Lewis Acid Modulation in a Amido‐functional Diarylethene and Its Hypsochromism Effect

Abstract

A photochromic diarylethene, 1,2-bis(2-methyl-5-(4-N,N-dimethylaminophenyl)thien-3-yl)perfluorocyclopentene in proton-donating media was studied. The ammonium salt came into being in the presence of acetic acid following localization of lone pair electrons of the amino group. The maximum absorption of the salt had a 36 nm hypsochromic shift, and its molar extinction coefficient increased to 3.494×10 4 L•mol -1 •cm -1 . The conjugational and delocalizational energy levels were calculated by Gaussian 98, and its hypsochromic shift mechanism was also discussed.

Ab initio modeling of optical spectra in pH‐sensitive diarylethenes

“…To the best of our knowledge, the present work constitutes the first TD-DFT investigation of DA undergoing joint acidochromic and photochromic effects, at the exception for the 3-21G* calculations performed for IV [23]. Nevertheless, it is worth to pinpoint that previous theoretical simulations, performed for other classes of pH-sensitive photochromes (typically mero-cyanine derivatives), can be found in the literature [26,27].…”

“…threshold (tight threshold in Gaussian). The bulk solvent (acetonitrile for I [22] and II [23], methanol for III [24], dichloromethane and acetonitrile for neutral and charged IV/V, respectively [25]) effects have been included by means of the Polarizable Continuum Model (PCM) [31]. 2.…”

“…Such structure therefore constitutes a valuable multi-addressable switching example. The second DA treated in the present work, II, has been synthesized by Zhang's group [23] and the characteristic visible band of the closed form undergoes an hypsochromic displacement when the two terminal amine are protonated. The electronic spectra of the III is almost insensitive to the pH, as the position of the main band remains constant when the imidazoles are deprotonated in basic environments [24].…”

Acid/alkali gated photochromism of two diarylperfluorocyclopentenes

“…Those molecules were sensitive to both light irradiation and alkali according to their structural characters. Our group [16] reported an amino functional diarylethene whose ring-closed form showed base-acid modulated hypsochromism effect. Those researches revealed that the incorporation of diarylethenes and base-acid sensitive groups might lead to multi-state molecular switches.…”

Esterifiable/hydrolytic control of photochromism of diarylethenes with 8-hydroxyquinoline derivatives

“…Addition of external stimulations, such as chemical reaction [6][7][8][9], heat [10], photon [11,12], electric field [13][14][15][16] etc., to some diarylethenes with special derivative structures will be able to achieve stability of one configuration. Addition of acid/alkali is one of most usually used chemical methods to control reversibility of isomerization of diarylethene [17][18][19][20]. Lehn et al [21] reported several diarylethenes with phenol and pyridine derivatives exhibits proton-gated photochromic properties by deprotonation and reprotonation of the molecules.…”