Controllable and Reversible Inversion of the Electronic Structure in Nickel N-Confused Porphyrin: A Case When MCD Matters

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• 作者：Saovalak Sripothongnak ; Christopher J. Ziegler ; Michael R. Dahlby ; Victor N. Nemykin
• 刊名：Inorganic Chemistry
• 出版年：2011
• 出版时间：August 1, 2011
• 年：2011
• 卷：50
• 期：15
• 页码：6902-6909
• 全文大小：1225K
• 年卷期：v.50,no.15(August 1, 2011)
• ISSN：1520-510X

文摘

Nickel N-confused tetraphenylporphyrin, 1, and nickel 2-N-methyl-N-confused tetraphenylporphyrin, 1-Me, exhibit unusual sign-reversed (positive-to-negative intensities in ascending energy) MCD spectra in the Q-type band region, suggesting a rare 螖HOMO < 螖LUMO relationship between 蟺 and 蟺* MOs in the porphyrin core. Simple and reversible deprotonation of the external NH proton in 1 dramatically changes the electronic structure of the porphyrin core into the 螖HOMO > 螖LUMO combination characteristic for the meso-(tetraaryl)porphyrins. DFT, time-dependent DFT, and semiempirical ZINDO/S calculations on 1, 1-Me, and 1^- confirm the experimental finding and successfully explain the MCD pattern in the target compounds.