1,10-Phenanthroline, complexes with rare metals

There continues to be a high level of interest shown in photochromic systems. The optically active l,T-bi-2-naphthol gives an optically active intramolecular addition product (37) on irradiation, and on prolonged exposure, cycloreversion occurs which gives evidence for a photoequilibrium between the asymmetric molecules (Cavazza et al). A number of reports within the year describe a variety of aspects of the well-known thermally-reversible spiroindoline-oxazine to photo-merocyanine conversion. For example, the process is sensitised by triplet cam-phorquinone (Favaro et al.), the influence of complexation on indoline and phenanthroline spiropyrans with transition and rare earth metal ions has been described (Atabekyan et al.), and the photochromism of other derivatives in water using vesicles and y-cyclodextrin is reported to be faster than in methanol with the process most favoured in the vesicles (Ishiwatari et al.). 

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