Xu Lian-Cai, Li Zun-Yun, Tan Wei, He Tian-Jing, Liu Fan-Chen, Chen Dong-Ming
Department of Chemical Physics, University of Science and Technology of China, Hefei, Anhui 230026, PR China.
Spectrochim Acta A Mol Biomol Spectrosc. 2005 Dec;62(4-5):850-62. doi: 10.1016/j.saa.2005.03.015. Epub 2005 Apr 15.
The vibrational spectra of meso-tetraphenylporphyrin diacid (H4TPP2+) have been studied with the density functional theory. Raman and IR spectra of H4TPP2+ and its N-deuterated analogue (D4TPP2+) are measured and compared with the computational results. Complete assignments of observed IR and Raman bands were proposed on the bases of calculation results. The DFT calculations reproduce 140 observed fundamentals with the RMS 8.6 cm-1. The computational as well as the experimental results reveal that the saddle-distortion of porphyrin macrocycle for the diacid leads to a significant effect on its vibrational spectra. Especially, several out-of-plane skeletal modes, which were either unobserved or very weak in the Raman spectra of CuTPP and H2TPP, are activated in the Raman spectra of the diacids. In addition, enhancement for the Raman bands of phenyl CC stretching modes were observed and attributed to the conjugation effect of pi-systems of the phenyl and the porphyrinato macrocycles.
利用密度泛函理论研究了中位四苯基卟啉二酸（H4TPP2+）的振动光谱。测量了H4TPP2+及其N-氘代类似物（D4TPP2+）的拉曼光谱和红外光谱，并与计算结果进行了比较。基于计算结果对观察到的红外和拉曼谱带进行了完整的归属。密度泛函理论计算以8.6 cm-1的均方根误差重现了140个观察到的基频。计算结果和实验结果均表明，二酸的卟啉大环的鞍形畸变对其振动光谱有显著影响。特别是，在CuTPP和H2TPP的拉曼光谱中未观察到或非常弱的几个面外骨架模式，在二酸的拉曼光谱中被激活。此外，观察到苯基C-C伸缩模式的拉曼谱带增强，这归因于苯基和卟啉大环的π-体系的共轭效应。
