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Ring inversion in 1,4,7 cyclononatriene and analogues: Ab initio and DFT calculations and topological analysis
Author(s) -
Zamora Miguel A.,
Suvire Fernando D.,
Enriz Ricardo D.
Publication year - 2007
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.20789
Subject(s) - chemistry , ab initio , density functional theory , transition state , ring flip , computational chemistry , conformational isomerism , crystallography , ring (chemistry) , molecule , catalysis , biochemistry , organic chemistry
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 conformational interconversion pathways were analyzed. Altogether, four geometries (two low‐energy conformations and two transition 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 predict that 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 , describing the conformations as well as the conformational interconversion process in these hypersurfaces. © 2007 Wiley Periodicals, Inc. J Comput Chem, 2008