1
|
Rouquet E, Dupont J, Lepere V, Garcia GA, Nahon L, Zehnacker A. Conformer-Selective Photoelectron Circular Dichroism. Angew Chem Int Ed Engl 2024; 63:e202401423. [PMID: 38442011 DOI: 10.1002/anie.202401423] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2024] [Revised: 03/04/2024] [Accepted: 03/05/2024] [Indexed: 03/07/2024]
Abstract
Conformational flexibility and chirality both play a key role in molecular recognition. It is therefore very useful to develop spectroscopic methods that simultaneously probe both properties. It has been theoretically predicted that photoelectron circular dichroism (PECD) should be very sensitive to conformational isomerism. However, experimental proof has been less forthcoming and only exists for a very few favorable cases. Here, we present a new PECD scheme based on resonance-enhanced two-photon ionization (RE2PI) using UV/Vis nanosecond laser excitations. The spectral resolution obtained thereby guarantees conformer-selectivity by inducing resonant conformer-specific ππ* S1←S0 transitions. We apply this experimental scheme to the study of chiral 1-indanol, which exists in two conformers linked by a ring inversion and defined by the position of the hydroxyl group, namely axial and equatorial. We show that the PECD of the equatorial and axial forms considerably differ in sign, magnitude and shape. We also discuss the influence of the total ionization energy, vibronic excitation of intermediate and final states, and relative polarization of the excitation and ionization lasers. Conformer-specificity adds a new dimension to the applications of PECD in analytical chemistry addressing now the general case of floppy systems.
Collapse
Affiliation(s)
- Etienne Rouquet
- Institut des Sciences Moléculaires d'Orsay (ISMO), CNRS, Université Paris-Saclay, F-91405, Orsay, France
- Synchrotron Soleil, L'Orme des Merisiers, St. Aubin BP48, F-91192, Gif sur Yvette, France
| | - Jennifer Dupont
- Institut des Sciences Moléculaires d'Orsay (ISMO), CNRS, Université Paris-Saclay, F-91405, Orsay, France
| | - Valeria Lepere
- Institut des Sciences Moléculaires d'Orsay (ISMO), CNRS, Université Paris-Saclay, F-91405, Orsay, France
| | - Gustavo A Garcia
- Synchrotron Soleil, L'Orme des Merisiers, St. Aubin BP48, F-91192, Gif sur Yvette, France
| | - Laurent Nahon
- Synchrotron Soleil, L'Orme des Merisiers, St. Aubin BP48, F-91192, Gif sur Yvette, France
| | - Anne Zehnacker
- Institut des Sciences Moléculaires d'Orsay (ISMO), CNRS, Université Paris-Saclay, F-91405, Orsay, France
| |
Collapse
|
2
|
Bowles J, Jähnigen S, Agostini F, Vuilleumier R, Zehnacker A, Calvo F, Clavaguéra C. Vibrational Circular Dichroism Spectroscopy with a Classical Polarizable Force Field: Alanine in the Gas and Condensed Phases. Chemphyschem 2024; 25:e202300982. [PMID: 38318765 DOI: 10.1002/cphc.202300982] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2023] [Revised: 02/05/2024] [Accepted: 02/06/2024] [Indexed: 02/07/2024]
Abstract
Polarizable force fields are an essential component for the chemically accurate modeling of complex molecular systems with a significant degree of fluxionality, beyond harmonic or perturbative approximations. In this contribution we examine the performance of such an approach for the vibrational spectroscopy of the alanine amino acid, in the gas and condensed phases, from the Fourier transform of appropriate time correlation functions generated along molecular dynamics (MD) trajectories. While the infrared (IR) spectrum only requires the electric dipole moment, the vibrational circular dichroism (VCD) spectrum further requires knowledge of the magnetic dipole moment, for which we provide relevant expressions to be used with polarizable force fields. The AMOEBA force field was employed here to model alanine in the neutral and zwitterionic isolated forms, solvated by water or nitrogen, and as a crystal. Within this framework, comparison of the electric and magnetic dipole moments to those obtained with nuclear velocity perturbation theory based on density-functional theory for the same MD trajectories are found to agree well with one another. The statistical convergence of the IR and VCD spectra is examined and found to be more demanding in the latter case. Comparisons with experimental frequencies are also provided for the condensed phases.
Collapse
Affiliation(s)
- Jessica Bowles
- Université Paris-Saclay, CNRS, Institut de Chimie Physique UMR8000, 91405, Orsay, France
| | - Sascha Jähnigen
- PASTEUR Laboratory, Département de Chimie, Ecole Normale Supérieure, PSL University, Sorbonne Université, CNRS, 75005, Paris, France
| | - Federica Agostini
- Université Paris-Saclay, CNRS, Institut de Chimie Physique UMR8000, 91405, Orsay, France
| | - Rodolphe Vuilleumier
- PASTEUR Laboratory, Département de Chimie, Ecole Normale Supérieure, PSL University, Sorbonne Université, CNRS, 75005, Paris, France
| | - Anne Zehnacker
- Université Paris-Saclay, CNRS, Institut des Sciences Moléculaires d'Orsay UMR8214, 91405, Orsay, France
| | - Florent Calvo
- Université Grenoble Alpes, CNRS, LIPhy, 38000, Grenoble, France
| | - Carine Clavaguéra
- Université Paris-Saclay, CNRS, Institut de Chimie Physique UMR8000, 91405, Orsay, France
| |
Collapse
|
3
|
Yang Y, Alshalalfeh M, Xu Y. Conformational distributions of tetrahydro-2-turoic acid in water at different pH values by their IR and vibrational circular dichroism spectra. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2024; 307:123634. [PMID: 37976578 DOI: 10.1016/j.saa.2023.123634] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2023] [Revised: 11/01/2023] [Accepted: 11/07/2023] [Indexed: 11/19/2023]
Abstract
Infrared (IR) and vibrational circular dichroism (VCD) spectra of tetrahydro-2-furoic acid (THFA) in aqueous solutions under several different pH conditions were recorded. To interpret the IR and VCD spectra of THFA obtained in highly acidic and basic aqueous solutions, extensive and systematic conformational searches were conducted to acquire the low-energy minima for both the neutral and deprotonated forms of THFA species, as well as their hydrated clusters. This was accomplished by using the conformer-rotamer ensemble sampling tool (CREST) with an implicit solvation model for water. The CREST candidates were further optimized at the B3LYP-D3BJ/def2-TZVP level of theory. The simulated VCD spectra of the neutral THFA conformers in the polarizable continuum model (PCM) of water alone exhibit little agreement with the experimental data under highly acidic conditions. Applying the clusters-in-a-liquid solvation model by considering the monohydrate THFA conformers in the PCM of water, significantly improved agreement with the experimental data. Similarly, the deprotonated THFA species solvated with one to four explicit water molecules in the PCM of water were considered. While the IR and VCD spectra of the deprotonated THFA monohydrate conformers offer the best agreement with the experimental data, other larger hydrated clusters, particularly the dihydrates, also contribute to the spectra. Through the synergistic combined experimental and theoretical approach used in the study, comprehensive conformational distributions of the predominant THFA species across various pH conditions were extracted.
Collapse
Affiliation(s)
- Yanqing Yang
- Department of Chemistry, University of Alberta, Edmonton, AB, T6G 2G2, Canada
| | - Mutasem Alshalalfeh
- Department of Chemistry, University of Alberta, Edmonton, AB, T6G 2G2, Canada
| | - Yunjie Xu
- Department of Chemistry, University of Alberta, Edmonton, AB, T6G 2G2, Canada.
| |
Collapse
|
4
|
Merten C. Modelling solute-solvent interactions in VCD spectra analysis with the micro-solvation approach. Phys Chem Chem Phys 2023; 25:29404-29414. [PMID: 37881890 DOI: 10.1039/d3cp03408a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2023]
Abstract
Vibrational circular dichroism (VCD) spectroscopy has become an important part of the (stereo-)chemists' toolbox as a reliable method for the determination of absolute configurations. Being the chiroptical version of infrared spectroscopy, it has also been recognized as being very sensitive to conformational changes and intermolecular interactions. This sensitivity originates from the fact that the VCD spectra of individual conformers are often more different than their IR spectra, so that changes in conformational distributions or band positions and intensities become more pronounced. What is an advantage for studies focussing on intermolecular interactions can, however, quickly turn into a major obstacle during AC determinations: solute-solvent interactions can have a strong influence on spectral signatures and they must be accurately treated when simulating VCD and IR spectra. In this perspective, we showcase selected examples which exhibit particularly pronounced solvent effects. It is demonstrated that it is typically sufficient to model solute-solvent interactions by placing single solvent molecules near hydrogen bonding sites of the solute and subsequently use the optimized structures for spectra simulations. This micro-solvation approach works reasonably well for medium-sized, not too conformationally flexible molecules. We thus also discuss its limitations and outline the next steps that method development needs to take in order to further improve the workflows for VCD spectra predictions.
Collapse
Affiliation(s)
- Christian Merten
- Ruhr Universität Bochum, Fakultät für Chemie und Biochemie, Organische Chemie II, Universitätsstraße 150, 44801 Bochum, Germany.
| |
Collapse
|
5
|
Hazrah AS, Insausti A, Ma J, Al-Jabiri MH, Jäger W, Xu Y. Wetting vs Droplet Aggregation: A Broadband Rotational Spectroscopic Study of 3-Methylcatechol⋅⋅⋅Water Clusters. Angew Chem Int Ed Engl 2023; 62:e202310610. [PMID: 37697450 DOI: 10.1002/anie.202310610] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Revised: 09/07/2023] [Accepted: 09/11/2023] [Indexed: 09/13/2023]
Abstract
Two competing solvation pathways of 3-methylcatechol (MC), an atmospherically relevant aromatic molecule, with up to five water molecules were explored in detail by using a combination of broadband rotational spectroscopy and computational chemistry. Theoretically, two different pathways of solvation emerge: the commonly observed droplet pathway which involves preferential binding among the water molecules while the solute serves as an anchor point for the formation of a water cluster, and an unexpected wetting pathway which involves interactions between the water molecules and the aromatic face of MC, i.e., a wetting of the π-surface. Conclusive identification of the MC hydrate structures, and therefore the wetting pathway, was facilitated by rotational spectra of the parent MC hydrates and several H2 18 O and 13 C isotopologues which exhibit splittings associated with methyl internal rotation and/or water tunneling motions. Theoretical modelling and analyses offer insights into the tunneling and conversion barriers associated with the observed hydrate conformers and the nature of the non-covalent interactions involved in choosing the unusual wetting pathway.
Collapse
Affiliation(s)
- Arsh S Hazrah
- Department of Chemistry, University of Alberta, Edmonton, AB T6G 2G2, Canada
- Current Address: Department of Molecular Spectroscopy, Max Planck Institute for Polymer Research, Ackermannweg 10, 55128, Mainz, Germany
| | - Aran Insausti
- Department of Chemistry, University of Alberta, Edmonton, AB T6G 2G2, Canada
- Departamento de Química Física, Facultad de Ciencia y Tecnología, Universidad del País Vasco (UPV-EHU), 48080, Bilbao, Spain
- Biofisika Institute (CSIC, UPV/EHU), University of the Basque Country (UPV/EHU), 48940, Leioa, Spain
| | - 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
| | - Wolfgang Jäger
- Department of Chemistry, University of Alberta, Edmonton, AB T6G 2G2, Canada
| | - Yunjie Xu
- Department of Chemistry, University of Alberta, Edmonton, AB T6G 2G2, Canada
| |
Collapse
|
6
|
Jähnigen S. Vibrational Circular Dichroism Spectroscopy of Chiral Molecular Crystals: Insights from Theory. Angew Chem Int Ed Engl 2023; 62:e202303595. [PMID: 37071543 DOI: 10.1002/anie.202303595] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Revised: 04/18/2023] [Accepted: 04/18/2023] [Indexed: 04/19/2023]
Abstract
Chirality is a curious phenomenon that appears in various forms. While the concept of molecular (RS-)chirality is ubiquitous in chemistry, there are also more intricate forms of structural chirality. One of them is the enantiomorphism of crystals, especially molecular crystals, that describes the lack of mirror symmetry in the unit cell. Its relation to molecular chirality is not obvious, but still an open question, which can be addressed with chiroptical tools. Vibrational circular dichroism (VCD) denotes chiral infrared (IR) spectroscopy that is susceptible to both, the molecular as well as the intermolecular space by means of vibrational transitions. When carried out in the solid state, VCD delivers a very rich set of non-local contributions that are determined by crystal packing and collective motion. Since its discovery in the 1970s, VCD has become the method of choice for the determination of absolute configurations, but its applicability reaches beyond towards the study of different crystal forms and polymorphism. This brief review summarises the theoretical concepts of crystal chirality and how computations of solid-state VCD can shed light into the intimate connection of chiral structure and vibrational optical activity.
Collapse
Affiliation(s)
- Sascha Jähnigen
- PASTEUR, Département de Chimie, Ecole Normale Supérieure, PSL University, Sorbonne Université, CNRS, 75005, Paris, France
| |
Collapse
|
7
|
Perera AS, Carlson CD, Cheramy J, Xu Y. Infrared and vibrational circular dichroism spectra of methyl β-D-glucopyranose in water: The application of the quantum cluster growth and clusters-in-a-liquid solvation models. Chirality 2023; 35:718-731. [PMID: 37162747 DOI: 10.1002/chir.23576] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 04/10/2023] [Accepted: 04/18/2023] [Indexed: 05/11/2023]
Abstract
The infrared (IR) and vibrational circular dichroism (VCD) spectra of methyl β-D-glucopyranose in water were measured. Both implicit and explicit solvation models were utilized to explain the observed spectra. The vast body of existing experimental and theoretical data suggested that about eight explicit water molecules are needed to account for the solvent effects, supported by the current Quantum Cluster Growth (QCG) analysis. Extensive manual and systematic conformational searches of the molecular target and its water clusters were carried out by using a recently developed conformational searching tool, conformer-rotamer ensemble sampling tool (CREST), and the microsolvation model in the associated QCG code. The Boltzmann averaged IR and VCD spectra of the methyl β-D-glucopyranose-(water)n (n = 8) conformers in the PCM of water provide better agreement with the experimental ones than those with n = 0, 1, and 2. The explicit solvation with eight water molecules was shown to greatly modify the conformational preference of methyl β-D-glucopyranose from its monomeric form. Further analyses show that the result is consistent with the existence of long-lived methyl β-D-glucopyranose monohydrates with the additional explicit water effects being accounted for with the quantum mechanical treatment of the other seven close-by water molecules in the PCM of water.
Collapse
Affiliation(s)
| | - Colton D Carlson
- Department of Chemistry, University of Alberta, Edmonton, Alberta, Canada
| | - Joseph Cheramy
- Department of Chemistry, University of Alberta, Edmonton, Alberta, Canada
| | - Yunjie Xu
- Department of Chemistry, University of Alberta, Edmonton, Alberta, Canada
| |
Collapse
|
8
|
Groß J, Kühlborn J, Pusch S, Weber C, Andernach L, Renzer G, Eckhardt P, Brauer J, Opatz T. Comparison of different density functional theory methods for the calculation of vibrational circular dichroism spectra. Chirality 2023; 35:753-765. [PMID: 37227055 DOI: 10.1002/chir.23580] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Revised: 05/02/2023] [Accepted: 05/03/2023] [Indexed: 05/26/2023]
Abstract
The determination of the absolute configuration (AC) of an organic molecule is still a challenging task for which the combination of spectroscopic with quantum-mechanical methods has become a promising approach. In this study, we investigated the accuracy of DFT methods (480 overall combinations of 15 functionals, 16 basis sets, and 2 solvation models) to calculate the VCD spectra of six chiral organic molecules in order to benchmark their capability to facilitate the determination of the AC.
Collapse
Affiliation(s)
- Jonathan Groß
- Department of Chemistry, Johannes Gutenberg University, Mainz, Germany
| | - Jonas Kühlborn
- Department of Chemistry, Johannes Gutenberg University, Mainz, Germany
| | - Stefan Pusch
- Department of Chemistry, Johannes Gutenberg University, Mainz, Germany
| | - Carina Weber
- Department of Chemistry, Johannes Gutenberg University, Mainz, Germany
| | - Lars Andernach
- Department of Chemistry, Johannes Gutenberg University, Mainz, Germany
| | - Galit Renzer
- Department of Chemistry, Johannes Gutenberg University, Mainz, Germany
| | - Paul Eckhardt
- Department of Chemistry, Johannes Gutenberg University, Mainz, Germany
| | - Jan Brauer
- Department of Chemistry, Johannes Gutenberg University, Mainz, Germany
| | - Till Opatz
- Department of Chemistry, Johannes Gutenberg University, Mainz, Germany
| |
Collapse
|
9
|
Lemler PM, Craft CL, Pollok CH, Regan TP, Vaccaro PH. Isolated and solvated chiroptical behavior in conformationally flexible butanamines. Chirality 2023; 35:586-618. [PMID: 37550220 DOI: 10.1002/chir.23570] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2023] [Revised: 04/15/2023] [Accepted: 04/17/2023] [Indexed: 08/09/2023]
Abstract
The nonresonant optical activity of two highly flexible aliphatic amines, (2R)-3-methyl-2-butanamine (R-MBA) and (2R)-(3,3)-dimethyl-2-butanamine (R-DMBA), has been probed under isolated and solvated conditions to examine the roles of conformational isomerism and to explore the influence of extrinsic perturbations. The optical rotatory dispersion (ORD) measured in six solvents presented uniformly negative rotatory powers over the 320-590 nm region, with the long-wavelength magnitude of chiroptical response growing nearly monotonically as the dielectric constant of the surroundings diminished. The intrinsic specific optical rotation,α λ T (in deg dm-1 [g/mL]-1 ), extracted for ambient vapor-phase samples of R-MBA [-11.031(98) and -2.29 (11)] and R-DMBA [-9.434 (72) and -1.350 (48)] at 355 and 633 nm were best reproduced by counterintuitive solvents of high polarity (yet low polarizability) like acetonitrile and methanol. Attempts to interpret observed spectral signatures quantitatively relied on the linear-response frameworks of density-functional theory (B3LYP, cam-B3LYP, and dispersion-corrected analogs) and coupled-cluster theory (CCSD), with variants of the polarizable continuum model (PCM) deployed to account for the effects of implicit solvation. Building on the identification of several low-lying equilibrium geometries (nine for R-MBA and three for R-DMBA), ensemble-averaged ORD profiles were calculated at T = 300 K by means of the independent-conformer ansatz, which enabled response properties predicted for the optimized structure of each isomer to be combined through Boltzmann-weighted population fractions derived from corresponding relative internal-energy or free-energy values, the latter of which stemmed from composite CBS-APNO and G4 analyses. Although reasonable accord between theory and experiment was realized for the isolated (vapor-phase) species, the solution-phase results were less satisfactory and tended to degrade progressively as the solvent polarity increased. These trends were attributed to solvent-mediated changes in structural parameters and energy metrics for the transition states that separate and putatively isolate the equilibrium conformations supported by the ground electronic potential-energy surface, with the resulting displacement of barrier locations and/or decrease of barrier heights compromising the underlying premise of the independent-conformer ansatz.
Collapse
Affiliation(s)
- Paul M Lemler
- Department of Chemistry, Yale University, New Haven, Connecticut, USA
- Intel Corporation, Hillsboro, Oregon, USA
| | - Clayton L Craft
- Department of Chemistry, Yale University, New Haven, Connecticut, USA
- United States Air Force Research Laboratory, Rome, New York, USA
| | - Corina H Pollok
- Department of Chemistry, Yale University, New Haven, Connecticut, USA
- Organische Chemie II, Ruhr-Universität Bochum, Bochum, Germany
| | - Thomas P Regan
- Department of Chemistry, Yale University, New Haven, Connecticut, USA
| | - Patrick H Vaccaro
- Department of Chemistry, Yale University, New Haven, Connecticut, USA
| |
Collapse
|
10
|
Bowles J, Jähnigen S, Vuilleumier R, Calvo F, Clavaguéra C, Agostini F. Influence of the environment on the infrared spectrum of alanine: An effective mode analysis. J Chem Phys 2023; 158:094305. [PMID: 36889973 DOI: 10.1063/5.0135608] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/10/2023] Open
Abstract
The vibrational spectrum of the alanine amino acid was computationally determined in the infrared range 1000-2000 cm-1, under various environments encompassing the gas, hydrated, and crystalline phases, by means of classical molecular dynamics trajectories, carried out with the Atomic Multipole Optimized Energetics for Biomolecular Simulation polarizable force field. An effective mode analysis was performed, in which the spectra are optimally decomposed into different absorption bands arising from well-defined internal modes. In the gas phase, this analysis allows us to unravel the significant differences between the spectra obtained for the neutral and zwitterionic forms of alanine. In condensed phases, the method provides invaluable insight into the molecular origins of the vibrational bands and further shows that peaks with similar positions can be traced to rather different molecular motions.
Collapse
Affiliation(s)
- Jessica Bowles
- Université Paris-Saclay, CNRS, Institut de Chimie Physique UMR8000, 91405 Orsay, France
| | - Sascha Jähnigen
- Institut des Sciences Moléculaires d'Orsay (ISMO), CNRS, Université Paris-Saclay, 91405 Orsay, France
| | - Rodolphe Vuilleumier
- PASTEUR Laboratory, Département de Chimie, Ecole Normale Supérieure, PSL University, Sorbonne Université, CNRS, 75005 Paris, France
| | - Florent Calvo
- Université Grenoble Alpes, CNRS, LIPhy, F-38000 Grenoble, France
| | - Carine Clavaguéra
- Université Paris-Saclay, CNRS, Institut de Chimie Physique UMR8000, 91405 Orsay, France
| | - Federica Agostini
- Université Paris-Saclay, CNRS, Institut de Chimie Physique UMR8000, 91405 Orsay, France
| |
Collapse
|
11
|
Losev TV, Gerasimov IS, Panova MV, Lisov AA, Abdyusheva YR, Rusina PV, Zaletskaya E, Stroganov OV, Medvedev MG, Novikov FN. Quantum Mechanical-Cluster Approach to Solve the Bioisosteric Replacement Problem in Drug Design. J Chem Inf Model 2023; 63:1239-1248. [PMID: 36763797 DOI: 10.1021/acs.jcim.2c01212] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
Abstract
Bioisosteres are molecules that differ in substituents but still have very similar shapes. Bioisosteric replacements are ubiquitous in modern drug design, where they are used to alter metabolism, change bioavailability, or modify activity of the lead compound. Prediction of relative affinities of bioisosteres with computational methods is a long-standing task; however, the very shape closeness makes bioisosteric substitutions almost intractable for computational methods, which use standard force fields. Here, we design a quantum mechanical (QM)-cluster approach based on the GFN2-xTB semi-empirical quantum-chemical method and apply it to a set of H → F bioisosteric replacements. The proposed methodology enables advanced prediction of biological activity change upon bioisosteric substitution of -H with -F, with the standard deviation of 0.60 kcal/mol, surpassing the ChemPLP scoring function (0.83 kcal/mol), and making QM-based ΔΔG estimation comparable to ∼0.42 kcal/mol standard deviation of in vitro experiment. The speed of the method and lack of tunable parameters makes it affordable in current drug research.
Collapse
Affiliation(s)
- Timofey V Losev
- N.D. Zelinsky Institute of Organic Chemistry of Russian Academy of Sciences, Leninsky prospect 47, 119991 Moscow, Russian Federation.,Department of Chemistry, Lomonosov Moscow State University, Leninskie Gory 1/3, 119991 Moscow, Russian Federation.,A.N. Nesmeyanov Institute of Organoelement Compounds of Russian Academy of Sciences, Vavilov Str. 28, 119991 Moscow, Russian Federation
| | - Igor S Gerasimov
- N.D. Zelinsky Institute of Organic Chemistry of Russian Academy of Sciences, Leninsky prospect 47, 119991 Moscow, Russian Federation.,Department of Chemistry, Kyungpook National University, Daegu 41566, South Korea
| | - Maria V Panova
- N.D. Zelinsky Institute of Organic Chemistry of Russian Academy of Sciences, Leninsky prospect 47, 119991 Moscow, Russian Federation
| | - Alexey A Lisov
- N.D. Zelinsky Institute of Organic Chemistry of Russian Academy of Sciences, Leninsky prospect 47, 119991 Moscow, Russian Federation
| | - Yana R Abdyusheva
- N.D. Zelinsky Institute of Organic Chemistry of Russian Academy of Sciences, Leninsky prospect 47, 119991 Moscow, Russian Federation.,National Research University Higher School of Economics, Myasnitskaya Street 20, 101000 Moscow, Russian Federation
| | - Polina V Rusina
- N.D. Zelinsky Institute of Organic Chemistry of Russian Academy of Sciences, Leninsky prospect 47, 119991 Moscow, Russian Federation
| | - Eugenia Zaletskaya
- N.D. Zelinsky Institute of Organic Chemistry of Russian Academy of Sciences, Leninsky prospect 47, 119991 Moscow, Russian Federation.,National Research University Higher School of Economics, Myasnitskaya Street 20, 101000 Moscow, Russian Federation
| | - Oleg V Stroganov
- BioMolTech Corp., 226 York Mills Rd, Toronto, Ontario M2L 1L1, Canada
| | - Michael G Medvedev
- N.D. Zelinsky Institute of Organic Chemistry of Russian Academy of Sciences, Leninsky prospect 47, 119991 Moscow, Russian Federation
| | - Fedor N Novikov
- N.D. Zelinsky Institute of Organic Chemistry of Russian Academy of Sciences, Leninsky prospect 47, 119991 Moscow, Russian Federation.,National Research University Higher School of Economics, Myasnitskaya Street 20, 101000 Moscow, Russian Federation
| |
Collapse
|
12
|
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.
Collapse
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
| |
Collapse
|
13
|
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.
Collapse
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
| |
Collapse
|
14
|
Golub TP, Feßner M, Engelage E, Merten C. Dynamic Stereochemistry of a Biphenyl‐Bisprolineamide Model Catalyst and its Imidazolidinone Intermediates. Chemistry 2022; 28:e202201317. [PMID: 35611719 PMCID: PMC9545261 DOI: 10.1002/chem.202201317] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2022] [Indexed: 12/15/2022]
Abstract
In this study, we characterize the dynamic stereochemistry of a biphenyl‐2,2’‐bis(proline amide) catalyst in chloroform and DMSO as representative weakly and strongly hydrogen bonding solvents. Using vibrational circular dichroism (VCD) spectroscopy and density functional theory (DFT) based spectra calculations, we show that the preferred axial stereochemistry of the catalyst is determined by solute‐solvent interactions. Explicitly considering solvation with DMSO molecules is found to be essential to correctly predict the conformational preferences of the catalyst. Furthermore, we investigate the stereochemistry of the corresponding enamines and imidazolidinones that are formed upon reaction with isovaleraldehyde. The enamines are found to rapidly convert to endo‐imidazolidinones and the thermodynamically favored exo‐imidazolidinones are formed only slowly. The present study demonstrates that the stereochemistry of these imidazolidinones can be deduced directly from the VCD spectra analysis without any further detailed analysis of NMR spectra. Hence, we herein exemplify the use of VCD spectroscopy for an in situ characterization of intermediates relevant in asymmetric catalysts.
Collapse
Affiliation(s)
- Tino P. Golub
- Ruhr Universität Bochum Fakultät für Chemie und Biochemie Organische Chemie II Universitätsstraße 150 44801 Bochum Germany
| | - Malte Feßner
- Ruhr Universität Bochum Fakultät für Chemie und Biochemie Organische Chemie II Universitätsstraße 150 44801 Bochum Germany
| | - Elric Engelage
- Ruhr Universität Bochum Fakultät für Chemie und Biochemie Organische Chemie II Universitätsstraße 150 44801 Bochum Germany
| | - Christian Merten
- Ruhr Universität Bochum Fakultät für Chemie und Biochemie Organische Chemie II Universitätsstraße 150 44801 Bochum Germany
| |
Collapse
|
15
|
Eikås KDR, Beerepoot MTP, Ruud K. A Computational Protocol for Vibrational Circular Dichroism Spectra of Cyclic Oligopeptides. J Phys Chem A 2022; 126:5458-5471. [PMID: 35930395 PMCID: PMC9393892 DOI: 10.1021/acs.jpca.2c02953] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Cyclic peptides are a promising class of compounds for next-generation antibiotics as they may provide new ways of limiting antibiotic resistance development. Although their cyclic structure will introduce some rigidity, their conformational space is large and they usually have multiple chiral centers that give rise to a wide range of possible stereoisomers. Chiroptical spectroscopies such as vibrational circular dichroism (VCD) are used to assign stereochemistry and discriminate enantiomers of chiral molecules, often in combination with electronic structure methods. The reliable determination of the absolute configuration of cyclic peptides will require robust computational methods than can identify all significant conformers and their relative population and reliably assign their stereochemistry from their chiroptical spectra by comparison with ab initio calculated spectra. We here present a computational protocol for the accurate calculation of the VCD spectra of a series of flexible cyclic oligopeptides. The protocol builds on the Conformer-Rotamer Ensemble Sampling Tool (CREST) developed by Grimme and co-workers ( Phys. Chem. Chem. Phys. 2020, 22, 7169-7192 and J. Chem. Theory. Comput. 2019, 15, 2847-2862) in combination with postoptimizations using B3LYP and moderately sized basis sets. Our recommended computational protocol for the computation of VCD spectra of cyclic oligopeptides consists of three steps: (1) conformational sampling with CREST and tight-binding density functional theory (xTB); (2) energy ranking based on single-point energy calculations as well as geometry optimization and VCD calculations of conformers that are within 2.5 kcal/mol of the most stable conformer using B3LYP/6-31+G*/CPCM; and (3) VCD spectra generation based on Boltzmann weighting with Gibbs free energies. Our protocol provides a feasible basis for generating VCD spectra also for larger cyclic peptides of biological/pharmaceutical interest and can thus be used to investigate promising compounds for next-generation antibiotics.
Collapse
Affiliation(s)
- Karolina Di Remigio Eikås
- Hylleraas Centre for Quantum Molecular Sciences, Department of Chemistry, UiT The Arctic University of Norway, 9037 Tromsø, Norway
| | - Maarten T P Beerepoot
- Hylleraas Centre for Quantum Molecular Sciences, Department of Chemistry, UiT The Arctic University of Norway, 9037 Tromsø, Norway
| | - Kenneth Ruud
- Hylleraas Centre for Quantum Molecular Sciences, Department of Chemistry, UiT The Arctic University of Norway, 9037 Tromsø, Norway.,Norwegian Defence Research Establishment, P.O. Box 25, 2027 Kjeller, Norway
| |
Collapse
|
16
|
Dupont J, Guillot R, Lepère V, Zehnacker A. Jet-cooled laser spectroscopy and solid-state vibrational circular dichroism of the cyclo-(Tyr-Phe) diketopiperazine dipeptide. J Mol Struct 2022. [DOI: 10.1016/j.molstruc.2022.133059] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
|
17
|
Weirich L, Tusha G, Engelage E, Schäfer LV, Merten C. VCD spectroscopy reveals conformational changes of chiral crown ethers upon complexation of potassium and ammonium cations. Phys Chem Chem Phys 2022; 24:11721-11728. [PMID: 35506489 DOI: 10.1039/d2cp01309f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Two chiral derivatives of 18-crown-6, namely the host molecules 2,3-diphenyl- and 2-phenyl-18c6, serve as model systems to investigate whether VCD spectroscopy can be used to monitor conformational changes occurring upon complexation of guests. Host-guest complexes of both crown ethers were prepared by addition of KNO3. The more bulky 2,3-diphenyl-18c6 is found to undergo major conformational changes upon encapsulation of K+, which are revealed as characteristic changes of the VCD spectral signatures. In contrast, while 2-phenyl-18c6 also incorporates K+ into the macrocycle, strong conformational changes are not occurring and thus spectral changes are negligible. With an octyl ammonium cation as guest molecule, 2,3-diphenyl-18c6 shows the same conformational and spectral changes that were observed for K+-complexes. In addition, the asymmetric NH3-deformation modes are found to gain VCD intensity through an induced VCD process. An analysis of the vibrational spectra enables a differentiation of VCD active and inactive guest modes: There appears to be a correlation between the symmetry of the vibrational mode and the induced VCD intensity. While this finding makes the host-guest complexes interesting systems for future theoretical studies on the origin of induced VCD signatures, the observations described in this study demonstrate that VCD spectroscopy is indeed a suitable technique for the characterization of supramolecular host-guest complexes.
Collapse
Affiliation(s)
- Luisa Weirich
- Ruhr-Universität Bochum, Fakultät für Chemie und Biochemie, Organische Chemie II, Universitätsstraße 150, 44801 Bochum, Germany.
| | - Gers Tusha
- Ruhr-Universität Bochum, Fakultät für Chemie und Biochemie, Theoretische Chemie, Universitätsstraße 150, 44801 Bochum, Germany
| | - Elric Engelage
- Ruhr-Universität Bochum, Fakultät für Chemie und Biochemie, Organische Chemie II, Universitätsstraße 150, 44801 Bochum, Germany.
| | - Lars V Schäfer
- Ruhr-Universität Bochum, Fakultät für Chemie und Biochemie, Theoretische Chemie, Universitätsstraße 150, 44801 Bochum, Germany
| | - Christian Merten
- Ruhr-Universität Bochum, Fakultät für Chemie und Biochemie, Organische Chemie II, Universitätsstraße 150, 44801 Bochum, Germany.
| |
Collapse
|
18
|
Yang Y, Cheramy J, Brehm M, Xu Y. Raman Optical Activity of N-Acetyl-L-Cysteine in water and in methanol: the "clusters-in-a-liquid" model and ab initio molecular dynamics simulations. Chemphyschem 2022; 23:e202200161. [PMID: 35353934 DOI: 10.1002/cphc.202200161] [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: 03/09/2022] [Revised: 03/29/2022] [Indexed: 11/06/2022]
Abstract
Raman and Raman Optical Activity (ROA) spectra of N-acetyl-L-cysteine (NALC), a flexible chiral molecule, were measured in water and in methanol to evaluate the solvent effects. Two different solvation approaches, i.e. the DFT based clusters-in-a-liquid solvent model and the ab initio molecular dynamics (AIMD) simulations, were applied to simulate the Raman and ROA spectra. Systematic conformational searches were carried out using a recently developed conformational searching tool, CREST, with the inclusion of polarizable continuum model of water and of methanol. The CREST candidates of NALC and the NALC-solvent complexes were re-optimized and their Raman and ROA simulations were done at the B3LYP-D3BJ/def2-TZVP and the B3LYP-aug-cc-pVDZ//cc-pVTZ levels. Also, AIMD simulations , which includes some anharmonic effects and all intermolecular interactions in solution, were performed. By empirically weighting the computed Raman and ROA spectra of each conformer, good agreements with the experimental data were achieved with both approaches, while AIMD offered some improvements in the carbonyl and in the low wavenumber regions over the static DFT approach. The pros and cons of these two different approaches for accounting the solvent effects on Raman and ROA of this flexible chiral system will also be discussed.
Collapse
Affiliation(s)
| | | | - Martin Brehm
- Martin-Luther-Universität Halle-Wittenberg: Martin-Luther-Universitat Halle-Wittenberg, Chemistry, GERMANY
| | - Yunjie Xu
- University of Alberta Faculty of Science, Chemistry Department, 11227 Saskatchewan Drive, T6G 2G2, Edmonton, CANADA
| |
Collapse
|
19
|
Dupont J, Lepère V, Zehnacker A, Hartweg S, Garcia GA, Nahon L. Photoelectron Circular Dichroism as a Signature of Subtle Conformational Changes: The Case of Ring Inversion in 1-Indanol. J Phys Chem Lett 2022; 13:2313-2320. [PMID: 35245057 DOI: 10.1021/acs.jpclett.2c00074] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Chirality plays a fundamental role in the molecular recognition processes. Molecular flexibility is also crucial in molecular recognition, allowing the interacting molecules to adjust their structures and hence optimize the interaction. Methods probing simultaneously chirality and molecular conformation are therefore crucially needed. Taking advantage of a possible control in the gas phase of the conformational distribution between the equatorial and axial conformers resulting from a ring inversion in jet-cooled 1-indanol, we demonstrate here the sensitivity of valence-shell photoelectron circular dichroism (PECD) to both chirality and subtle conformational changes, in a case where the photoelectron spectra of the two conformers are identical. For the highest occupied orbital, we observe a dramatic inversion of the PECD-induced photoelectron asymmetries, while the photoionization cross-section and usual anisotropy (β) parameter are completely insensitive to conformational isomerism. Such a sensitivity is a major asset for the ongoing developments of PECD-based techniques as a sensitive chiral (bio)chemical analytical tool in the gas phase.
Collapse
Affiliation(s)
- Jennifer Dupont
- Institut des Sciences Moléculaires d'Orsay (ISMO), CNRS, Université Paris-Saclay, F-91405 Orsay, France
| | - Valéria Lepère
- Institut des Sciences Moléculaires d'Orsay (ISMO), CNRS, Université Paris-Saclay, F-91405 Orsay, France
| | - Anne Zehnacker
- Institut des Sciences Moléculaires d'Orsay (ISMO), CNRS, Université Paris-Saclay, F-91405 Orsay, France
| | - Sebastian Hartweg
- Synchrotron Soleil, L'Orme des Merisiers, St. Aubin BP48, F-91192 Gif sur Yvette, France
| | - Gustavo A Garcia
- Synchrotron Soleil, L'Orme des Merisiers, St. Aubin BP48, F-91192 Gif sur Yvette, France
| | - Laurent Nahon
- Synchrotron Soleil, L'Orme des Merisiers, St. Aubin BP48, F-91192 Gif sur Yvette, France
| |
Collapse
|
20
|
Rode JE, Lyczko K, Kosińska K, Matalińska J, Dyniewicz J, Misicka A, Dobrowolski JC, Lipiński PFJ. The solid state VCD of a novel N-acylhydrazone trifluoroacetate. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2022; 269:120761. [PMID: 34954483 DOI: 10.1016/j.saa.2021.120761] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2021] [Revised: 11/23/2021] [Accepted: 12/12/2021] [Indexed: 06/14/2023]
Abstract
A novel N-acylhydrazone with pharmaceutical importance was subject of structural and IR/VCD investigations in the solid state. In the crystal structure, dimers of anion-cation pairs are stabilized by H-bonding and ionic interactions. Some less common interaction types, like C=N···C-NH3+ (σ-hole) interactions, hydrazone-aromatic interactions and dispersive contacts of the CF3 groups are also present in the crystal. Satisfactory reproduction of the solid state IR and VCD spectra required that quantum-chemical calculations be done on a tetramer (four cation-anion pairs) cut out from the crystal structure, exhibiting key intermolecular interactions. Ten DFT functionals were assessed as to the agreement between the calculated and experimental spectra. Various approaches to scaling of the calculated frequencies were applied. The best results were yielded with individual (optimized) frequency scaling factors (FSFs) and band half-widths at half maximum-(HWHM) for four separate spectral subregions. The best matching between the experimental and theoretical spectra (according to SimIR, SimVCD and SimVDF indices) was found for the B3PW91 functional, however, a few other functionals follow closely in the ranking. Based on the quantum chemical calculations, spectral assignments have been made.
Collapse
Affiliation(s)
- Joanna E Rode
- Institute of Nuclear Chemistry and Technology, 16 Dorodna Street, PL 03-195 Warsaw, Poland
| | - Krzysztof Lyczko
- Institute of Nuclear Chemistry and Technology, 16 Dorodna Street, PL 03-195 Warsaw, Poland
| | - Katarzyna Kosińska
- Department of Neuropeptides, Mossakowski Medical Research Institute Polish Academy of Sciences, 5 Pawińskiego Street, PL 02-106 Warsaw, Poland
| | - Joanna Matalińska
- Department of Neuropeptides, Mossakowski Medical Research Institute Polish Academy of Sciences, 5 Pawińskiego Street, PL 02-106 Warsaw, Poland
| | - Jolanta Dyniewicz
- Department of Neuropeptides, Mossakowski Medical Research Institute Polish Academy of Sciences, 5 Pawińskiego Street, PL 02-106 Warsaw, Poland
| | - Aleksandra Misicka
- Department of Neuropeptides, Mossakowski Medical Research Institute Polish Academy of Sciences, 5 Pawińskiego Street, PL 02-106 Warsaw, Poland
| | - Jan Cz Dobrowolski
- Department for Medicines Biotechnology and Bioinformatics, National Medicines Institute, 30/34 Chełmska Street, PL 00-725 Warsaw, Poland
| | - Piotr F J Lipiński
- Department of Neuropeptides, Mossakowski Medical Research Institute Polish Academy of Sciences, 5 Pawińskiego Street, PL 02-106 Warsaw, Poland.
| |
Collapse
|
21
|
Kirchner B, Blasius J, Alizadeh V, Gansäuer A, Hollóczki O. Chemistry Dissolved in Ionic Liquids. A Theoretical Perspective. J Phys Chem B 2022; 126:766-777. [PMID: 35034453 DOI: 10.1021/acs.jpcb.1c09092] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The theoretical treatment of ionic liquids must focus now on more realistic models while at the same time keeping an accurate methodology when following recent ionic liquids research trends or allowing predictability to come to the foreground. In this Perspective, we summarize in three cases of advanced ionic liquid research what methodological progress has been made and point out difficulties that need to be overcome. As particular examples to discuss we choose reactions, chirality, and radicals in ionic liquids. All these topics have in common that an explicit or accurate treatment of the electronic structure and/or intermolecular interactions is required (accurate methodology), while at the same time system size and complexity as well as simulation time (realistic model) play an important role and must be covered as well.
Collapse
Affiliation(s)
- Barbara Kirchner
- Mulliken Center for Theoretical Chemistry, University of Bonn, Beringstraße 4+6, D-53115 Bonn, Germany
| | - Jan Blasius
- Mulliken Center for Theoretical Chemistry, University of Bonn, Beringstraße 4+6, D-53115 Bonn, Germany
| | - Vahideh Alizadeh
- Mulliken Center for Theoretical Chemistry, University of Bonn, Beringstraße 4+6, D-53115 Bonn, Germany
| | - Andreas Gansäuer
- Kekulé-Institut für Organische Chemie und Biochemie, University of Bonn, Gerhard-Domagk-Straße 1, D-53121 Bonn, Germany
| | - Oldamur Hollóczki
- Mulliken Center for Theoretical Chemistry, University of Bonn, Beringstraße 4+6, D-53115 Bonn, Germany.,Department of Physical Chemistry, Faculty of Science and Technology, University of Debrecen, Egyetem tér 1, H-4010 Debrecen, Hungary
| |
Collapse
|
22
|
Golub T, Kano T, Maruoka K, Merten C. VCD spectroscopy distinguishes the enamine and iminium ion of a 1,1’-binaphthyl azepine. Chem Commun (Camb) 2022; 58:8412-8415. [DOI: 10.1039/d2cc02863h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We present a VCD spectroscopic characterization of a chiral 1,1’-binaphthyl azepine catalyst and show that the VCD spectra of an in-situ generated enamine and an ex-situ prepared iminium ion are...
Collapse
|
23
|
Le Barbu-Debus K, Zehnacker A. Competition between inter and intramolecular hydrogen bond evidenced by vibrational circular dichroism spectroscopy: The case of (1S,2R)-(-)-cis-1-amino-2-indanol. Chirality 2021; 33:858-874. [PMID: 34570370 DOI: 10.1002/chir.23362] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Revised: 08/29/2021] [Accepted: 08/31/2021] [Indexed: 02/06/2023]
Abstract
The infrared (IR) absorption and vibrational circular dichroism (VCD) spectra of an intramolecularly hydrogen-bonded chiral amino-alcohol, (1S,2R)-(-)-cis-1-amino-2-indanol, are studied in DMSO-d6 . The spectra are simulated at the density functional theory (DFT) level within the frame of the cluster-in-the-liquid model. Both IR and VCD spectra show a clear signature of the formation of intermolecular hydrogen bonds at the detriment of the intramolecular OH … N interaction present in the isolated molecule. Two solvent molecules are necessary to reproduce the experimental spectra. Whereas the first DMSO molecule captures the main spectral modifications due to hydrogen bond formation between the solute and the solvent, the second DMSO molecule is necessary for a good description of the Boltzmann contribution of the different complexes, based on their Gibbs free energy.
Collapse
Affiliation(s)
- Katia Le Barbu-Debus
- Institut des Sciences Moléculaires d'Orsay, Université Paris-Saclay, Orsay, France
| | - Anne Zehnacker
- Institut des Sciences Moléculaires d'Orsay, Université Paris-Saclay, Orsay, France
| |
Collapse
|
24
|
Jähnigen S, Sebastiani D, Vuilleumier R. The important role of non-covalent interactions for the vibrational circular dichroism of lactic acid in aqueous solution. Phys Chem Chem Phys 2021; 23:17232-17241. [PMID: 34369531 DOI: 10.1039/d1cp03106f] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
We present a computational study of vibrational circular dichroism (VCD) in solutions of (S)-lactic acid, relying on ab initio molecular dynamics (AIMD) and full solvation with bulk water. We discuss the effect of the hydrogen bond network on the aggregation behaviour of the acid: while aggregates of the solute represent conditions encountered in a weakly interacting solvent, the presence of water drastically interferes with the clusters - more strongly than originally anticipated. For both scenarios we computed the VCD spectra by means of nuclear velocity perturbation theory (NVPT). The comparison with experimental data allows us to establish a VCD-structure relationship that includes the solvent network around the chiral solute. We suggest that fundamental modes with strong polarisation such as the carbonyl stretching vibration can borrow VCD from the chirally restructured solvent cage, which extends the common explanatory models of VCD generation in aqueous solution.
Collapse
Affiliation(s)
- Sascha Jähnigen
- PASTEUR, Département de chimie, École normale supérieure, PSL University, Sorbonne Université, CNRS, 75005, Paris, France.
| | | | | |
Collapse
|
25
|
Jähnigen S, Zehnacker A, Vuilleumier R. Computation of Solid-State Vibrational Circular Dichroism in the Periodic Gauge. J Phys Chem Lett 2021; 12:7213-7220. [PMID: 34310135 DOI: 10.1021/acs.jpclett.1c01682] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
We introduce a new theoretical formalism to compute solid-state vibrational circular dichroism (VCD) spectra from molecular dynamics simulations. Having solved the origin-dependence problem of the periodic magnetic gauge, we present IR and VCD spectra of (1S,2S)-trans-1,2-cyclohexanediol obtained from first-principles molecular dynamics calculations and nuclear velocity perturbation theory, along with the experimental results. Because the structure model imposes periodic boundary conditions, the common origin of the rotational strength has hitherto been ill-defined and was approximated by means of averaging multiple origins. The new formalism reconnects the periodic model with the finite physical system and restores gauge freedom. It nevertheless fully accounts for nonlocal spatial couplings from the gauge transport term. We show that even for small simulation cells the rich nature of solid-state VCD spectra found in experiments can be reproduced to a very satisfactory level.
Collapse
Affiliation(s)
- Sascha Jähnigen
- Institut des Sciences Moléculaires d'Orsay (ISMO), CNRS, Université Paris-Saclay, 91405 Orsay, France
- PASTEUR Laboratory, Département de Chimie, Ecole Normale Supérieure, PSL University, Sorbonne Université, CNRS,, 75005 Paris, France
| | - Anne Zehnacker
- Institut des Sciences Moléculaires d'Orsay (ISMO), CNRS, Université Paris-Saclay, 91405 Orsay, France
| | - Rodolphe Vuilleumier
- PASTEUR Laboratory, Département de Chimie, Ecole Normale Supérieure, PSL University, Sorbonne Université, CNRS,, 75005 Paris, France
| |
Collapse
|
26
|
Yang Y, Cheramy J, Xu Y. Matrix Isolation-Vibrational Circular Dichroism Spectroscopic Study of Conformations and Non-Covalent Interactions of Tetrahydro-2-Furoic Acid. Chemphyschem 2021; 22:1336-1343. [PMID: 33945674 DOI: 10.1002/cphc.202100256] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Revised: 05/01/2021] [Indexed: 11/10/2022]
Abstract
The conformational landscape and aggregation behaviour of tetrahydro-2-furoic acid (THFA) were investigated by using matrix isolation-vibrational circular dichroism (MI-VCD). The well-resolved experimental MI-IR and MI-VCD features in an argon matrix at 10 K allow one to identify two dominant monomeric conformations as trans-THFA where the hydroxyl and carbonyl groups of COOH are at opposite sides, as well as one cis-conformer. At 24 K and 30 K deposition temperatures, the experimental IR and VCD spectral features reveal further growth of the binary THFA aggregates. Systematic conformational searches identified three vastly different binary binding topologies, resulting in a few hundred stable (THFA)2 conformers. Interestingly, the main binary structures observed correspond to an unusual type of structure which is made of two trans-THFA subunits, in contrast to the usual double H-bonded ring binary structures, identified in a previous solution study. The present work showcases the power of MI-VCD spectroscopy in revealing unusual structures formed in a cold rare gas matrix.
Collapse
Affiliation(s)
- Yanqing Yang
- Chemistry Department, University of Alberta Edmonton, Alberta, Canada, T6G 2G2
| | - Joseph Cheramy
- Chemistry Department, University of Alberta Edmonton, Alberta, Canada, T6G 2G2
| | - Yunjie Xu
- Chemistry Department, University of Alberta Edmonton, Alberta, Canada, T6G 2G2
| |
Collapse
|
27
|
Demarque DP, Kemper M, Merten C. VCD spectroscopy reveals that a water molecule determines the conformation of azithromycin in solution. Chem Commun (Camb) 2021; 57:4031-4034. [PMID: 33885696 DOI: 10.1039/d1cc00932j] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We report the IR and VCD spectra of azithromycin, a macrolide antibiotic with a total of 18 stereogenic centers. The computational analysis of the spectra reveals that a single water molecule has to be considered in the conformational search. Its key role is the stabilization of an extended hydrogen bonding network and an otherwise unstable conformation that determines the VCD spectral signatures.
Collapse
Affiliation(s)
- Daniel P Demarque
- Ruhr-Universität Bochum, Organische Chemie 2, Stereochemistry and Chiroptical Spectroscopy, Universitätsstraße 150, 44801 Bochum, Germany.
| | - Michael Kemper
- Ruhr-Universität Bochum, Organische Chemie 2, Stereochemistry and Chiroptical Spectroscopy, Universitätsstraße 150, 44801 Bochum, Germany.
| | - Christian Merten
- Ruhr-Universität Bochum, Organische Chemie 2, Stereochemistry and Chiroptical Spectroscopy, Universitätsstraße 150, 44801 Bochum, Germany.
| |
Collapse
|
28
|
Kirchner B, Blasius J, Esser L, Reckien W. Predicting Vibrational Spectroscopy for Flexible Molecules and Molecules with Non‐Idle Environments. ADVANCED THEORY AND SIMULATIONS 2020. [DOI: 10.1002/adts.202000223] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Barbara Kirchner
- Mulliken Center for Theoretical Chemistry Rheinische Friedrich‐Wilhelms‐Universität Bonn Beringstr. 4+6 D‐53115 Bonn Germany
| | - Jan Blasius
- Mulliken Center for Theoretical Chemistry Rheinische Friedrich‐Wilhelms‐Universität Bonn Beringstr. 4+6 D‐53115 Bonn Germany
| | - Lars Esser
- Mulliken Center for Theoretical Chemistry Rheinische Friedrich‐Wilhelms‐Universität Bonn Beringstr. 4+6 D‐53115 Bonn Germany
| | - Werner Reckien
- Mulliken Center for Theoretical Chemistry Rheinische Friedrich‐Wilhelms‐Universität Bonn Beringstr. 4+6 D‐53115 Bonn Germany
| |
Collapse
|