1,2-Bis[5-(2,2'-dicyano-vinyl)-2-n-pentyl-3-thien-yl]-3,3,4,4,5,5-hexa-fluoro-cyclo-pent-1-ene: a new photochromic diaryl-ethene compound.

The title compound, C(31)H(26)F(6)N(4)S(2), is a new photochromic dithienylethene with dicyano-vinyl subsitituents. In the crystal structure, the mol-ecule adopts a photoactive anti-parallel conformation, with two n-pentyl groups located on opposite sides of the cyclo-pentene ring. The cyclo-pentene ring assumes an envelope conformation. The distance between the two reactive C atoms on the thio-phene rings is 3.834 (7) Å. One of the n-pentyl groups is disordered over two positions; the site occupancy factors are ca 0.7 and 0.3.