGE IN SULFONYLUREA MOLECULE BY MOLECULAR MECHANICS METHOD, Gaodeng xuexiao huaxue xuebao, 18(4), 1997, pp. 574-576
In this paper, we have discussed the internal rotation in sulfonylurea
molecules, which belong to high active and low toxic herbicides and t
ake the form of conformational isomers in their crystal structures. In
order to understand the formation of their enantimers, we obtained a
series of data of molecular energy of different conformation by using
the molecular mechanics method and the stepwise rotation single-bond m
ethod. We found out the lowest internal rotation passage and obtained
the energy barrier of hindered rotation which is less 60 kJ/mol. This
result shows that there is a lower energy passage to exchange the conf
ormational isomers of these molecules, so exchanging the different con
formational isomers is not very difficult.