Ring Inversion in 1,4,7 Cyclononatriene and Analogues. Ab initio and DFT calculations and Topological Analysis

M.A.ZAMORA, F.SUVIRE R.D.ENRIZ

JOURNAL OF COMPUTATIONAL CHEMISTRY

Wiley

Año: 2008 vol. 29 p. 280 - 290

0192-8651

Abstract: The multidimensional conformational potential energy hypersurfaces (PEHSs) for cis-cis-cis 1,4,7 cyclononatriene (I), Tribenzocyclononatriene (TBCN) (II), and cis-cis-cis cyclic triglycine (III) were comprehensively investigated at the Hartree–Fock (HF/6-31G(d)) and density functional theory (B3LYP/6-31G(d,p)) levels of theory.The equilibrium structures, their relative stability, and the transition state (TS) structures involved in the conformationalinterconversion pathways were analyzed. Altogether, four geometries (two low-energy conformations and twotransition states) were found to be important for a description of the conformational features of compounds I–III. B3LYP/aug-cc-pvdz//B3lYP/6-31G(d,p) and MP2/6-31G(d,p)//B3LYP/6-31G(d,p) single point calculations predictthat the conformational interconversion between crown and twist forms requires 14.01, 26.71, and 17.79 kcal/mol. For compounds I, II, and III, respectively, which is in agreement with the available experimental data. A topological study of the conformational PEHSs of compounds I–III was performed. Our results allow us to form a concise idea about the internal intricacies of the PEHSs of compounds I–III,