Multinuclear NMR structural characterization of an unprecedented photochromic allene intermediate.
[structure: see text] An o-allenyl-p-methoxyphenol intermediate (Int) was for the first time proved to be involved in the photochromic reaction of 2,2-di(4-fluorophenyl)-6-methoxy-2H-1-chromene (FC). Transoid-cis (TC) and transoid-trans (TT) photomerocyanines and the intermediate Int are generated by UV irradiation of FC. Visible light converts TC and TT into Int. The monitoring of the reactions was carried out on the basis of (1)H, (13)C, (19)F, and (2)H NMR spectroscopy.
Laboratoire de Physique et LARMN, UMR CNRS 8009, Faculté de Pharmacie, Université de Lille 2, France.
Stephanie
S
Delbaere
Jean-Claude
JC
Micheau
Gaston
G
Vermeersch