Direct evidence for mode-specific vibrational energy relaxation from quantum time-dependent perturbation theory. III. The nu(4) and nu(7) modes of nonplanar nickel porphyrin models.
Direct evidence for mode-specific vibrational energy relaxation from quantum time-dependent perturbation theory. III. The nu(4) and nu(7) modes of nonplanar nickel porphyrin models.
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来自量子时间相关微扰理论的模式特定振动能量弛豫的直接证据。
DOI：
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发表时间：
2009
影响因子：
4.4
通讯作者：
J. Straub
中科院分区：
文献类型：
--
作者：
Yong Zhang;J. Straub
用非马尔科夫含时微扰理论，在B3LYP/6-31G(D)水平上研究了镍卟啉(NiP)、镍原卟啉IX(Ni-heme)和镍八乙基卟啉(NiOEP)三种镍卟啉模型的nu(4)和nu(7)振动能谱(VER)的时间尺度和途径。当用D(4h)对称性计算NiP时，它具有与亚铁卟啉(FEP)相同的平面结构和VER性质。镍-血红素和NiOEP的卟啉中心都从平面几何构型中扭曲，呈现非平面结构，类似于细胞色素c中的血红素结构。镍-血红素的时间尺度与平面铁血红素的预测相似，但导出的路径具有明显不同的特征。特别是，平面卟啉的Nu(7)模和约350 cm(-1)的伽马(7)模的泛音之间的强耦合在两个非平面的镍卟啉中都不存在。在NiOEP中没有观察到nu(4)和nu(7)模式之间的直接能量交换，但发现在镍-血红素中nu(4)模式的变化中起着重要作用。异丙酸镍-亚铁血红素参与了镍-亚铁血红素的nu(4)和nu(7)模式的优势途径。然而，与平面铁血红素中的VER途径相比，异丙酸基并没有相对于其他侧链在空间方向上对振动能流起到重要的作用。
The time scales and pathways of vibrational energy relaxation (VER) of the nu(4) and nu(7) modes of three nickel porphyrin models, nickel porphine (NiP), nickel protoporphyrin IX (Ni-heme), and nickel octaethylporphyrin (NiOEP), were studied using a non-Markovian time-dependent perturbation theory at the B3LYP/6-31G(d) level. When NiP is calculated with D(4h) symmetry, it has the planar structure and the same VER properties as ferrous iron porphine (FeP). The porphine cores of both Ni-heme and NiOEP were distorted from a planar geometry, assuming a nonplanar structure, similar to that of the heme structure in cytochrome c. The VER time scales of Ni-heme are found to be similar to those predicted for a planar iron heme, but the derived pathways have distinctly different features. In particular, the strong coupling between the nu(7) mode and the overtone of the approximately 350 cm(-1) gamma(7) mode, observed for planar porphyrins, is absent in both nonplanar nickel porphyrins. Direct energy exchange between the nu(4) and nu(7) modes is not observed in NiOEP, but is found to play an essential role in the VER of the nu(4) mode in Ni-heme. The Ni-heme isopropionate groups are involved in the dominant VER pathways of both the nu(4) and nu(7) modes of Ni-heme. However, in contrast with VER pathways derived in planar iron heme, the isopropionate groups are not observed to play an essential role relative to other side chains in spatially directing the vibrational energy flow.
影响因子：
3.4
作者：
Gruia, Flaviu;Ye, Xiong;Champion, Paul M.
通讯作者：
Champion, Paul M.