Spectroscopy and Spectral Analysis, Volume. 34, Issue 1, 128(2014)
DFT/TDDFT Study on the Structure and Absorption Spectra of Free Base, N-/Neo-Confused Porphyrin
Porphyrin is an important class of photochemical materials, which has been widely used in various fields. Computational investigations into the ground state structures and orbital energy levels of free base porphyrin (FBP), neo-confused porphyrin (NECP) and N-confused porphyrin (NCP) were performed with density functional theory(DFT). Absorption spectra were calculated at TD-B3LYP/6-31+G(d). Degeneracy of HOMO and HOMO-1 is lost, which would account for the shoulder peaks about the most intense transitions of FBP and NECP. Following FBP, NECP and NCP order, the orbital energy level (OEL) of LUMO decreases while the OEL of HOMO increases, which lead to the red shift of adsorption spectra. The energy difference between LUMO and LUMO+1 is almost the same as the difference between HOMO and HOMO-1, which would account for the only most intense transition of NCP. Solvent effect on ground state structures and absorption spectra was also investigated. The data shows that the character peak of Soret band and Q band changes in different solvent (benzene, chloroform, acetonitrile and water). So we further focus on discussing the N atom position and solvent effects on the energy level and Soret/Q bands of FBP, NCP and NECP, as well as clarifying its variation regularity and mechanism.
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LIU Guo-kui, CAO Hong-yu, LI Shen-min, TANG Qian, YANG Yan-jie, ZHENG Xue-fang. DFT/TDDFT Study on the Structure and Absorption Spectra of Free Base, N-/Neo-Confused Porphyrin[J]. Spectroscopy and Spectral Analysis, 2014, 34(1): 128
Received: Mar. 14, 2013
Accepted: --
Published Online: Jan. 27, 2015
The Author Email: Guo-kui LIU (120565231@qq.com)