Ac. Benniston et A. Harriman, PHOTOISOMERIZATION OF A STERICALLY CONSTRAINED MEROCYANINE DYE, Journal of the Chemical Society. Faraday transactions (Print), 94(13), 1998, pp. 1841-1847
Citations number
25
Categorie Soggetti
Chemistry Physical","Physics, Atomic, Molecular & Chemical
A particular concern regarding the photophysical properties of merocya
nine 540 derivatives, and related cyanine dyes, involves identifying w
hich double bond in the central polyenic bridge undergoes light-induce
d isomerization. In order to address this issue we have synthesized a
novel merocyanine dye in which the first double bond is built into a c
yclic structure that prevents isomerization at this site. Contrary to
expectations, the dye photoisomerizes with reasonable efficiency, such
that the quantum yields of fluorescence and intersystem crossing to t
he triplet manifold are kept small. For this dye, isomerization must t
ake place at the central double bond. It is further shown that the str
ategy of inserting bulky or constraining groups into the polyenic brid
ge is not a viable approach for the development of highly fluorescent
merocyanine dyes.