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Xue J, Li Y, Du L, Du Y, Tang W, Zheng X, Phillips DL. Direct Observation of 4-Phenoxyphenylnitrenium Ion: A Transient Absorption and Transient Resonance Raman Study. J Phys Chem B 2015; 119:14720-7. [PMID: 26503835 DOI: 10.1021/acs.jpcb.5b07218] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Femtosecond (fs) and nanosecond (ns) transient absorption (TA) and single pulse transient resonance Raman spectroscopic investigation of the intermediates after laser photolysis of 4-phenoxyphenyl azide in acetonitrile and mixed aqueous solution is reported. fs-TA results show that the singlet 4-phenoxyphenylnitrene was produced immediately after photolysis of the azide. Then, the singlet nitrene underwent intersystem crossing (ISC) and ring expansion to generate triplet nitrene and ketenimine in acetonitrile with t = 346 ps or protonation in mixed aqueous solution with t = 37 ps, respectively, a little slower than the counterparts of the methoxy one (108 and 5.4 ps for ISC and protonation processes, respectively). The transient Raman spectrum combined density functional theory (DFT) calculation predicting the structure and vibrational frequencies suggested that phenoxyphenylnitrenium ion has a comparable quinoidal character to that of methoxy- and ethoxy-phenylnitrenium ions. All of these results indicated that the phenoxy substitution has some impact on the reactivity of phenylnitrene but a slight influence on the structure of phenylnitrenium ion.
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Affiliation(s)
- Jiadan Xue
- Engineering Research Center for Eco-Dyeing & Finishing of Textiles, Ministry of Education, Zhejiang Sci-Tech University , Hangzhou, 310018, China.,Department of Chemistry, Zhejiang Sci-Tech University , Hangzhou, 310018, China
| | - Yafang Li
- Department of Chemistry, Zhejiang Sci-Tech University , Hangzhou, 310018, China
| | - Lili Du
- Department of Chemistry, The University of Hong Kong , Hong Kong, S. A. R., China
| | - Yong Du
- Centre for THz Research, China Jiliang University , Hangzhou, 310018, China
| | - Wenjian Tang
- School of Pharmacy, Anhui Medical University , Hefei, 230032, China
| | - Xuming Zheng
- Department of Chemistry, Zhejiang Sci-Tech University , Hangzhou, 310018, China
| | - David Lee Phillips
- Department of Chemistry, The University of Hong Kong , Hong Kong, S. A. R., China
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Xue J, Vyas S, Du Y, Luk HL, Chuang YP, But TYS, Toy PH, Wang J, Winter AH, Phillips DL, Hadad CM, Platz MS. Time-Resolved Resonance Raman and Computational Investigation of the Influence of 4-Acetamido and 4-N-Methylacetamido Substituents on the Chemistry of Phenylnitrene. J Phys Chem A 2011; 115:7521-30. [PMID: 21648388 DOI: 10.1021/jp201821d] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Affiliation(s)
- Jiadan Xue
- Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong S.A.R., People's Republic of China
| | - Shubham Vyas
- Department of Chemistry, The Ohio State University, 100 West 18th Avenue, Columbus, Ohio 43210, United States
| | - Yong Du
- Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong S.A.R., People's Republic of China
| | - Hoi Ling Luk
- Department of Chemistry, The Ohio State University, 100 West 18th Avenue, Columbus, Ohio 43210, United States
| | - Yung Ping Chuang
- Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong S.A.R., People's Republic of China
| | - Tracy Yuen Sze But
- Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong S.A.R., People's Republic of China
| | - Patrick H. Toy
- Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong S.A.R., People's Republic of China
| | - Jin Wang
- Department of Chemistry, The Ohio State University, 100 West 18th Avenue, Columbus, Ohio 43210, United States
| | - Arthur H. Winter
- Department of Chemistry, The Ohio State University, 100 West 18th Avenue, Columbus, Ohio 43210, United States
| | - David Lee Phillips
- Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong S.A.R., People's Republic of China
| | - Christopher M. Hadad
- Department of Chemistry, The Ohio State University, 100 West 18th Avenue, Columbus, Ohio 43210, United States
| | - Matthew S. Platz
- Department of Chemistry, The Ohio State University, 100 West 18th Avenue, Columbus, Ohio 43210, United States
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Voskresenska V, Wilson RM, Panov M, Tarnovsky AN, Krause JA, Vyas S, Winter AH, Hadad CM. Photoaffinity labeling via nitrenium ion chemistry: protonation of the nitrene derived from 4-amino-3-nitrophenyl azide to afford reactive nitrenium ion pairs. J Am Chem Soc 2009; 131:11535-47. [PMID: 19624129 DOI: 10.1021/ja902224m] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Phenyl azides with powerful electron-donating substituents are known to deviate from the usual photochemical behavior of other phenyl azides. They do not undergo ring expansion but form basic nitrenes that protonate to form nitrenium ions. The photochemistry of the widely used photoaffinity labeling system 4-amino-3-nitrophenyl azide, 5, has been studied by transient absorption spectroscopy from femtosecond to microsecond time domains and from a theoretical perspective. The nitrene generation from azide 5 occurs on the S(2) surface, in violation of Kasha's rule. The resulting nitrene is a powerful base and abstracts protons extremely rapidly from a variety of sources to form a nitrenium ion. In methanol, this protonation occurs in about 5 ps, which is the fastest intermolecular protonation observed to date. Suitable proton sources include alcohols, amine salts, and even acidic C-H bonds such as acetonitrile. The resulting nitrenium ion is stabilized by the electron-donating 4-amino group to afford a diiminoquinone-like species that collapses relatively slowly to form the ultimate cross-linked product. In some cases in which the anion is a good hydride donor, cross-linking is replaced by reduction of the nitrenium ion to the corresponding amine.
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Affiliation(s)
- Valentyna Voskresenska
- Department of Chemistry and the Center for Photochemical Sciences, Bowling Green State University, Bowling Green, Ohio 43403, USA
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Chan PY, Ong SY, Zhu P, Leung KH, Phillips DL. Transient resonance Raman and density functional theory investigation of the 4-acetamidophenylnitrenium ion. J Org Chem 2003; 68:5265-73. [PMID: 12816488 DOI: 10.1021/jo0300439] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
This paper reports a transient resonance Raman and density functional theory study of the 4-acetamidophenylnitrenium ion in a mostly aqueous solvent. The transient Raman bands combined with results from density functional theory calculations indicate that the spectrum should be assigned to the singlet state of the 4-acetamidophenylnitrenium ion. The 4-acetamidophenylnitrenium ion was found to have a substantial iminocyclohexadienyl character comparable to previously studied para-phenyl-substituted phenylnitrenium ions and noticeable charge on both the acetamido and nitrenium moieties. The structure and properties of the 4-acetamidophenylnitrenium ion are compared to those of other arylnitrenium ions. We briefly discuss the chemical reactivity and selectivity of the para-acetamido-substituted phenylnitrenium ions compared to para-phenyl- or para-alkoxy-substituted phenylnitrenium ions.
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Affiliation(s)
- Pik Ying Chan
- Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong S. A. R., P. R. China
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