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Carlson CD, Ma J, Al-Jabiri MH, Insausti A, Xu Y. Conformational adaptation and large amplitude motions of 1-phenyl-2,2,2-trifluoroethanol with two water molecules: a rotational spectroscopic and ab initio investigation. Phys Chem Chem Phys 2024; 26:18067-18075. [PMID: 38895791 DOI: 10.1039/d4cp01516a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/21/2024]
Abstract
The 1 : 2 adduct of 1-phenyl-2,2,2-trifluoroethanol (PhTFE), a chiral fluoroalcohol, with two water molecules (PhTFE⋯2H2O) was investigated via chirped pulse Fourier-transform microwave (CP-FTMW) spectroscopy and theoretical calculations. A systematic search of the PhTFE⋯2H2O conformational landscape identified 38 stable minima at the B3LYP-D3BJ/def2-TZVPPD level of theory, 27 of which are within an energy window of 10 kJ mol-1 after applying zero-point energy corrections. Rotational spectra of a single PhTFE⋯2H2O conformer along with eight deuterated and three oxygen-18 isotopologues were assigned. Interestingly, the observed PhTFE⋯2H2O conformer contains PhTFE II, the second most stable monomer conformer, and the most stable PhTFE I dihydrate is ca. 4 kJ mol-1 higher in energy. In contrast, PhTFE I⋯H2O was identified experimentally and theoretically as the most stable 1 : 1 conformer. Furthermore, the observed dihydrate structure experiences large amplitude motions connecting three theoretical minima which differ only in which water oxygen lone pairs are involved in the hydrogen-bonds, i.e., the free OH pointing directions. Additionally, the ortho and para-H2O tunnelling splittings were detected and attributed to the interchange water hydrogen atoms which interact with the aromatic part of PhTFE but not for the water interacting with PhTFE hydroxy group. Extensive theoretical modelling was carried out to gain insight into the associated large amplitude motions including tunnelling, supported by the experimental isotopic and tunnelling splitting data.
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Affiliation(s)
- Colton D Carlson
- Department of Chemistry, University of Alberta, Edmonton, AB, T6G 2G2, Canada.
| | - Jiarui Ma
- Department of Chemistry, University of Alberta, Edmonton, AB, T6G 2G2, Canada.
| | - Mohamad H Al-Jabiri
- Department of Chemistry, University of Alberta, Edmonton, AB, T6G 2G2, Canada.
| | - Aran Insausti
- Department of Chemistry, University of Alberta, Edmonton, AB, T6G 2G2, Canada.
- Departamento de Quimica Física, Facultad de Ciencia y Tecnología, Universidad del País Vasco (UPV-EHU), Bilbao 48080, Spain
- Biofisika Institute (CSIC, UPV/EHU), University of the Basque Country (UPV/EHU), Leioa 48940, Spain
| | - Yunjie Xu
- Department of Chemistry, University of Alberta, Edmonton, AB, T6G 2G2, Canada.
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King NJ, LeBlanc ID, Brown A. A variant on the CREST iMTD algorithm for noncovalent clusters of flexible molecules. J Comput Chem 2024. [PMID: 38944673 DOI: 10.1002/jcc.27458] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2024] [Revised: 05/15/2024] [Accepted: 06/12/2024] [Indexed: 07/01/2024]
Abstract
Conformational ensemble generation and the search for the global minimum conformation are important problems in computational chemistry. In this work, a variant on the conformer-rotamer ensemble sampling tool (CREST) iterative metadynamics (iMTD) algorithm designed for determining structural ensembles and energetics of noncovalent clusters of flexible molecules is presented. We term this new algorithm a low-energy diversity-enhanced variant on CREST, or LEDE-CREST. As with CREST, the energies are evaluated using the semiempirical GFN2-xTB extended tight binding approach. The utility of the algorithm is highlighted by generating ensembles for a variety of noncovalent clusters of flexible or rigid monomers using both CREST and LEDE-CREST.
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Affiliation(s)
- Nathanael J King
- Department of Chemistry, University of Alberta, Edmonton, Canada
| | - Ian D LeBlanc
- Department of Computer Science, Grant MacEwan University, Edmonton, Canada
| | - Alex Brown
- Department of Chemistry, University of Alberta, Edmonton, Canada
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Yang Y, Krin A, Cai X, Poopari MR, Zhang Y, Cheeseman JR, Xu Y. Conformations of Steroid Hormones: Infrared and Vibrational Circular Dichroism Spectroscopy. Molecules 2023; 28:molecules28020771. [PMID: 36677830 PMCID: PMC9864676 DOI: 10.3390/molecules28020771] [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: 12/25/2022] [Revised: 01/09/2023] [Accepted: 01/10/2023] [Indexed: 01/13/2023] Open
Abstract
Steroid hormone molecules may exhibit very different functionalities based on the associated functional groups and their 3D arrangements in space, i.e., absolute configurations and conformations. Infrared (IR) and vibrational circular dichroism (VCD) spectra of four different steroid hormones, namely dehydroepiandrosterone (DHEA), 17α-methyltestosterone (MTTT), (16α,17)-epoxyprogesterone (Epoxy-P4), and dehydroepiandrosterone acetate (AcO-DHEA), were measured in deuterated dimethyl sulfoxide and some also in carbon tetrachloride. Extensive conformational searches were carried out using the recent developed conformer-rotamer ensemble sampling tool (CREST) which also accounts for solvent effects using an implicit solvation model. All the CREST conformational candidates were then reoptimized at the B3LYP-D3BJ/def2-TZVPD with the PCM of solvent. The good agreements between the experimental IR and VCD spectra and the theoretical simulations provide a conclusive information about their conformational distribution and absolute configurations. The experimental and theoretical IR and VCD spectra of AcO-DHEA in the carbonyl and alkene stretching region showed some discrepancies, and the possible causes related to solvent effects, large amplitude motions and levels of theory used in the modelling were explored in detail. As part of the investigation, additional calculations at the B3LYP-D3BJ/6-31++G (2d,p) and B3LYP-D3BJ/cc-pVTZ levels, as well as some 'mixed' calculations with the double-hybrid functional B2PLYP-D3 were also carried out. The results indicate that the double-hybrid functional is important for predicting the correct IR band pattern in the carbonyl and alkene stretching region.
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Affiliation(s)
- Yanqing Yang
- Department of Chemistry, University of Alberta, Edmonton, AB T6G 2G2, Canada
| | - Anna Krin
- Department of Chemistry, University of Alberta, Edmonton, AB T6G 2G2, Canada
- Centre for Science and Peace Research (ZNF), Universität Hamburg, Bogenallee 11, 20144 Hamburg, Germany
| | - Xiaoli Cai
- Department of Chemistry, University of Alberta, Edmonton, AB T6G 2G2, Canada
- Key Laboratory for Green Chemical Process of Ministry of Education, Wuhan Institute of Technology, Wuhan 430073, China
| | | | - Yuefei Zhang
- Key Laboratory for Green Chemical Process of Ministry of Education, Wuhan Institute of Technology, Wuhan 430073, China
| | - James R. Cheeseman
- Gaussian Inc., 340 Quinnipiac St., Bldg., 40, Wallingford, CT 06492-4050, USA
| | - Yunjie Xu
- Department of Chemistry, University of Alberta, Edmonton, AB T6G 2G2, Canada
- Correspondence: ; Tel.: +1-780-402-1244
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4
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Zheng Y, Chen J, Duan C, Zhang X, Xu X, Gou Q. Accurate Geometry and Non-Covalent Interactions in 1-Phenylethanol and Its Monohydrate: A Rotational Study. Chemphyschem 2022; 24:e202200804. [PMID: 36537871 DOI: 10.1002/cphc.202200804] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Revised: 12/15/2022] [Accepted: 12/16/2022] [Indexed: 12/24/2022]
Abstract
The pure rotational spectra of 1-phenylethanol and its monohydrate were measured by using a pulsed jet Fourier transform microwave spectrometer. One conformer of the 1-phenylethanol monomer with the trans form was observed in the pulsed jet. The experimental values of rotational constants of ten isotopologues, including eight mono-substituted 13 C and one D isotopologues, allow an accurate structure determination of the skeleton of 1-phenylethanol. For its monohydrate, only one isomer has been observed, of which 1-phenylethanol adopts the trans form and binds with water through an O-H⋅⋅⋅Ow and an Ow -H⋅⋅⋅π hydrogen bond. Each rotational transition displays a doublet with a relative intensity ratio of 1 : 3, due to a hindered internal rotation of water around its C2 axis. This study provides the information on accurate geometry of 1-phenylethanol (PE) and large amplitude motion of water in the PE monohydrate.
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Affiliation(s)
- Yang Zheng
- Department of Chemistry, School of Chemistry and Chemical Engineering, Chongqing University, Daxuecheng South Rd. 55, 401331, Chongqing, China.,Sinopec Maoming Petrochemical Company, 525000, Maoming, Guangdong, China
| | - Junhua Chen
- School of Pharmacy, Guizhou Medical University, 550025, Guiyang, Guizhou, China
| | - Chunguo Duan
- Department of Chemistry, School of Chemistry and Chemical Engineering, Chongqing University, Daxuecheng South Rd. 55, 401331, Chongqing, China
| | - Xinyue Zhang
- Department of Chemistry, School of Chemistry and Chemical Engineering, Chongqing University, Daxuecheng South Rd. 55, 401331, Chongqing, China
| | - Xuefang Xu
- Department of Chemistry, School of Chemistry and Chemical Engineering, Chongqing University, Daxuecheng South Rd. 55, 401331, Chongqing, China
| | - Qian Gou
- Department of Chemistry, School of Chemistry and Chemical Engineering, Chongqing University, Daxuecheng South Rd. 55, 401331, Chongqing, China.,Congqing Key Laboratory of Theoretical and Computational Chemistry, Daxuecheng South Rd. 55, 401331, Chongqing, China
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Carlson CD, Hazrah AS, Mason D, Yang Q, Seifert NA, Xu Y. Alternating 1-Phenyl-2,2,2-Trifluoroethanol Conformational Landscape With the Addition of One Water: Conformations and Large Amplitude Motions. J Phys Chem A 2022; 126:7250-7260. [PMID: 36191084 DOI: 10.1021/acs.jpca.2c05803] [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 1:1 adduct of 1-phenyl-2,2,2-trifluoroethanol (PhTFE), a chiral fluoroalcohol, with water was investigated using chirped pulse Fourier transform microwave spectroscopy and computational methods. While PhTFE itself was predicted to have three minima, I (gauche+), II (trans), and III (gauche-), only I and II were stable and only I was observed experimentally. A systematic search of the PhTFE···H2O conformational landscape identified 110 stable minima, 14 of which are within a 15 kJ mol-1 energy window. Rotational spectra of the two PhTFE···H2O conformers along with several deuterium and 18O isotopologues were assigned, and the isotopic data were used to verify the corresponding structures. In the two observed monohydrate conformers, one contains PhTFE I where the water subunit is inserted into the existing intramolecular OH···F contact of I, and the binary adduct is stabilized by two intermolecular contacts: OH···OW and HW···F, whereas the other contains PhTFE II where the water subunit interacts with both the alcohol hydrogen and phenyl ring of II, demonstrating that interaction with water sufficiently stabilizes II for its observation in a jet expansion. Interestingly, the predicted electric dipole moment components at the identified minima deviate considerably from the experimental ones. Such deviations were analyzed in terms of dynamic effects associated with the large amplitude motions of the unbound HW. In addition, tunnelling effects associated with the exchange of the bonded and nonbonded HW were also discussed.
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Affiliation(s)
- Colton D Carlson
- Department of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2, Canada
| | - Arsh S Hazrah
- Department of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2, Canada
| | - Daniel Mason
- Department of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2, Canada
| | - Qian Yang
- Department of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2, Canada
| | - Nathan A Seifert
- Department of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2, Canada.,Department of Chemistry and Chemical & Biomedical Engineering, University of New Haven, 300 Boston Post Rd, West Haven, Connecticut 06516, United States
| | - Yunjie Xu
- Department of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2, Canada
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