1
|
Conformational Structures of Neutral and Cationic Pivaldehyde Revealed by IR-Resonant VUV-MATI Mass Spectroscopy. Int J Mol Sci 2022; 23:ijms232314777. [PMID: 36499105 PMCID: PMC9735833 DOI: 10.3390/ijms232314777] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Revised: 11/22/2022] [Accepted: 11/23/2022] [Indexed: 11/29/2022] Open
Abstract
Pivaldehyde, which is an unwanted by-product released with engine exhaust, has received considerable research attention because of its hydrocarbon oxidations at atmospheric temperature. To gain insight into the conformer-specific reaction dynamics, we investigated the conformational structures of the pivaldehyde molecule in neutral (S0) and cationic (D0) states using the recently invented IR-resonant VUV-MATI mass spectroscopy. Additionally, we constructed the two-dimensional potential energy surfaces (2D PESs) associated with the conformational transformations in the S0 and D0 states to deduce the conformations corresponding to the measured vibrational spectra. The 2D PESs indicated the presence of only the eclipsed conformation in the global minima of both states, unlike those in propanal and isobutanal. However, comparing the IR-dip VUV-MATI spectra from two intense peaks in the VUV-MATI spectrum with the anharmonic IR simulations revealed the correspondence between the gauche conformer on the S0 state and the measured IR spectra. Furthermore, Franck-Condon analysis confirmed that most peaks in the VUV-MATI spectrum are attributed to the adiabatic ionic transitions between the neutral gauche and cationic eclipsed conformers in pivaldehyde. Consequently, electron removal from the highest occupied molecular orbital, consisting of the nonbonding orbital of the oxygen atom in pivaldehyde, promoted the formyl-relevant modes in the induced cationic eclipsed conformer.
Collapse
|
2
|
Min A, Kim J, Moon CJ, Ahn A, Park J, Choi MY. Spectroscopic and theoretical studies of jet‐cooled 3‐cyanoindole ammonia clusters in the gas phase. B KOREAN CHEM SOC 2022. [DOI: 10.1002/bkcs.12502] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Ahreum Min
- Core‐Facility Center for Photochemistry & Nanomaterials Gyeongsang National University Jinju Republic of Korea
| | - Jiwon Kim
- Department of Chemistry (BK21 FOUR), Research Institute of Natural Sciences Gyeongsang National University Jinju Republic of Korea
| | - Cheol Joo Moon
- Department of Chemistry (BK21 FOUR), Research Institute of Natural Sciences Gyeongsang National University Jinju Republic of Korea
| | - Ahreum Ahn
- Center for Supercomputing Applications Korea Institute of Science and Technology Information Daejeon Republic of Korea
| | - Juhyeon Park
- Department of Chemistry (BK21 FOUR), Research Institute of Natural Sciences Gyeongsang National University Jinju Republic of Korea
| | - Myong Yong Choi
- Core‐Facility Center for Photochemistry & Nanomaterials Gyeongsang National University Jinju Republic of Korea
- Department of Chemistry (BK21 FOUR), Research Institute of Natural Sciences Gyeongsang National University Jinju Republic of Korea
| |
Collapse
|
3
|
Park SM, Kwon CH. Identification of individual conformers in C 4H 6O isomers using conformer-specific vibrational spectroscopy. RSC Adv 2021; 11:38240-38246. [PMID: 35498109 PMCID: PMC9044234 DOI: 10.1039/d1ra07397d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2021] [Accepted: 11/23/2021] [Indexed: 11/21/2022] Open
Abstract
We measured the conformer-specific vibrational spectra of C4H6O isomers in neutral and cationic states using IR resonant vacuum ultraviolet mass-analyzed threshold ionization (VUV-MATI) spectroscopy for the first time. Notably, the measured IR dip and hole-burn VUV-MATI spectra for each isomer represent the identifiable vibrational spectra of individual conformers in both states. Furthermore, we estimated the relative populations of individual conformers in crotonaldehyde (CA) and methyl vinyl ketone (MVK) isomers using the IR dip intensity, the corresponding Franck-Condon factor, and the IR absorption cross section. Our analysis revealed that the compositional ratio of s-trans to s-cis conformers in the CA isomer remained at 95.8 : 4.2 even under supersonic expansion, whereas that in the MVK isomer was determined as 90.6 : 9.4, which is consistent with previous research. These findings reveal that the conformational stability of each isomer depends on the position of the methyl group relative to the carbonyl group.
Collapse
Affiliation(s)
- Sung Man Park
- Department of Chemistry, Institute for Molecular Science and Fusion Technology, Kangwon National University Chuncheon 24341 Korea
| | - Chan Ho Kwon
- Department of Chemistry, Institute for Molecular Science and Fusion Technology, Kangwon National University Chuncheon 24341 Korea
| |
Collapse
|
4
|
Park SM, Kwon CH. Development and Verification of Conformer-Specific Vibrational Spectroscopy. J Phys Chem A 2021; 125:9251-9258. [PMID: 34628860 DOI: 10.1021/acs.jpca.1c07162] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Conformers have similar vibrational structures both in neutral (S0) and cationic (D0) states owing to the comparable force fields between their nuclei. Nevertheless, there is a continuous development of vibrational spectroscopic techniques to rigorously identify individual conformers in the designated molecule but only in the S0 state. We developed an inventive conformer-specific vibrational spectroscopic technique to measure identifiable vibrational spectra of individual conformers in both S0 and D0 states. We measured isomer-specific vibrational spectra in both states for gas-phase acetone and oxetane isomers from a solution with azeotropic composition to verify the proposed techniques that are based on infrared (IR) resonant vacuum ultraviolet mass-analyzed threshold ionization (VUV-MATI) spectroscopy. The measured IR dip VUV-MATI and IR hole-burn VUV-MATI spectra for each isomer, which correspond to isomer-specific vibrational spectra in both states, can be represented by IR-resonant VUV photoionization and one-photon VUV-MATI spectra of the binary mixture, respectively, under supersonic expansion conditions. The partial pressures of the individual isomers in the binary mixture with different mole fractions estimated according to the relative peak intensities in the measured spectra provide insights on solute-solvent interactions. We suggest that the verified IR-resonant VUV-MATI spectroscopy can form the basis of effective schemes toward conformational chemistry.
Collapse
Affiliation(s)
- Sung Man Park
- Department of Chemistry and Institute for Molecular Science and Fusion Technology, Kangwon National University, Chuncheon 24341, Korea
| | - Chan Ho Kwon
- Department of Chemistry and Institute for Molecular Science and Fusion Technology, Kangwon National University, Chuncheon 24341, Korea
| |
Collapse
|
5
|
Hong A, Min A, Jang H, Moon CJ, Jeong C, Choi MY, Heo J, Kim NJ. Induced Circular Dichroism of Jet-Cooled Phenol Complexes with ( R)-(-)-2-Butanol. J Phys Chem A 2019; 123:8913-8920. [PMID: 31549840 DOI: 10.1021/acs.jpca.9b07237] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The induced circular dichroism (ICD) of phenol complexed with (R)-(-)-2-butanol [PhOH-(-)BOH] in a supersonic jet is investigated using resonant two-photon ionization circular dichroism (R2PICD) spectroscopy. The R2PICD spectrum of PhOH-(-)BOH exhibits nonzero ICD bands near the absorption region of bare PhOH, where (-)BOH is transparent. Two different conformers containing a single hydrogen bond between PhOH and (-)BOH are identified using ultraviolet-ultraviolet hole-burning and infrared ion-dip spectroscopy combined with quantum theoretical calculations. The ICD values of the two conformers are similar to each other. To understand these similar ICD effects of the conformers, the geometrical asymmetry of the PhOH moiety bound to (-)BOH and the coupling strength of the electric transition dipole moments between PhOH and (-)BOH are estimated. Comparing the ICD values of PhOH-(-)BOH with those of PhOH-(-)-l-methyl lactate in the previous report [ Hong , A. ; J. Phys. Chem. Lett. 2018 , 9 , 476 -480 ], we investigate the physical properties that may govern the differences of the ICD values between the two complexes.
Collapse
Affiliation(s)
- Aram Hong
- Department of Chemistry , Chungbuk National University , Cheongju , Chungbuk 28644 , Korea
| | - Ahreum Min
- Department of Chemistry , Chungbuk National University , Cheongju , Chungbuk 28644 , Korea
| | - Heeseon Jang
- Department of Chemistry , Chungbuk National University , Cheongju , Chungbuk 28644 , Korea
| | - Cheol Joo Moon
- Department of Chemistry (BK21+) and Research Institute of Natural Science , Gyeongsang National University , Jinju 52828 , Korea
| | - Changseop Jeong
- Department of Chemistry , Chungbuk National University , Cheongju , Chungbuk 28644 , Korea
| | - Myong Yong Choi
- Department of Chemistry (BK21+) and Research Institute of Natural Science , Gyeongsang National University , Jinju 52828 , Korea
| | - Jiyoung Heo
- Department of Green Chemical Engineering , Sangmyung University , Cheonan , Chungnam 31066 , Korea
| | - Nam Joon Kim
- Department of Chemistry , Chungbuk National University , Cheongju , Chungbuk 28644 , Korea
| |
Collapse
|
6
|
Zhao Y, Jin Y, Hao J, Yang Y, Wang L, Li C, Jia S. Rotamers of p‑isopropylphenol studied by hole-burning resonantly enhanced multiphoton ionization and mass analyzed threshold ionization spectroscopy. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2019; 207:328-336. [PMID: 30268901 DOI: 10.1016/j.saa.2018.09.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Revised: 09/05/2018] [Accepted: 09/08/2018] [Indexed: 06/08/2023]
Abstract
The resonance enhanced multiphoton ionization (REMPI), ultraviolet-ultraviolet (UV-UV) hole burning and mass analyzed threshold ionization (MATI) spectroscopy have been applied to investigate the vibrational features of p‑isopropylphenol in its first electronically excited state S1 and cationic ground state D0. Two stable conformational structures of p‑isopropylphenol are distinctly found in the supersonic molecular beam and identified as the cis and trans rotamers through REMPI and UV-UV hole burning spectroscopy. The electronic excitation energies of S1 ← S0 transition of two rotamers are determined to be 35,578 and 35,593 cm-1, and the adiabatic ionization energies are 65,331 and 65,350 cm-1, respectively. The MATI spectra recorded via different intermediate levels of S1 state indicate the similarity in the molecular geometry between the S1 state and the D0 state for each rotamer of p‑isopropylphenol. Geometrical optimizations of p‑isopropylphenol have also been performed using the density functional theory (DFT) for S0 and D0 states, and time-dependent density functional theory (TDDFT) for S1 state. The simulated spectra for S1 ← S0 and D0 ← S1 transitions of two rotamers are able to reproduce qualitatively the experimental spectral profile, which help us to assign the vibronic modes. Most of the observed vibrations of two rotamers in the S1 and D0 states are related to the in-plane ring deformation and some active modes involving isopropyl group.
Collapse
Affiliation(s)
- Yan Zhao
- State Key Laboratory of Quantum Optics and Quantum Optic Devices, Institute of Laser Spectroscopy, Shanxi University, Taiyuan, Shanxi 030006, China
| | - Yinghui Jin
- State Key Laboratory of Quantum Optics and Quantum Optic Devices, Institute of Laser Spectroscopy, Shanxi University, Taiyuan, Shanxi 030006, China
| | - Jiayu Hao
- State Key Laboratory of Quantum Optics and Quantum Optic Devices, Institute of Laser Spectroscopy, Shanxi University, Taiyuan, Shanxi 030006, China
| | - Yonggang Yang
- State Key Laboratory of Quantum Optics and Quantum Optic Devices, Institute of Laser Spectroscopy, Shanxi University, Taiyuan, Shanxi 030006, China; Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, Shanxi 030006, China
| | - Lirong Wang
- State Key Laboratory of Quantum Optics and Quantum Optic Devices, Institute of Laser Spectroscopy, Shanxi University, Taiyuan, Shanxi 030006, China; Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, Shanxi 030006, China
| | - Changyong Li
- State Key Laboratory of Quantum Optics and Quantum Optic Devices, Institute of Laser Spectroscopy, Shanxi University, Taiyuan, Shanxi 030006, China; Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, Shanxi 030006, China.
| | - Suotang Jia
- State Key Laboratory of Quantum Optics and Quantum Optic Devices, Institute of Laser Spectroscopy, Shanxi University, Taiyuan, Shanxi 030006, China; Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, Shanxi 030006, China
| |
Collapse
|
7
|
Kim Y, Kim J, Baek KY, Kim WY. Efficient structural elucidation of microhydrated biomolecules through the interrogation of hydrogen bond networks. Phys Chem Chem Phys 2018. [DOI: 10.1039/c7cp08372f] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Pattern analysis of H-bond networks through a graph-theoretic method is very effective in determining the global minima of microhydrated biomolecules.
Collapse
Affiliation(s)
| | - Jaewook Kim
- Department of Chemistry
- KAIST
- Daejeon 34141
- Korea
| | | | | |
Collapse
|
8
|
Moon CJ, Ahn A, Min A, Seong YG, Kim JH, Choi MY. Conformationally resolved spectroscopy of jet-cooled methacetin. Chem Phys Lett 2017. [DOI: 10.1016/j.cplett.2017.09.049] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
|
9
|
Choe JC, Moon CJ, Choi MY, Kim MH. Photodissociation kinetics of the isobutanal radical cation: a combined experimental and theoretical study. RSC Adv 2017. [DOI: 10.1039/c7ra08526e] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Main photodissociation pathways of isobutanal radical cation generated by (2 + 1) REMPI process.
Collapse
Affiliation(s)
- Joong Chul Choe
- Department of Chemistry
- Dongguk University-Seoul
- Seoul 04620
- Korea
| | - Cheol Joo Moon
- Department of Chemistry(BK21+)
- Research Institute of Natural Science
- Gyeongsang National University
- JinJu 52828
- Korea
| | - Myong Yong Choi
- Department of Chemistry(BK21+)
- Research Institute of Natural Science
- Gyeongsang National University
- JinJu 52828
- Korea
| | - Myung Hwa Kim
- Department of Chemistry & Nano Science
- Ewha Womans University
- Seoul 03760
- Korea
| |
Collapse
|