1,2-Bis[5-(2,2-dicyanovinyl)-2-ethyl-3-thienyl]-3,3,4,4,5,5-hexafluorocyclopent-1-ene, a new photochromic diarylethene compound

Abstract

The title compound, C25H14N4F6S2, is a new symmetric photo­chromic diaryl­ethene which can potentially be applied in optoelectronic devices, such as optical memories, photo switches, and color displays. In the crystalline phase, this mol­ecule, which has crystallographic twofold rotation symmetry, adopts an anti­parallel conformation that can undergo effective photocyclization reactions by a conrotatory mechanism. The distance between the two reactive C atoms is 3.642 (7) Å. The dihedral angle between the central cyclo­pentene ring and each thio­phene ring is 48.0 (2)°. The colourless crystals turn green when exposed to UV radiation and the process is reversible when exposed to visible light of appropriate wavelength.

1,2-Bis[5-(2,2′-dicyanovinyl)-2-n-pentyl-3-thienyl]-3,3,4,4,5,5-hexafluorocyclopent-1-ene: a new photochromic diarylethene compound

“…From the viewpoint of applications to optical memory media and full color diaplays, it is desired to develop photochromic compounds that have sensitivity in the wavelength region of 650-830 nm (Irie, 2000;Gilat et al, 1993Gilat et al, , 1995. We have previously reported three dithienylethenes with dicyano subsitituent: 1,2-bis[2-methyl-5-(2,2′-dicyanovinyl)-3thienyl]-3,3,4,4,5,5-hexafluorocyclopent-1-ene, 2-ethyl analog and 2-butyl analog (Pu et al, 2003(Pu et al, , 2005Zheng et al, 2007), which have relatively long wavelength absorption spectrum (> 700 nm). In order to investigate systematically the substituent effect at the 2-position of the thiophene rings of diarylethenes on their photochemical properties, we have now synthesized the title photochromic diarylethene, (Ia) (Scheme 1), and its structure is presented here.…”

1,2-Bis[2-n-butyl-5-(2,2-dicyanovinyl)-3-thienyl]-3,3,4,4,5,5-hexafluorocyclopent-1-ene: a new photochromic diarylethene compound

“…The title compound, (Ia), was synthesized in 29% total yield by the literature method (Pu, Yang et al, 2005) using 5-nbutyl-thiophene-2-carbaldehyde as the start material. Crystal suitable for X-ray analysis were grown from a solution (diethyl ether/hexane 1/3) by slow evaporation at room temperature (m.p.…”

“…In the present work, the title photochromic diarylethene, (Ia), was synthesized, and its structure is presented here. Previously, we have reported the structure of the 2-methyl, (II), and 2-ethyl analog, (III), of this compound (Pu et al, 2003;Pu, Yang et al, 2005). In order to investigate the substituent effect at the 2-position of the thiophene on the photochemical properties, we have now determined the structure of (Ia).…”