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Conformational analysis of cycloheptane, oxacycloheptane, 1,2‐dioxacycloheptane, 1,3‐dioxacycloheptane, and 1,4‐dioxacycloheptane
Author(s) -
Freeman Fillmore,
Hwang Jung H.,
Hae Junge Eun,
Dinesh Parmar Prem,
Renz Zhongwei,
Trinh James
Publication year - 2007
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/qua.21486
Subject(s) - conformational isomerism , pseudorotation , cycloheptane , twist , chemistry , computational chemistry , crystallography , molecule , ring (chemistry) , mathematics , geometry , organic chemistry
The conformational analysis of cycloheptane (1), oxacycloheptane (2), 1,2‐dioxacycloheptane (3), 1,3‐dioxacycloheptane (4), and 1,4‐dioxacycloheptane (5) has been carried out using B3LYP, CCD, CCSD, and QCISD with the 6‐311+G(d,p) and cc‐pVDZ basis sets. The twist chair conformers are predicted to be lower in energy than their corresponding boat and chair conformations. All levels of theory predict (4) to be lower in energy than (3) and (5). CCSD predicts remarkably similar activation barriers for the conformational interconversion of the twist chair conformers to their corresponding boat conformers. Small barriers to pseudorotation are also predicted. © 2007 Wiley Periodicals, Inc. Int J Quantum Chem, 2008