Two-photon fluorescence excitation spectrum of a naphthalene norbornylog: Implications for electron transfer

✍ Scribed by J.R. Reimers; N.S. Hush; D.M. Sammeth; P.R. Callis

• Publisher: Elsevier Science
• Year: 1990
• Tongue: English
• Weight: 406 KB
• Volume: 169
• Category: Article
• ISSN: 0009-2614
• DOI: 10.1016/0009-2614(90)85660-5

✦ Synopsis

Polarized two-photon fluorescence excitation spectra of 1,4-dimethoxy-2,3-dimethyl naphthalene and of a 1,4dimethosy-2,3norbomolog naphthalene, in 0.002 M cyclohexane solution, are reported in the range 665-545 nm at 293 K. Intensity predictions for the 'Lb and 'L, states based upon alternate hydrocarbon pseudoparity rules are confirmed: the weak 'Lb origin is seen as is a strong 'Lb vibronic origin attributed to the naphthalene 4b2, vibration, but the 'L, origin is not identified. However, consideration of the one-photon absorption spectrum then reveals that the 'La origin is higher in energy than is the 'L, origin, confirming that the fast through-bridge photoinduced electron transfer seen in naphthalene-dicyanoethylene norbomologs is an electronically forbidden but vibronically allowed process. As far as we are aware, these are the first examples of such processes.