On the excited-state geometry of the adenine residue as revealed by a preresonance Raman effect

✍ Scribed by Masamichi Tsuboi; Akiko Y. Hirakawa; Yoshifumi Nishimura; Issei Harada

• Publisher: John Wiley and Sons
• Year: 1974
• Tongue: English
• Weight: 541 KB
• Volume: 2
• Category: Article
• ISSN: 0377-0486
• DOI: 10.1002/jrs.1250020608

✦ Synopsis

Abstract

The Raman specrum of β‐adenosine‐5′‐phosphoric acid has been observed in its aqueous solution with 6471, 5145, 4880, 4579, 4579, and 3511 Å excitation. An examination of the manner of increase of the intensities of the Raman lines at 1580 and 1484 cm^−1^ of the adenine residue indicated that the electronic excited state corresponding to a weak absorption band at 276 nm is responsible for these Raman scatterings. This idea has been supported by a similar examination of the Raman spectrum of β‐adenosine‐3′,5′‐cyclic phosphoric acid and an examination of the effect of temperature on the Raman spectra of poly rA and poly(rA‐rU). A discussion is included of the geometrical structure of the adenine residue in its lowest‐singlet electronic excited state, based on the vibrational structure of the fluorescence spectrum, the result of a normal coordinate treatment, and the result of a semiempirical Pariser‐Parr‐Pople calculation, as well as the Raman data.