2,5-二碘噻吩A带短时光解离动力学的共振拉曼研究

Resonance Raman study of the A-band short-time photodissociation dynamics of 2,5-di-iodothiophene.

作者信息

Ruan Cai-Bin, Wang Hui-Gang, Zhu Hai-Lin, Zheng Xuming, Phillips David Lee

机构信息

Department of Chemistry, Zhejiang Sci-Tech University, Hangzhou, People's Republic of China.

出版信息

J Chem Phys. 2008 Dec 7;129(21):214506. doi: 10.1063/1.3026585.

DOI:10.1063/1.3026585

PMID:19063568

Abstract

Resonance Raman spectra were obtained for 2,5-di-iodothiophene in cyclohexane solution with excitation wavelengths in resonance with its A-band absorption. These spectra indicate that the Franck-Condon region photodissociation dynamics have multidimensional character with motion mostly along the nominal symmetric C(2)C(3)C(4)C(5) stretch nu(2) (1388 cm(-1)) of the thienyl ring and this is accompanied by motions along the nominal symmetric CSC stretch nu(6) (640 cm(-1)), the nominal symmetric C[Single Bond]I stretch nu(7) (187 cm(-1)), the nominal antisymmetric CSC stretch nu(19) (728 cm(-1)), the nominal antisymmetric C(2)C(3)C(4)C(5) stretch nu(16) (1497 cm(-1)), the nominal C(3)C(4) stretch nu(3) (1286 cm(-1)) and four other vibrational modes. A preliminary resonance Raman intensity analysis was done and the results for 2,5-di-iodothiophene were compared to previous results for 2-iodothiophene and di-iodomethane to discuss the mechanism of the symmetric breaking in the initial A-band photodissociation dynamics of 2,5-di-iodothiophene and 2-iodothiophene.

摘要

在环己烷溶液中，以与2,5 - 二碘噻吩的A带吸收共振的激发波长获得了共振拉曼光谱。这些光谱表明，弗兰克 - 康登区域光解离动力学具有多维特征，运动主要沿着噻吩环的标称对称C(2)C(3)C(4)C(5)伸缩振动ν(2)（1388 cm⁻¹），并且伴随着沿着标称对称CSC伸缩振动ν(6)（640 cm⁻¹）、标称对称C - I伸缩振动ν(7)（187 cm⁻¹）、标称反对称CSC伸缩振动ν(19)（728 cm⁻¹）、标称反对称C(2)C(3)C(4)C(5)伸缩振动ν(16)（1497 cm⁻¹）、标称C(3)C(4)伸缩振动ν(3)（1286 cm⁻¹）以及其他四种振动模式的运动。进行了初步的共振拉曼强度分析，并将2,5 - 二碘噻吩的结果与2 - 碘噻吩和二碘甲烷的先前结果进行比较，以讨论2,5 - 二碘噻吩和2 - 碘噻吩初始A带光解离动力学中对称破缺的机制。