Strain energy minimization study of the mechanism of, and the barrier to, conformational interconversion in five-membered diamine chelate rings
✍ Scribed by Trevor W. Hambley
- Publisher
- John Wiley and Sons
- Year
- 1987
- Tongue
- English
- Weight
- 671 KB
- Volume
- 8
- Category
- Article
- ISSN
- 0192-8651
No coin nor oath required. For personal study only.
✦ Synopsis
The method of Lagrangian multipliers is used to constrain torsion angles during molecular mechanics refinement for the purpose of plotting strain energy against a reaction coordinate. A complete twodimensional analysis of the conformational interconversion from 6-to A -[Co(ethane-l,2-diamine) (NHd4I3' reveals a mechanism in which the transition state geometry has an envelope conformation and an inversion barrier of 15.7 kJ mol-'. Substitution at the carbon atoms, variation of the metal-nitrogen distance, and replacement of the amine ligands with bidentate amines only slightly alters the inversion barrier. Substitution at the nitrogen atoms of the bidentate ligand increases the inversion barrier significantly to 24.6 kJ mol-' for (N,N,N',N'-tetramethylethane-1,2-diamine) (NH3I4l3'.