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Ito R, Ohshimo K, Misaizu F. Intra-host π-π interactions in crown ether complexes revealed by cryogenic ion mobility-mass spectrometry. Phys Chem Chem Phys 2024; 26:12537-12544. [PMID: 38619106 DOI: 10.1039/d4cp00835a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/16/2024]
Abstract
Cryogenic ion mobility-mass spectrometry was performed to investigate the relative abundance of conformers of dinaphtho-24-crown-8 (DN24C8) complexes with alkali metal cations M+ (M = Li, Na, K, Rb, and Cs). The "closed" conformers of M+(DN24C8) with short distances between two naphthalene rings in the crown ethers were predominantly observed for all complexes at 86 K. The two noncovalent interactions, host-guest and intra-host interactions, were analyzed separately by density functional theory calculations to reveal the origin of the stability of the closed conformers. As a result, it was revealed that the intra-host π-π interactions have a more critical role in determining the stability of the conformers than the host-guest interactions. The closed conformers of M+(DN24C8) also have wider regions of the π-π interactions than those of the M+(dibenzo-24-crown-8) complexes.
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Affiliation(s)
- Ryosuke Ito
- Department of Chemistry, Graduate School of Science, Tohoku University, Sendai 980-8578, Japan.
| | - Keijiro Ohshimo
- Department of Chemistry, Graduate School of Science, Tohoku University, Sendai 980-8578, Japan.
| | - Fuminori Misaizu
- Department of Chemistry, Graduate School of Science, Tohoku University, Sendai 980-8578, Japan.
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Mubas-Sirah F, Gandhi VD, Latif M, Hua L, Tootchi A, Larriba-Andaluz C. Ion mobility calculations of flexible all-atom systems at arbitrary fields using two-temperature theory. Phys Chem Chem Phys 2024; 26:4118-4124. [PMID: 38226667 DOI: 10.1039/d3cp05415b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2024]
Abstract
Ion mobility spectrometry (IMS) separates and analyzes ions based on their mobility in a gas under an electric field. When the field is increased, the mobility varies in a complex way that depends on the relative velocity between gas and ion, their electrostatic potential interactions, and the effects from direct impingement. Recently, the two-temperature theory, primarily developed for monoatomic ions in monoatomic gases, has been extended to study mobilities at arbitrary fields using polyatomic ions in polyatomic gases, with some success. However, this extension poses challenges, such as inelastic collisions between gas and ion and structural modifications of ions as they heat up. These challenges become significant when working with diatomic gases and flexible molecules. In a previous study, experimental mobilities of tetraalkylammonium salts were obtained using a FAIMS instrument, showing satisfactory agreement with numerical two-temperature theory predictions. However, deviations occurred at fields greater than 100 Td. To address this issue, this paper introduces a modified high-field calculation method that accounts for the structural changes in ions due to field heating. The study focuses on tetraheptylammonium (THA+), tetradecylammonium (TDA+), and tetradodecylammonium (TDDA+) salts. Molecular structures were generated at various temperatures using MM2 forcefield. The mobility was calculated using IMoS 1.13 with two-temperature trajectory method calculations up to the fourth approximation. Multiple effective temperatures were considered, and a linear weighing system was used to create mobility vs. reduced field strength plots. The results suggest that the structural enlargement due to ion heating plays a significant role in mobility at high fields, aligning better with experimental data. FAIMS' dispersion plots also show improved agreement with experimental results. However, the contribution of inelastic collisions and energy transfer to rotational degrees of freedom in gas molecules remains a complex and challenging aspect.
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Affiliation(s)
- Farah Mubas-Sirah
- Department of Mechanical Engineering, Indiana University - Purdue University Indianapolis, Indianapolis, IN, USA.
| | - Viraj D Gandhi
- Department of Mechanical Engineering, Indiana University - Purdue University Indianapolis, Indianapolis, IN, USA.
- Department of Mechanical Engineering, Purdue University, West Lafayette, IN, USA
| | - Mohsen Latif
- Department of Mechanical Engineering, Indiana University - Purdue University Indianapolis, Indianapolis, IN, USA.
| | - Leyan Hua
- Department of Mechanical Engineering, Indiana University - Purdue University Indianapolis, Indianapolis, IN, USA.
| | - Amirreza Tootchi
- Department of Mechanical Engineering, Indiana University - Purdue University Indianapolis, Indianapolis, IN, USA.
| | - Carlos Larriba-Andaluz
- Department of Mechanical Engineering, Indiana University - Purdue University Indianapolis, Indianapolis, IN, USA.
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Ohshimo K, Sato R, Takasaki Y, Tsunoda K, Ito R, Kanno M, Misaizu F. Highly Efficient Intramolecular Proton Transfer in p-Aminobenzoic Acid by a Single Ammonia Molecule as a Vehicle. J Phys Chem Lett 2023; 14:8281-8288. [PMID: 37677142 DOI: 10.1021/acs.jpclett.3c01996] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/09/2023]
Abstract
Proton transfer is classified into two mechanisms: the Grotthuss (proton-relay) and vehicle mechanisms. It has been well studied on gas-phase proton transfer by a proton relay involving multiple molecules. However, a vehicle mechanism in which a single molecule transports a proton has rarely been reported. Here, we have obtained clear evidence that the proton transfers efficiently between the two protonation sites in protonated p-aminobenzoic acid (PABA·H+) by a single ammonia molecule as a vehicle. The gaseous PABA·H+ ions were reacted with NH3 or ND3 under single-collision conditions in a cold ion trap, and the proton-transferred ions were identified by cryogenic ion mobility-mass spectrometry. A reaction intermediate PABA·H+·NH3 was also detected for the first time. The reaction pathway search calculations and ab initio molecular dynamics simulations supported the present experimental finding that intramolecular proton transfer occurs very efficiently by the vehicle mechanism.
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Affiliation(s)
- Keijiro Ohshimo
- Department of Chemistry, Graduate School of Science, Tohoku University, Sendai 980-8578, Japan
| | - Ryosuke Sato
- Department of Chemistry, Graduate School of Science, Tohoku University, Sendai 980-8578, Japan
| | - Yuya Takasaki
- Department of Chemistry, Graduate School of Science, Tohoku University, Sendai 980-8578, Japan
| | - Kengo Tsunoda
- Department of Chemistry, Graduate School of Science, Tohoku University, Sendai 980-8578, Japan
| | - Ryosuke Ito
- Department of Chemistry, Graduate School of Science, Tohoku University, Sendai 980-8578, Japan
| | - Manabu Kanno
- Department of Chemistry, Graduate School of Science, Tohoku University, Sendai 980-8578, Japan
| | - Fuminori Misaizu
- Department of Chemistry, Graduate School of Science, Tohoku University, Sendai 980-8578, 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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Ito R, He X, Ohshimo K, Misaizu F. Large Conformational Change in the Isomerization of Flexible Crown Ether Observed at Low Temperature. J Phys Chem A 2022; 126:4359-4366. [PMID: 35786937 DOI: 10.1021/acs.jpca.2c02271] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The dynamic processes of conformational changes of supramolecules are important to understand the motion in synthetic supramolecules. Although a host-guest complex is the most basic supramolecule, a detailed mechanism of its conformational changes has rarely been studied. Here, we observed the large conformational change of a dibenzo-24-crown-8 complex with four guest ions (Ag+, Na+, K+, and NH4+) at low temperature in the gas phase. The isomerization between the two types of conformers, which have different distances between the two benzene rings, proceeds even at 86 K. Using variable-temperature ion mobility-mass spectrometry (IM-MS) at 100-210 K, the activation energy for the isomerization is determined to be rather small (4.8-9.0 kJ mol-1). Reaction pathway calculations revealed that the isomerization is caused by the sequential rotation of two single bonds in the crown ether ring. The present cryogenic IM-MS study of the host-guest complexes at the molecular level opens an approach to detailed understanding of the motion in supramolecules.
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Affiliation(s)
- Ryosuke Ito
- Department of Chemistry, Graduate School of Science, Tohoku University, 6-3 Aoba, Aramaki, Aoba-ku, Sendai 980-8578, Japan
| | - Xi He
- Department of Chemistry, Graduate School of Science, Tohoku University, 6-3 Aoba, Aramaki, Aoba-ku, Sendai 980-8578, Japan
| | - Keijiro Ohshimo
- Department of Chemistry, Graduate School of Science, Tohoku University, 6-3 Aoba, Aramaki, Aoba-ku, Sendai 980-8578, Japan
| | - Fuminori Misaizu
- Department of Chemistry, Graduate School of Science, Tohoku University, 6-3 Aoba, Aramaki, Aoba-ku, Sendai 980-8578, Japan
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Ito R, Ohshimo K, Misaizu F. Structures of dibenzo-24-crown-8 complex with an NH4+ ion studied by cryogenic ion mobility-mass spectrometry. Chem Phys Lett 2022. [DOI: 10.1016/j.cplett.2022.139510] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Ohshimo K, He X, Ito R, Misaizu F. Conformer Separation of Dibenzo-Crown-Ether Complexes with Na + and K + Ions Studied by Cryogenic Ion Mobility-Mass Spectrometry. J Phys Chem A 2021; 125:3718-3725. [PMID: 33904306 DOI: 10.1021/acs.jpca.1c02300] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We performed cryogenic ion mobility-mass spectrometry (IM-MS) to study conformations of dibenzo-crown-ether complexes with Na+ and K+ ions at 86 K in the gas phase. Four dibenzo-crown-ethers (dibenzo-18-crown-6, dibenzo-21-crown-7, dibenzo-24-crown-8, and dibenzo-30-crown-10) with different cavity ring sizes were investigated. For dibenzo-18-crown-6 complexes with Na+ and K+, only one type of conformer was assigned by comparing the experimental collision cross sections with those predicted theoretically for candidate structures. In this conformer, the distance between two benzene rings in the complexes was long due to the open form of the dibenzo-18-crown-6. This open conformer was consistent with the previous laser spectroscopic studies of the cold complex ions in the gas phase. For dibenzo-21-crown-7 and dibenzo-24-crown-8 complexes with Na+ and K+, two types of conformers were clearly separated by IM-MS. These two conformer types were assigned to "open" and "closed" forms in which benzene-benzene distances were long and short, respectively. Observed relative abundances of the open and closed conformers qualitatively agreed with the Boltzmann distribution using Gibbs energies of the conformers calculated by quantum chemical calculations. For the Na+(dibenzo-30-crown-10) complex, open and closed conformers were also observed in IM-MS. On the other hand, only the closed conformer was observed for the K+(dibenzo-30-crown-10) complex. This closed conformer was similar to the "wraparound" structure, which was proposed in the previous studies in the solution. In conclusion, the closed conformers were formed by the deformation of flexible crown ethers with large cavity ring sizes. In addition, the diameter of the K+ ion was suitable to form the closed conformer by deformation of the molecular structure of dibenzo-30-crown-10.
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Affiliation(s)
- Keijiro Ohshimo
- Department of Chemistry, Graduate School of Science, Tohoku University, 6-3 Aoba, Aramaki, Aoba-ku, Sendai 980-8578, Japan
| | - Xi He
- Department of Chemistry, Graduate School of Science, Tohoku University, 6-3 Aoba, Aramaki, Aoba-ku, Sendai 980-8578, Japan
| | - Ryosuke Ito
- Department of Chemistry, Graduate School of Science, Tohoku University, 6-3 Aoba, Aramaki, Aoba-ku, Sendai 980-8578, Japan
| | - Fuminori Misaizu
- Department of Chemistry, Graduate School of Science, Tohoku University, 6-3 Aoba, Aramaki, Aoba-ku, Sendai 980-8578, Japan
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Tainaka S, Ujihira T, Kubo M, Kida M, Shimoyama D, Muramatsu S, Abe M, Haino T, Ebata T, Misaizu F, Ohshimo K, Inokuchi Y. Conformation of K+(Crown Ether) Complexes Revealed by Ion Mobility–Mass Spectrometry and Ultraviolet Spectroscopy. J Phys Chem A 2020; 124:9980-9990. [DOI: 10.1021/acs.jpca.0c09068] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Sota Tainaka
- Department of Chemistry, Graduate School of Science, Tohoku University, Sendai 980-8578, Japan
| | - Tomoyuki Ujihira
- Department of Chemistry, Graduate School of Science, Hiroshima University, Higashi-Hiroshima 739-8526, Japan
| | - Mayuko Kubo
- Department of Chemistry, Graduate School of Science, Hiroshima University, Higashi-Hiroshima 739-8526, Japan
| | - Motoki Kida
- Department of Chemistry, Graduate School of Science, Hiroshima University, Higashi-Hiroshima 739-8526, Japan
| | - Daisuke Shimoyama
- Department of Chemistry, Graduate School of Science, Hiroshima University, Higashi-Hiroshima 739-8526, Japan
| | - Satoru Muramatsu
- Department of Chemistry, Graduate School of Science, Hiroshima University, Higashi-Hiroshima 739-8526, Japan
| | - Manabu Abe
- Department of Chemistry, Graduate School of Science, Hiroshima University, Higashi-Hiroshima 739-8526, Japan
| | - Takeharu Haino
- Department of Chemistry, Graduate School of Science, Hiroshima University, Higashi-Hiroshima 739-8526, Japan
| | - Takayuki Ebata
- Department of Chemistry, Graduate School of Science, Hiroshima University, Higashi-Hiroshima 739-8526, Japan
| | - Fuminori Misaizu
- Department of Chemistry, Graduate School of Science, Tohoku University, Sendai 980-8578, Japan
| | - Keijiro Ohshimo
- Department of Chemistry, Graduate School of Science, Tohoku University, Sendai 980-8578, Japan
| | - Yoshiya Inokuchi
- Department of Chemistry, Graduate School of Science, Hiroshima University, Higashi-Hiroshima 739-8526, Japan
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