1001671-82-4Relevant academic research and scientific papers
Photoswitchable π-Extended Dithienylethenes with an Attached Molecular Recognition Site
Bittner, Iris,Lüning, Ulrich
, p. 2592 - 2602 (2018)
Photoswitchable dithienylethenes have been extended in positions 5 and 5′ with π-systems resulting in absorptions of light with longer wavelengths when electrocyclization and -reversion are carried out. The extended π-systems also improve conductivities potentially. cis-Orientation of the thienyl rings was accomplished by integrating the central double bond into maleic imides. The nitrogen atoms of the imides were substituted by a Hamilton receptor allowing supramolecular binding of complementary guests such as barbiturates. Both, a stiff and a flexible connection between photoswitch and receptor was realized. The resulting photoswitches showed reversible switching over several cycles and were able to bind diethyl barbiturate with binding constants of > 104 m–1.
Single-crystalline photochromism of diarylethene dimers bridged by a spiro structure
Kobatake, Seiya,Kuma, Shunpei,Irie, Masahiro
, p. 960 - 967 (2007)
New types of diarylethene dimers bridged by a spiro structure were synthesized. One of their dimers formed three kinds of polymorphic forms by recrystallization from different solvents: hexane (1a-α), acetone (1a-β), and acetonitrile (la-γ). In crystals of 1a-α and 1a-β the molecules are packed in solvent-free crystal structures, whereas crystal 1a-γ includes acetonitrile molecules in the crystal. The difference of significant photochromic reactivities in their polymorphic crystals was observed for photocoloration reactions. Crystals 1a-β and 1a-γ showed photochromism in the single-crystal phase, but 1a-α did not do so. Their photochromic reactivity was found to depend on the distance between the reactive carbon atoms by X-ray crystallographic analysis. When the distance is less than 4.2 A in the antiparallel conformation, the molecule can undergo photochromism in the crystal. On the other hand, crystals of bromo-substituted diarylethene dimer (2a) cannot be suitable for X-ray crystallographic analysis when it was recrystallized from hexane, acetone, and acetonitrile. However, it formed single crystal by recrystallization from p-xylene, which showed photochromism in the crystalline phase. The edge-to-face aromatic interaction between p-xylene molecules assisted the crystal growth of the diarylethene dimer. Upon irradiation with ultraviolet light, two kinds of the enantiomers, (M,SS)- and (P,RR)-2b, are produced. Partial photobleaching reactions of either of the two enantiomers by irradiation with linearly polarized visible light were confirmed by polarized absorption spectroscopy. Copyright
Design, synthesis and study of a photochromic α,ω-diene: Toward new classes of photoswitchable polymers
Joo, Wontae,Bielawski, Christopher W.
, p. 2486 - 2491 (2019/03/06)
A 4,5-dithienylimidazolium salt outfitted with pendant styrenyl groups was synthesized and studied. The salt was found to undergo reversible electrocyclization upon UV irradiation; subsequent exposure to visible light reversed the reaction. Acyclic diene metathesis (ADMET) polymerization of the salt afforded a novel fluorescent polyelectrolyte.
