在被乙炔基芘脱氧尿苷电子源和氟脱氧尿苷电子阱取代的DNA双链体中的电荷转移激发态动力学。

Charge transfer excited-state dynamics in DNA duplexes substituted with an ethynylpyrenyldeoxyuridine electron source and a fluorodeoxyuridine electron trap.

作者信息

Gaballah Samir T, Collier Galen, Netzel Thomas L

机构信息

Department of Chemistry, Georgia State University, P.O. Box 4098, Atlanta, Georgia 30332-4098, USA.

出版信息

J Phys Chem B. 2005 Jun 23;109(24):12175-81. doi: 10.1021/jp044457x.

DOI:10.1021/jp044457x

PMID:16852502

Abstract

Studies of six 5-(pyren-1-yl-ethynyl)-2'-deoxyuridine (U(PY))-substituted DNA duplexes in this work test and support the conclusions reported by Gaballah et al. (J. Phys. Chem. B 2005, 109, 5927-5934) based on investigations of 5-(2-pyren-1-yl-ethylenyl)-2'-deoxyuridine (U(PE))-substituted DNA hairpins. As expected because of the rigid ethynyl linker in U(PY) (compared to the flexible ethylenyl linker in U(PE)), U(PY)-substituted duplexes do not show enhanced charge transfer (CT) emission quantum yields for duplexes with 5-fluorodeoxyuridine (U(F)) electron traps near U(PY) compared to duplexes without traps. Furthermore, the average CT lifetime and emission quantum yield of U(PY)-substituted duplexes is independent of the U(F) trap location. These new results strongly suggest that the excess electron in the PY*+/dU*- CT state of U(PY) is restrained from hopping to nearby U(F) traps due to attraction to PY*+.

摘要

在本研究中，对六个5-(芘-1-基-乙炔基)-2'-脱氧尿苷（U(PY)）取代的DNA双链体进行了研究，验证并支持了Gaballah等人（《物理化学杂志B》，2005年，第109卷，5927 - 5934页）基于对5-(2-芘-1-基-乙烯基)-2'-脱氧尿苷（U(PE)）取代的DNA发夹结构的研究得出的结论。正如预期的那样，由于U(PY)中存在刚性乙炔基连接子（与U(PE)中的柔性乙烯基连接子相比），与没有电子陷阱的双链体相比，在U(PY)附近含有5-氟脱氧尿苷（U(F)）电子陷阱的U(PY)取代双链体并未显示出增强的电荷转移（CT）发射量子产率。此外，U(PY)取代双链体的平均CT寿命和发射量子产率与U(F)陷阱位置无关。这些新结果有力地表明，U(PY)的PY*+/dU*- CT态中的多余电子由于对PY*+的吸引而被限制不能跳跃到附近的U(F)陷阱。