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Ozeki M, Orito M, Ishikawa H. Observation of the Infrared-Induced Structural Change in the Microscopic Hydrogen Bond Network of Phenol-Methanol Cluster Cations in a Cold-Ion Trap. J Phys Chem A 2024; 128:5873-5882. [PMID: 38996183 DOI: 10.1021/acs.jpca.4c01998] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/14/2024]
Abstract
To gain insight into microscopic hydrogen bond networks, we measured ultraviolet photodissociation (UVPD) spectra of the phenol-methanol 1:3 cluster cation, [PhOH(MeOH)3]+ trapped in a variable temperature ion trap. At low temperatures, an isomer with a ring-type hydrogen bond structure dominates, whereas at higher temperatures the chain-type isomers become dominant due to the flexibility of their hydrogen bond structures. We also found a clear temperature dependence of the spectral features, such as band position and width. In addition to the above measurement, we observed the infrared (IR) induced isomerization of [PhOH(MeOH)3]+ to study the dynamical aspects of hydrogen bond networks. We succeeded in observing IR-induced isomerization from the ring to chain forms of [PhOH(MeOH)3]+ at low temperature. The isomerization was clearly identified as a change in the UVPD spectra. The time evolution of the UVPD spectra after IR excitation indicated that the IR-induced isomerization occurs within a nanosecond. The chain-type isomers produced by the IR-induced isomerization are then converted back to the ring-type form by collisions with cold He buffer gas in the trap. This backward isomerization proceeds with a time constant of 100 μs under our experimental conditions. In this study, we evaluated the temperatures of the chain isomers during the backward isomerization on the basis of the spectral features.
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Affiliation(s)
- Masayoshi Ozeki
- Department of Chemistry, School of Science, Kitasato University, Sagamihara 252-0373, Japan
| | - Masataka Orito
- Department of Chemistry, School of Science, Kitasato University, Sagamihara 252-0373, Japan
| | - Haruki Ishikawa
- Department of Chemistry, School of Science, Kitasato University, Sagamihara 252-0373, Japan
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Nagasawa H, Ogawa S, Kashihara W, Isozaki T, Hirata K, Ishiuchi SI, Fujii M, Suzuki T. Conformational preference of 2-(4-methoxyphenyl)ethanol studied by supersonic jet spectroscopy: Intramolecular OH/π interaction. J Chem Phys 2024; 160:024303. [PMID: 38189621 DOI: 10.1063/5.0184664] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2023] [Accepted: 12/20/2023] [Indexed: 01/09/2024] Open
Abstract
A π-type hydrogen bonding between the OH group and the π electron is a crucial factor for the conformational preference of the molecular structure with a flexible group. However, the information on the effect of the substituent on the OH/π interaction is insufficient. The laser-induced fluorescence (LIF) excitation, the dispersed fluorescence (DF), the IR-UV hole-burning, and the IR dip spectra of jet-cooled 2-(4-methoxyphenyl)ethanol were measured for the first time. Almost all bands observed in the spectral region of 35 550-36 500 cm-1 in the LIF excitation spectrum were successfully assigned with the DF and the IR-UV hole-burning spectra coupled with the quantum chemical calculation at M06-2x/6-311G and MP2/6-311G levels. Five conformers were found in the LIF excitation spectrum. The most stable conformer was Ggπ, and the second most stable conformer was Ggπ' (the trans rotamer of the methoxy group for Ggπ). Ggπ and Ggπ' had the OH group directed toward the π electron system of the benzene ring. The OH stretching frequency of Ggπ/Ggπ' of MPE in the IR dip spectra was red-shifted against that of Ggπ of phenylethanol, indicating that the introduction of the methoxy group would enhance the intramolecular OH/π interaction. In addition, the torsional vibration between the benzene ring and the side chain (-CH2CH2OH) (mode 63) was observed in the DF spectra of the Ggπ-00 and Ggπ'-00 band excitation, but their intensities were rather different, resulting from the different orientation of the OH group for each conformer toward the π electron system. The methoxy group would increase the negative charge on the benzene ring and would enhance the intramolecular OH/π interaction through the electrostatic interaction.
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Affiliation(s)
- Hironari Nagasawa
- Department of Chemistry and Biological Science, Aoyama Gakuin University, 5-10-1 Fuchinobe, Sagamihara, Kanagawa 252-5258, Japan
| | - Sakuya Ogawa
- Department of Chemistry and Biological Science, Aoyama Gakuin University, 5-10-1 Fuchinobe, Sagamihara, Kanagawa 252-5258, Japan
| | - Wataru Kashihara
- Department of Chemistry and Biological Science, Aoyama Gakuin University, 5-10-1 Fuchinobe, Sagamihara, Kanagawa 252-5258, Japan
| | - Tasuku Isozaki
- Division of Natural Sciences, College of Arts and Sciences, J. F. Oberlin University, 3758 Tokiwa-machi, Machida, Tokyo 194-0294, Japan
| | - Keisuke Hirata
- Laboratory for Chemistry and Life Science, Institute for Innovative Research, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama 226-8503, Japan
- Department of Chemistry, School of Science, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8550, Japan
| | - Shun-Ichi Ishiuchi
- Laboratory for Chemistry and Life Science, Institute for Innovative Research, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama 226-8503, Japan
- Department of Chemistry, School of Science, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8550, Japan
| | - Masaaki Fujii
- Laboratory for Chemistry and Life Science, Institute for Innovative Research, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama 226-8503, Japan
| | - Tadashi Suzuki
- Department of Chemistry and Biological Science, Aoyama Gakuin University, 5-10-1 Fuchinobe, Sagamihara, Kanagawa 252-5258, Japan
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Muramatsu S, Ohshimo K, Shi Y, Kida M, Shang R, Yamamoto Y, Misaizu F, Inokuchi Y. Gas-Phase Characterization of Hypervalent Carbon Compounds Bearing 7-6-7-Ring Skeleton: Penta- versus Tetra-Coordinate Isomers. Chemistry 2023; 29:e202203163. [PMID: 36417203 DOI: 10.1002/chem.202203163] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2022] [Revised: 11/14/2022] [Accepted: 11/23/2022] [Indexed: 11/24/2022]
Abstract
In this study, we afford explicit characterizations of the electronic and geometrical structures of recently reported hypervalent penta-coordinate carbon compounds by using gas-phase characterization techniques: photodissociation spectroscopy (PDS) and ion mobility-mass spectrometry (IM-MS). In particular for a compound with moderately electron-donating ligands, bearing p-methylthiophenyl substituents, the coexistence of tetra- and penta-coordinate isomers is confirmed, consistent with solution characterizations. It is in sharp contrast to the exclusive tetra-coordinate form (with normal valence of the central carbon atom) in the single crystal. This suggests that a non-polar environment makes the penta-coordinate structure thermodynamically most stable. This delicate difference between the tetra- and penta-coordinate structures, which depends on the environment, is a close reflection of the lower activation barrier of the SN 2 reaction found in neutral solvent or gas-phase reactions.
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Affiliation(s)
- Satoru Muramatsu
- Department of Chemistry, Graduate School of Advanced Science and Engineering, Hiroshima University, 1-3-1 Kagamiyama, Higashi, Hiroshima, 739-8526, Japan
| | - Keijiro Ohshimo
- Department of Chemistry, Graduate School of Science, Tohoku University, 6-3 Aoba, Aramaki, Aoba-ku, Sendai, 980-8578, Japan
| | - Yuan Shi
- Department of Chemistry, Graduate School of Advanced Science and Engineering, Hiroshima University, 1-3-1 Kagamiyama, Higashi, Hiroshima, 739-8526, Japan
| | - Motoki Kida
- Department of Chemistry, Graduate School of Advanced Science and Engineering, Hiroshima University, 1-3-1 Kagamiyama, Higashi, Hiroshima, 739-8526, Japan
| | - Rong Shang
- Department of Chemistry, Graduate School of Advanced Science and Engineering, Hiroshima University, 1-3-1 Kagamiyama, Higashi, Hiroshima, 739-8526, Japan
| | - Yohsuke Yamamoto
- Department of Chemistry, Graduate School of Advanced Science and Engineering, Hiroshima University, 1-3-1 Kagamiyama, Higashi, Hiroshima, 739-8526, Japan
| | - Fuminori Misaizu
- Department of Chemistry, Graduate School of Science, Tohoku University, 6-3 Aoba, Aramaki, Aoba-ku, Sendai, 980-8578, Japan
| | - Yoshiya Inokuchi
- Department of Chemistry, Graduate School of Advanced Science and Engineering, Hiroshima University, 1-3-1 Kagamiyama, Higashi, Hiroshima, 739-8526, Japan
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Muramatsu S, Tokizane T, Inokuchi Y. One-Dimensionally Conjugated Carbocyanine Dyes Isolated under Cold Gas-Phase Conditions: Electronic Spectra and Photochemistry. J Phys Chem A 2022; 126:8127-8135. [DOI: 10.1021/acs.jpca.2c05111] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Satoru Muramatsu
- Department of Chemistry, Graduate School of Advanced Science and Engineering, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima-shi, Hiroshima739-8526, Japan
| | - Takayuki Tokizane
- Department of Chemistry, Graduate School of Advanced Science and Engineering, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima-shi, Hiroshima739-8526, Japan
| | - Yoshiya Inokuchi
- Department of Chemistry, Graduate School of Advanced Science and Engineering, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima-shi, Hiroshima739-8526, Japan
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