[2+2] Photocycloaddition Reaction Dynamics of Triplet Pyrimidines

	[2+2] Photocycloaddition Reaction Dynamics of Triplet Pyrimidines
	Yang, Chunfan; Yu, Youqing; Liu, Kunhui; Song, Di; Wu, Lidan; Su, Hongmei
刊名	journal of physical chemistry a
	2011-06-02
卷号	115 期号:21 页码:5335-5345
英文摘要	taking the 266 nm excited pyrimidine (uracil or thymine) with cyclopentene as model reaction systems, we have examined the photoproduct formation dynamics from the [2 + 2] photocycloaddition reactions of triplet pyrimidines in solution and provided mechanistic insights into this important dna photodamage reaction. by combining two compliment methods of nanosecond time-resolved transient ir and uv-vis laser flash-photolysis spectroscopy, the photoproduct formation dynamics as well as the triplet quenching kinetics are measured. characteristic ir absorption bands due to photoproduct formation have been observed and product quantum yields are determined to be similar to 0.91% for uracil and similar to 0.41% for thymine. compared to the measured large quenching rate constants of triplet uracil (1.5 x 10(9) m(-1)s(-1)) or thymine (0.6 x 10(9) m(-1)s(-1)) by cyclopentene, the inefficiency in formation of photoproducts indicates competitive physical quenching processes may exist on the route leading to photoproducts, resulting in very small product yields eventually. such an energy wasting process is found to be resulted from t(1)/s(0) surface crossings by the hybrid density functional calculations, which compliments the experiments and reveals the reaction mechanism.
WOS标题词	science & technology ; physical sciences
类目[WOS]	chemistry, physical ; physics, atomic, molecular & chemical
研究领域[WOS]	chemistry ; physics
关键词[WOS]	fluorescence up-conversion ; excited-state dynamics ; ultrafast internal-conversion ; electronic ground-state ; single-stranded-dna ; thymine dimerization ; aqueous-solution ; conical intersections ; nucleic-acids ; uracil
收录类别	SCI
语种	英语
WOS记录号	WOS:000290914500012
公开日期	2015-11-17
内容类型	期刊论文
源URL	[http://159.226.238.44/handle/321008/142282]
专题	大连化学物理研究所_中国科学院大连化学物理研究所
作者单位	Chinese Acad Sci, Inst Chem, State Key Lab Mol React Dynam, Beijing Natl Lab Mol Sci BNLMS, Beijing 100190, Peoples R China
推荐引用方式 GB/T 7714	Yang, Chunfan,Yu, Youqing,Liu, Kunhui,et al. [2+2] Photocycloaddition Reaction Dynamics of Triplet Pyrimidines[J]. journal of physical chemistry a,2011,115(21):5335-5345.
APA	Yang, Chunfan,Yu, Youqing,Liu, Kunhui,Song, Di,Wu, Lidan,&Su, Hongmei.(2011).[2+2] Photocycloaddition Reaction Dynamics of Triplet Pyrimidines.journal of physical chemistry a,115(21),5335-5345.
MLA	Yang, Chunfan,et al."[2+2] Photocycloaddition Reaction Dynamics of Triplet Pyrimidines".journal of physical chemistry a 115.21(2011):5335-5345.