Interactions between purine derivatives: Electronic spectral studies. II. Excition interactions in the dimer of 6-methylpurine in aqueous solution

✍ Scribed by G. R. Kelly; T. Kurucsev

• Book ID: 102761526
• Publisher: Wiley (John Wiley & Sons)
• Year: 1974
• Tongue: English
• Weight: 552 KB
• Volume: 13
• Category: Article
• ISSN: 0006-3525
• DOI: 10.1002/bip.1974.360130412

✦ Synopsis

Abstract

From a study of the concentration dependence of the ultraviolet absorption spectra of aqueous solutions of 6‐methylpurine, the spectra of monomeric and dimeric species have been derived. The dichroic spectrum of 6‐methylpurine in stretched poly(vinyl alcohol) films has been determined. The absorption envelope of 6‐methylpurine up to 44,000 cm^−1^ appears to include a low‐intensity nitrogen (π*,n) transition at the low wavenumber tail and two additional electronic transitions of dominant intensities. Both the experimental dichroic ratios and theoretical calculations suggest that the letter two transitions are in‐plane (π*,π) types. Analysis of the dimer species spectrum in terms of exciton interactions between molecules in “sandwich” conformation has been carried out. The interaction between the moments of the lowest energy (π*,π) transitions of the molecule in the dimer seems to result in transfer rates of energy of the order of 10^13^ sec^−1^ between the two molecules.