Certain photochromic fulgide compounds and method for their synthesis

摘要

The invention provides a photochromic material characterized by an improvement in balance of the substituents in the conventional furylfulgides and represented by the general formula: <IMAGE> (wherein R represents an alkyl chain having 5 to 31 carbon atoms). According to this molecular structure, a mutually appropriate steric hindrance is induced between the isopropylidence group and the long-chain alkyl group to make the regio isomer unstable, thus preventing the regio isomer from being by-produced while also inhibiting any isomerization reaction from occuring in the synthesis of the fulgide. Further, a good balance of hydrophilic part and hydrophobic part is produced to facilitate formation of a Langmuir-Blodgett film.