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Grills DC, Layne BH, Wishart JF. Coupling Pulse Radiolysis with Nanosecond Time-Resolved Step-Scan Fourier Transform Infrared Spectroscopy: Broadband Mid-Infrared Detection of Radiolytically Generated Transients. APPLIED SPECTROSCOPY 2022; 76:1142-1153. [PMID: 35414202 DOI: 10.1177/00037028221097429] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
We describe the first implementation of broadband, nanosecond time-resolved step-scan Fourier transform infrared (S2-FT-IR) spectroscopy at a pulse radiolysis facility. This new technique allows the rapid acquisition of nano- to microsecond time-resolved infrared (TRIR) spectra of transient species generated by pulse radiolysis of liquid samples at a pulsed electron accelerator. Wide regions of the mid-infrared can be probed in a single experiment, which often takes < 20-30 min to complete. It is therefore a powerful method for rapidly locating the IR absorptions of short-lived, radiation-induced species in solution, and for directly monitoring their subsequent reactions. Time-resolved step-scan FT-IR detection for pulse radiolysis thus complements our existing narrowband quantum cascade laser-based pulse radiolysis-TRIR detection system, which is more suitable for acquiring single-shot kinetics and narrowband TRIR spectra on small-volume samples and in strongly absorbing solvents, such as water. We have demonstrated the application of time-resolved step-scan FT-IR spectroscopy to pulse radiolysis by probing the metal carbonyl and organic carbonyl vibrations of the one-electron-reduced forms of two Re-based CO2 reduction catalysts in acetonitrile solution. Transient IR absorption bands with amplitudes on the order of 1 × 10-3 are easily detected on the sub-microsecond timescale using electron pulses as short as 250 ns.
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Affiliation(s)
- David C Grills
- Chemistry Division, 8099Brookhaven National Laboratory, Upton, NY, USA
| | - Bobby H Layne
- Chemistry Division, 8099Brookhaven National Laboratory, Upton, NY, USA
| | - James F Wishart
- Chemistry Division, 8099Brookhaven National Laboratory, Upton, NY, USA
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Tavani F, Capocasa G, Martini A, Sessa F, Di Stefano S, Lanzalunga O, D'Angelo P. Direct structural and mechanistic insights into fast bimolecular chemical reactions in solution through a coupled XAS/UV–Vis multivariate statistical analysis. Dalton Trans 2021; 50:131-142. [DOI: 10.1039/d0dt03083j] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A combined multivariate and theoretical analysis of coupled XAS/UV–Vis data was proven to be an innovative method to obtain direct structural and mechanistic evidence for bimolecular reactions in solution involving organic substrates.
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Affiliation(s)
- Francesco Tavani
- Dipartimento di Chimica
- Università di Roma “La Sapienza”
- 00185 Roma
- Italy
| | - Giorgio Capocasa
- Dipartimento di Chimica
- Università di Roma “La Sapienza”
- 00185 Roma
- Italy
| | - Andrea Martini
- Dipartimento di Chimica
- Università degli Studi di Torino
- 10125 Torino
- Italy
- The Smart Materials Research Institute
| | - Francesco Sessa
- Dipartimento di Chimica
- Università di Roma “La Sapienza”
- 00185 Roma
- Italy
| | | | | | - Paola D'Angelo
- Dipartimento di Chimica
- Università di Roma “La Sapienza”
- 00185 Roma
- Italy
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Zhuang B, Fujitsuka M, Tojo S, Cho DW, Choi J, Majima T. Influence of Charge Distribution on Structural Changes of Aromatic Imide Derivatives upon One-Electron Reduction Revealed by Time-Resolved Resonance Raman Spectroscopy during Pulse Radiolysis. J Phys Chem A 2018; 122:8738-8744. [PMID: 30351103 DOI: 10.1021/acs.jpca.8b08310] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Structural changes of aromatic imides upon one-electron reduction are investigated by time-resolved resonance Raman spectroscopy during pulse radiolysis. Significant downshifts are observed for both the aromatic ring stretching and carbonyl stretching modes, which are related to a reduction of the bond order and increase of the charge density on these moieties. For three aromatic imides, i.e., 1,8-naphthalene imide (1,8-NI), 2,3-naphthalene imide (2,3-NI), and naphthalene diimide (NDI), the extent of structural changes is found to follow the order: 2,3-NI > 1,8-NI > NDI, reflecting the influence of charge distribution on molecular structure. To further investigate this phenomenon, a series of homologous NDI derivatives with a substituted phenyl group at the imide position are studied. The Raman peaks between 1550 and 1600 cm-1, which are assigned to aromatic stretching vibrations of the NDI moieties, are found to be sensitive to the charge distribution: stronger electron-withdrawing substituents result in these peaks shifting to slightly higher wavenumbers. As supported by a spin density analysis, despite the fact that the added charge is mostly localized on the NDI moiety, in the presence of an electron-withdrawing group, the subtle charge is likely to delocalize on the phenyl fragment, alleviating the effect of one-electron reduction on the molecular structure.
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Affiliation(s)
- Bo Zhuang
- The Institute of Scientific and Industrial Research (SANKEN) , Osaka University , Mihogaoka 8-1 , Ibaraki , Osaka 567-0047 , Japan
| | - Mamoru Fujitsuka
- The Institute of Scientific and Industrial Research (SANKEN) , Osaka University , Mihogaoka 8-1 , Ibaraki , Osaka 567-0047 , Japan
| | - Sachiko Tojo
- The Institute of Scientific and Industrial Research (SANKEN) , Osaka University , Mihogaoka 8-1 , Ibaraki , Osaka 567-0047 , Japan
| | - Dae Won Cho
- The Institute of Scientific and Industrial Research (SANKEN) , Osaka University , Mihogaoka 8-1 , Ibaraki , Osaka 567-0047 , Japan.,Department of Advanced Materials Chemistry , Korea University , Sejong Campus, Sejong 339-700 , Republic of Korea
| | - Jungkweon Choi
- The Institute of Scientific and Industrial Research (SANKEN) , Osaka University , Mihogaoka 8-1 , Ibaraki , Osaka 567-0047 , Japan.,Center for Nanomaterials and Chemical Reactions , Institute for Basic Science (IBS) , Daejeon 305-701 , Republic of Korea
| | - Tetsuro Majima
- The Institute of Scientific and Industrial Research (SANKEN) , Osaka University , Mihogaoka 8-1 , Ibaraki , Osaka 567-0047 , Japan
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