Theoretical study on the dual fluorescence of 2-(4-cyanophenyl)-N,N-dimethylaminoethane and its deactivation pathway

Xing Chen; Yi Zhao; Zexing Cao

doi:10.1063/1.3112402

Theoretical study on the dual fluorescence of 2-(4-cyanophenyl)-N,N-dimethylaminoethane and its deactivation pathway

J Chem Phys. 2009 Apr 14;130(14):144307. doi: 10.1063/1.3112402.

Authors

Xing Chen¹, Yi Zhao, Zexing Cao

Affiliation

¹ Department of Chemistry and State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China.

PMID: 19368445
DOI: 10.1063/1.3112402

Abstract

Low-lying singlet states and photophysical deactivation pathways of the electronically decoupled 2-(4-cyanophenyl)-N,N-dimethylaminoethane (PCN2NM) have been investigated by the density functional theory and CASSCF/CASPT2 approaches. PCN2NM in the ground state has two dominant configurations of the alkyl-twisted and alky-stretched structures with an interconversion barrier of 2.5 kcal/mol. The predicted vibrationally resolved weak absorption and fluorescence emission of (1)(S(1)-L(b)) exhibits clearly well-resolved vibronic features, whereas (1)(S(1)-CT) state corresponding to the redshifted fluorescence has no fine structure. Due to the presence of low-energy (1)(S(1)/S(0))(CI), radiationless decay of the excited PCN2NM to the ground state is facile, once the excess energy beyond the barrier is available. Present results show reasonable agreement with experimental observations available and provide a basis for understanding of the dual fluorescence of the electronically decoupled species.