Structures and conformational dynamics of trans- and cis-crotonaldehydes in excited electronic states: A quantum-chemical study

• Published in: Computational and theoretical chemistry Vol. 1149; pp. 8 - 16
• Main Authors: Bokareva, O.S., Bataev, V.A., Godunov, I.A.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.02.2019
• Subjects: Crotonaldehyde; Excited states; Internal rotation; Non-rigid molecules; Internal rotation; Non-rigid molecules; Excited states; Crotonaldehyde
• ISSN: 2210-271X
• DOI: 10.1016/j.comptc.2018.11.009

[Display omitted] •Crotonaldehyde in 1,3(n,π*) states have been shown to possess a symmetry plane.•Crotonaldehyde in 1,3(n,π*) states are significantly non-planar.•Couplings of internal rotations with others large amplitude motions can be important in dynamics. For trans- and cis-crotonaldehydes CH3CHCHCHO in the triplet and singlet lowest excited electronic states of n,π* and π,π* types, the geometries of conformers, conformer energy differences, and conformational dynamics have been addressed using ab initio multi-reference techniques (CASSCF and CASPT2). The conformers of investigated molecules under study have been shown to possess a symmetry plane in 1,3(n,π*) states and to be significantly non-planar in 1,3(π,π*) states. Couplings of asymmetric internal rotations around CC and CC bonds with others large amplitude molecular motions such as methyl torsion, non-planar distortions of CCHO, CCHC, and CCH(CH3) fragments are discussed. The type of coupling between large-amplitude motions has been shown to be connected with the localization of electronic excitation.