Photobehaviour ofZ-1,2-di-(3′-methoxynaphth-2′-yl)ethene as model compound of biphotochromic supermolecules withZ-ethenic bridge

摘要

This work is part of a research project aimed at investigating the behaviour of biphotochromicsupermolecules where two photochromic units of the spirooxazine or chromene series are linked througha conjugated or unconjugated spacer. Preliminary investigations showed that the compounds with ethane,acetylene or ester bridges behave as classical photochromes while those with an ethene bridge showed goodcoloration accompanied by unusual thermal irreversibility at room temperature. The temperature effecton the spectral behaviour allowed such irreversibility to be explained by the occurrence of a cyclizationprocess at the central ethene bond, typical ofZ-diarylethenes. To better understand this photobehaviour, adeep investigation of a model molecule,Z-1,2-di-(3′-methoxynaphth-2′-yl)ethene, was carried out. This paperreports the results obtained on the model molecule and two biphotochromic systems containing benzochromeneand spirooxazine units.