Reversed photochromism reactivity of malononitrile attached bisthienylthene

An electron acceptor, malononitrile, was attached to bisthienylethene derivative. The significant influence of electron nature result a reversed phtochromism. Investigation of MT in THF demonstrates the reversible ring-open and ring-close. Upon irradiation of 405nm laser, the solution color changed from yellowish to colorless, which is different from most of the photochromic colored phenomenon. Upon 254nm irradiation, the original yellowish state can be recovered. Due to the attachment of malononitrile, the photo-/thermal-stability were enhanced. The ring-open/ring-closed forms were optimized by Dmol(3). The distance between photocyclizing atoms in aptiparallel conformation meets the requirement for photochromic reaction. And the calculated absorption values were also in agreement with the experimental ones.