Synthesis and unexpected photochemical behaviour of biphtohromic systems involving spirooxazines and naphthopyrans linked by an ethylenic bridge

摘要

Using the Witting reaction, six new biphotochromic compounds have been prepared by the coupling of coveniently functionalised spiro[indoline-naphthoxazines] and naphthopyrans. Compared to molecules taken individually, unusual photochromic behaviour has been detected with compounds for which a double bond of Z-configuration links both entities by the 5 or 5' positions of the naphthalenic parts. Indeed, in this case the thermally stable uncoloured and coloured forms (bistable system) can be photochemically converted acting as photochemical switches.