Photocontrollable Modulation of Frontier Molecular Orbital Energy Levels of Cyclopentenone-Based Diarylethenes

Abstract

Photoswitchable diarylethenes provide a unique opportunity to optically modulate frontier molecular orbital energy levels, thereby opening an avenue for the design of electronic devices such as photocontrollable organic field-effect transistors (OFETs). In the present work, the absolute position of the frontier orbital levels of nonsymmetrical diarylethenes based on a cyclopentenone bridge has been studied using cyclic voltammetry and density functional theory (DFT) calculations. It has been shown that varying heteroaromatic substituents make it possible to change the absolute positions of the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) of both diarylethene photoisomers. The data obtained are used to refine the operation mechanism of the previously developed OFET devices, employing the cyclopentenone-derived diarylethenes at the dielectric/semiconductor interface.

Theoretical Investigation of para Amino-Dichloro Chalcone Isomers. Part II: A DFT Structure–Stability Study of the FMO and NLO Properties

“…The Z chalcone isomer stability calculated with the (GO + DC) procedure is (3,5) > anti (2,4) > anti (2,5) > syn (3,4) > (2,6) > anti (2,3), which is similar to that obtained from (GO/ SPDC), as shown in Table 1. The chromen isomer stability order is (5,8a) > (5,8) > (6,8) > (5,7) > (5,6) > (6,7), which agrees completely with that obtained using (GO/SPDC).…”

“…In Part I, we investigated the stability of each conformer, and the results indicated that the syn (2,3), syn (2,4), and syn (2,5) conformers are more stable than their anti-counterparts. However, the anti (3,4) of the E chalcone was more stable than the syn (3,4) E chalcone. Nevertheless, the Z chalcone series with the anticonformers are more stable than the syn conformers for (2,3), (2,4), and (2,5), while the syn (3,4) Z chalcone is more stable than its anti-counterpart.…”

“…The isomer stability order of this investigation is E chalcone > Z chalcone > chromen, which is the same as the ordering obtained from the energy calculations which employed the procedure (GO/SPDC). In Part I of this investigation, the order of the calculated stability of the electronic energies without using dispersion correction of the E dichloro amino chalcone isomers was: (3,5) > syn (2,4) > syn (2,5) > anti (3,4) > (2,6) >syn (2,3). However, on introducing the (GO/SPDC) procedure, the order becomes: (3,5) > syn (2,5) > syn (2,4), anti (3,4) > (2,6) > syn (2,3).…”

Providing theoretical insight into the role of symmetry in the photoisomerization mechanism of a non-symmetric dithienylethene photoswitch

“…Several authors have studied numerous DTE derivatives from both experimental 1–4,11–18 and theoretical 1,2,5,16–25 perspectives for more than three decades. Although many aspects of DTEs have been clarified, the control of the QY of the photocyclization and photoreversion is still a puzzle.…”

“…2 These features make them excellent candidates for developing modern technologies, for example, application of molecular photoswitches 1,2 and photomolecular motors 2,7 in nanomachines 8 and molecular electronic devices. 7,[9][10][11] Several authors have studied numerous DTE derivatives from both experimental [1][2][3][4][11][12][13][14][15][16][17][18] and theoretical 1,2,5,[16][17][18][19][20][21][22][23][24][25] perspectives for more than three decades. Although many aspects of DTEs have been clarified, the control of the QY of the photocyclization and photoreversion is still a puzzle.…”