Parameterization of diffusion-influenced intermolecular electron transfer in the static quenching limit

✍ Scribed by B. Stevens; C.J. Biver III

• Publisher: Elsevier Science
• Year: 1994
• Tongue: English
• Weight: 517 KB
• Volume: 226
• Category: Article
• ISSN: 0009-2614
• DOI: 10.1016/0009-2614(94)00748-9

✦ Synopsis

AbStlWt

For the quenching of 9,l Odicyanoanthracene fluorescence by a series of aromatic amines in acetonitrile, a finite-sink analysis provides values of the effective electron-transfer distance R which increase with exergonicity ( -AGO) from 420 pm for benzylamine (AGO= -0.77 eV), close to that expected for a contact pair, to 1000 pm for N,N,N',N'-tetramethyl-pphenylenediamine (AGO= -1.81 eV) which exceeds that associated with a solvent-separated pair. Similar values of R are recovered for the same systems in n-hexane and t-butylbenzene. Estimates of effective electron transfer rate constants Y,> IO" s-t at R are independent of temperature and solvent polarity and show no systematic variance with R, qualitatively consistent with long-range electron transfer from quencher to fluor with increasing probability as their separation is reduced by diffusive approach in the 'inverted region.