Abstract
The conformations of 2-cyclopenten-1-ol (2CPOL) have been investigated by high-level theoretical computations and infrared spectroscopy. The six conformational minima correspond to specific values of the ring-puckering and OH internal rotation coordinates. The conformation with the lowest energy possesses intramolecular π-type hydrogen bonding. A second conformer with weaker hydrogen bonding has somewhat higher energy. Ab initio coupled-cluster theory with single and double excitations (CCSD) was used with the cc-pVTZ (triple-ζ) basis set to calculate the two-dimensional potential energy surface (PES) governing the conformational dynamics along the ring-puckering and internal rotation coordinates. The two conformers with the hydrogen bonding lie about 300 cm−1 (0.8 kcal/mole) lower in energy than the other four conformers. The lowest energy conformation has a calculated distance of 2.68 Å from the hydrogen atom on the OH group to the middle of the C=C double bond. For the other conformers, this distance is at least 0.3 Å longer. The infrared spectrum in the O-H stretching region agrees well with the predicted frequency differences between the conformers and shows the conformers with the hydrogen bonding to have the lowest values. The infrared spectra in other regions arise mostly from the two hydrogen-bonded species.
Highlights
Our research group has focused on utilizing both experiment and theory to develop a more comprehensive understanding of one-dimensional vibrational potential energy functions (PEFs) and two-dimensional potential energy surfaces (PESs) [1,2,3,4,5,6,7]
We have investigated the PEFs and PESs which govern the conformational dynamics of small ring molecules as well as those governing internal rotations
Each of these molecules can exist as several different conformers which are determined by specific coordinate values of the internal rotations of the OH groups and/or the out-ofplane ring bending modes
Summary
Our research group has focused on utilizing both experiment and theory to develop a more comprehensive understanding of one-dimensional vibrational potential energy functions (PEFs) and two-dimensional potential energy surfaces (PESs) [1,2,3,4,5,6,7]. Each of these molecules can exist as several different conformers which are determined by specific coordinate values of the internal rotations of the OH groups and/or the out-ofplane ring bending modes (ring-puckering or ring-twisting). For each of these molecules, the conformer with the intramolecular π-type hydrogen bonding has the lowest energy, and the π bonding stabilizations range from about 2 to 10 kJ/mol. We wished to investigate the two-dimensional potential energy surface (PES) that governs the conformational changes
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
