Tuning the optical properties of dithienylethenes: Theoretical insights

A class of dithienylethenes and its possible derivatives is explored with Density Functional Theory (DFT) and Time-Dependent DFT methods. After a comparison of different functional performances, 15 dithienylethenes have been submitted to calculation at the B1B95/6-311G(d,p) level in order to get further insights on the substitution impact on the energetic and optical properties of both isomers. Aromatic, donor, acceptor and donor/acceptor series are investigated. Simultaneously, in a context of molecular design of new compounds with interesting spectroscopic properties, theoretical absorption features are linearly correlated to the experimental Hammet parameter σR, which allows a fast and efficient prediction of the first absorption wavelength.

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► TD-DFT is used to investigate the spectral properties of dithienylethenes.
► The features of both open and closed-ring isomers are investigated.
► Open and closed isomers behave differently upon substitution effect.
► σR Hammet parameters reproduce the evolution of the first transition wavelength.
► Substituents with large σR enhance the contrast between on and off states.