Repository: Freie Universität Berlin, Math Department

On the Light-Driven Isomerization of a Model Asymmetric Molecular Rotor: Conformations and Conical Intersections of 2-Cyclopentylidene-tetrahydrofuran

Assmann, M. and Pérez-Hernández, G. and González, L. (2010) On the Light-Driven Isomerization of a Model Asymmetric Molecular Rotor: Conformations and Conical Intersections of 2-Cyclopentylidene-tetrahydrofuran. The Journal of Physical Chemistry A, 114 (34). pp. 9342-9348. ISSN 1089-5639

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Official URL: http://dx.doi.org/10.1021/jp104898t

Abstract

The ground state potential energy surface of the model molecular rotor 2-cyclopentylidene-tetrahydrofuran (CPTHF) has been characterized by calculating minimum energy conformations, racemization pathways, and rotational barriers with high level ab initio electronic structure calculations. Two conformers with their corresponding enantiomers are found. The activation barriers for racemization are negligible, therefore thermal racemization takes place at room temperature. Torsional transition states, calculated using multiconfigurational CASSCF calculations, show twisted and pyramidalized biradical structures. Additionally, the photochemistry of CPTHF has been investigated using the accurate MS-CASPT2/CASSCF methodology. In the UV spectrum it is found that the spectroscopic state is the S1, which corresponds to a ππ* transition within the ethylene moiety. To understand light-triggered isomerization around the C═C bond, five conical intersections between the S0 and S1 have been located for each conformer of CPTHF, which allow the system to rapidly decay to the electronic ground state.

Item Type:Article
Subjects:Physical Sciences > Chemistry > Physical Chemistry
ID Code:1230
Deposited By: BioComp Admin
Deposited On:11 Apr 2013 11:25
Last Modified:19 Apr 2013 10:17

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