Efficient deactivation of a model base pair via excited-state hydrogen transfer

被引：311

作者：

Schultz, T

Samoylova, E

Radloff, W

Hertel, IV

Sobolewski, AL

Domcke, W

机构：

[1] Max Born Inst, D-10247 Berlin, Germany

[2] Polish Acad Sci, Inst Phys, PL-02668 Warsaw, Poland

[3] Tech Univ Munich, Dept Chem, D-85747 Garching, Germany

来源：

SCIENCE | 2004年 / 306卷 / 5702期

关键词：

D O I：

10.1126/science.1104038

中图分类号：

O [数理科学和化学]; P [天文学、地球科学]; Q [生物科学]; N [自然科学总论];

学科分类号：

07 ; 0710 ; 09 ;

摘要：

We present experimental and theoretical evidence for an excited-state deactivation mechanism specific to hydrogen-bonded aromatic dimers, which may account, in part, for the photostability of the Watson-Crick base pairs in DNA. Femtosecond time-resolved mass spectroscopy of 2-aminopyridine clusters reveals an excited-state lifetime of 65+/-10 picoseconds for the near-planar hydrogen-bonded dimer, which is significantly shorter than the lifetime of either the monomer or the 3- and 4-membered nonplanar clusters. Ab initio calculations of reaction pathways and potential-energy profiles identify the mechanism of the enhanced excited-state decay of the dimer: Conical intersections connect the locally excited (1)pipi* state and the electronic ground state with a (1)pipi* charge-transfer state that is strongly stabilized by the transfer of a proton.

引用

页码：1765 / 1768

页数：4

共 14 条

[1] High-resolution electronic spectra of 2-hydroxy and 2-aminopyridine. Perturbing effects of the nitrogen atom in the aromatic ring [J].