Solvent Polarity Dependence of Photochromic Reactions of a Diarylethene Derivative As Revealed by Steady-State and Transient Spectroscopies

Abstract

Solvent polarity dependence of photochromic reactions such as cyclization and cycloreversion of a photochromic diarylethene derivative, 1,2-bis­(2-methyl-3-benzothienyl)­perfluorocyclopentene, was investigated by steady-state spectroscopic and femtosecond laser photolysis methods. For the cyclization reaction, it was revealed that the quantum yield decreased with an increase in solvent polarities, mainly due to the decrease in the fraction of the conformer with C 2 symmetry favorable for the cyclization. This result indicated that the branching ratio for the cyclization and the deactivation to the open-ring isomer at the conical intersection was almost independent of the solvent polarity. On the other hand, it was found for the cycloreversion process that the closed-ring isomer in the S1 state rapidly deactivated into the ground state in competition with the activated process leading to the conical intersection providing a pathway toward both open- and closed-ring minima in the ground state. The cycloreversion reaction quantum yield also decreasing with an increase in the solvent polarity was attributed to larger increase of the direct deactivation into the ground state from the excited state minimum of the closed-ring isomer.

Optical properties of gold nanoparticles decorated with furan-based diarylethene photochromic molecules

“…3, inset) we determined the upper value of the rise-time as the characteristic of the gradual growth of optical density during the ring-closing reaction of YnPhT molecules to be equal to 420 fs. This value is smaller than that of thiophene based DAE [45][46] , revealing a faster ring-closing reaction of furanbased DAE functionalized by 4-mercaptophenyl-ethynyl side groups. From these results of the pump probe experiment we expect that furans grafted onto AuNP will also show a faster cyclization dynamics compared with thiophenes.…”

Picosecond cyclization reaction dynamics of furan-based diarylethene with thiosemicarbazone side-chain groups

“…Thus, we found that the upper boundary of the rise time is 1.1 ps for photoinduced cyclization reaction of CF5-TSC. The determined time is slightly larger than the one for some others similar thiophene-based DAEs [10][11][12][13], but is lower compared to equivalent DAEs with various modifications of side-chains groups [14][15][16]. Therefore, we suspect that exactly the side-chain groups of the molecules play the key role in processes of ring-closing reaction [31,32].…”

“…Further measurements with shorter laser pulses are required for a more precise determination of the ring-closing time constant. We do not exclude that in solvents with different polarity CF5-TSC might display different time of cyclization reaction [15,35].…”

Crystal structure of 4-phenyl-3-((4-phenyl-1H-1,2,3-triazol-1-yl)methyl)-1H-1,2,4-triazole-5(4H)-thione, C17H14N6S

“…The design and synthesis of novel triazole-thione bearing different aromatic moieties have become a broad area in bio-organic synthesis research [11,12]. 1,2,4-Triazoles are used as poly-chelate ligands for the synthesis of metal complexes [13].…”