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Agieienko V, Buchner R. What is behind a gas stream scrubbing liquid? Monoethanolamine/water mixtures as seen by dielectric relaxation spectroscopy. Phys Chem Chem Phys 2024; 26:2312-2323. [PMID: 38165687 DOI: 10.1039/d3cp05027k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2024]
Abstract
High-quality dielectric data for monoethanolamine (MEA)/water mixtures covering the entire miscibility range are presented. For MEA concentrations c1 ≥ 1 M the obtained complex permittivity spectra, covering the frequency range from 0.05 to 89 GHz, are best described by a sum of four Debye relaxations. Modes at ∼3 GHz and ∼10 GHz are solute-specific. Whilst the first can be assigned to MEA aggregates, the second is a composite arising from "free" MEA dipoles with dynamically retarded water hydrating them. The relaxations at ∼18 GHz and ∼200 GHz essentially reflect the cooperative H-bond fluctuations of more-or-less unperturbed "bulk" water, albeit with minor solute contributions. Evaluation of the bulk-water amplitude reveals that in water-rich mixtures (c1 ≤ 3.5 M) Zt = 3.5 ± 0.2 H2O molecules hydrate a MEA molecule. Then Zt drops linearly, reaching zero for neat MEA. Supported by the literature, this concentration dependence suggests that only H2O molecules H-bonded to the NH2 and OH groups of MEA contribute to Zt. At concentrations beyond hydration shell overlap (c1 ≥ 3.5 M) these H-bonds are gradually eliminated, while new interactions with neighboring MEA molecules are formed. From the evaluation of the MEA-specific amplitudes we conclude that for c1 ≥ 2 M, including neat MEA, ∼35% of the solute molecules are in aggregates, where breaking the intermolecular NH⋯O hydrogen bond determines the dynamics.
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Affiliation(s)
- Vira Agieienko
- Laboratory of Engineering Chemistry, Research Institute for Chemistry, Lobachevsky State University of Nizhny Novgorod, 23 Gagarina av., 603022 Nizhny Novgorod, Russian Federation.
- Nanotechnology and Biotechnology Department, Nizhny Novgorod State Technical University n.a. R.E. Alekseev, 24 Minina str., 603950 Nizhny Novgorod, Russian Federation
| | - Richard Buchner
- Institut für Physikalische und Theoretische Chemie, Universität Regensburg, Universitätsstraße 31, D-93040 Regensburg, Germany
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Hydration of the Neurotransmitter γ-Aminobutyric Acid and its Isomer α-Aminobutyric Acid. J Mol Liq 2023. [DOI: 10.1016/j.molliq.2023.121363] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
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Agieienko V, Neklyudov V, Buchner R. Typical at glance but interesting when analyzed in detail: A story of Tris hydration. J Chem Phys 2022; 157:224204. [PMID: 36546815 DOI: 10.1063/5.0128391] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
This paper provides results of dielectric relaxation (DR) spectroscopy of aqueous solutions of tris(hydroxymethyl)aminomethane (Tris) covering frequencies of 0.05 ≤ ν/GHz ≤89. The DR spectra can be well fit by a sum of Cole-Cole relaxation, assigned to the solute, and 2 Debye modes already observed for neat water. Analysis of the amplitudes reveals that Tris is hydrated by 7 H2Os up to its solubility limit. However, the rather high effective solute dipole moment of ≈12 D suggests that H2O dipoles in contact with Tris should reorient independently from it. Accordingly, an alternative description of the DR spectra with a superposition of 4 Debyerelaxations was attempted. In this model, the slowest mode at ∼4 GHz arises from solute reorientation and that at ∼8 GHz was assigned to dynamically retarded hydration water, whereas relaxations at ∼18 and ∼500 GHz are again those of (rather unperturbed) bulk water. Analysis of the solvent-related modes shows that Tris indeed slows down 7-8 H2O molecules. However, the solute-solvent interaction strength is rather weak, excluding the rotation of an alleged Tris-(7-8) H2O cluster as an entity. The now derived effective dipole moment of (6.3 ± 0.5) D for the bare Tris molecule allows speculations on its conformation. With the help of computational methods, we suggest that Tris dissolved in water most likely possesses an intramolecular H-bond between the nitrogen and hydrogen atoms of amino and hydroxyl groups, respectively. In addition, computational results indicate that the seven hydration H2Os found by DR bind directly to the Tris OH groups.
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Affiliation(s)
- V Agieienko
- Laboratory of Membrane and Catalytic Processes, Nanotechnology and Biotechnology Department, Nizhny Novgorod State Technical University n.a. R.E. Alekseev, 24 Minina Str., 603950 Nizhny Novgorod, Russian Federation
| | - V Neklyudov
- Wolfson Department of Chemical Engineering, Technion-IIT, Haifa 32000, Israel
| | - R Buchner
- Institut für Physikalische und Theoretische Chemie, Universität Regensburg, Universitätsstraße 31, D-93040 Regensburg, Germany
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MAREKHA B, Hunger J. A single methyl group drastically changes urea's hydration dynamics. J Chem Phys 2022; 156:164504. [DOI: 10.1063/5.0085461] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The amphiphilicity and denaturation efficiency of urea can be tuned via alkylation. Although the interaction of alkylureas with water and proteins has been studied in detail, the hydration of 1-methylurea has remained elusive, precluding the isolation of the effect of an individual methyl group. Here, we study water dynamics in the hydration shell of 1-methylurea (1-MU) using infrared absorption and ultrafast infrared spectroscopies. We find that 1-MU hardly affects the hydrogen-bond distribution of water as probed by the OD stretching vibration of HOD molecules. Polarization resolved infrared pump-probe experiments reveal that 1-MU slows down the rotational dynamics of up to 3 water molecules in its hydration shell. Comparison to earlier results for other alkylureas suggests that further alkylation does not necessarily slow down the rotational dynamics of additional water molecules. Two-dimensional infrared experiments show that 1-MU markedly slows down the hydrogen-bond fluctuation dynamics of water, yet similar to what has been found for urea and dimethylureas. Remarkably, (alkyl-) ureas that share a similar effect on water's hydrogen-bond fluctuation dynamics share a similar (modest) protein denaturation tendency. As such, not only the hydrophobicity but also hydration of hydrophilic fragments of alkylureas may be relevant to explain their function towards biomolecules.
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Affiliation(s)
- Bogdan MAREKHA
- Max-Planck-Institute for Medical Research Department of Biomolecular Mechanisms, Germany
| | - Johannes Hunger
- Molecular Spectroscopy, Max Planck Institute for Polymer Research, Germany
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Dinda S, Sil A, Das A, Tarif E, Biswas R. Does urea modify microheterogeneous nature of ionic amide deep eutectics? Clues from non-reactive and reactive solute-centered dynamics. J Mol Liq 2022. [DOI: 10.1016/j.molliq.2021.118126] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Friesen S, Fedotova MV, Kruchinin SE, Bešter-Rogač M, Podlipnik Č, Buchner R. Hydration and counterion binding of aqueous acetylcholine chloride and carbamoylcholine chloride. Phys Chem Chem Phys 2021; 23:25086-25096. [PMID: 34747952 DOI: 10.1039/d1cp03543f] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The hydration and Cl- ion binding of the neurot†ransmitter acetylcholine (ACh+) and its synthetic analogue, carbamoylcholine (CCh+), were studied by combining dilute-solution conductivity measurements with dielectric relaxation spectroscopy and statistical mechanics calculations at 1D-RISM and 3D-RISM level. Chloride ion binding was found to be weak but not negligible. From the ∼30 water molecules coordinating ACh and CCh+ only ∼1/3 is affected in its rotational dynamics by the cation, with the majority - situated close to the hydrophobic moieties - only retarded by a factor of ∼2.5. At vanishing solute concentration cations and the ∼3-4 H2O molecules hydrogen bonding to the CO group of the solute exhibit similar rotational dynamics but increasing concentration and temperature markedly dehydrates ACh+ and CCh+.
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Affiliation(s)
- Sergej Friesen
- Institut für Physikalische und Theoretische Chemie, Universität Regensburg, 93040 Regensburg, Germany.
| | - Marina V Fedotova
- G. A. Krestov Institute of Solution Chemistry, Russian Academy of Sciences, Kademicheskaya st. 1, 153045 Ivanovo, Russian Federation.
| | - Sergey E Kruchinin
- G. A. Krestov Institute of Solution Chemistry, Russian Academy of Sciences, Kademicheskaya st. 1, 153045 Ivanovo, Russian Federation.
| | - Marija Bešter-Rogač
- Faculty of Chemistry and Chemical Technology, University of Ljubljana, Večna pot 113, SI-1000 Ljubljana, Slovenia.
| | - Črtomir Podlipnik
- Faculty of Chemistry and Chemical Technology, University of Ljubljana, Večna pot 113, SI-1000 Ljubljana, Slovenia.
| | - Richard Buchner
- Institut für Physikalische und Theoretische Chemie, Universität Regensburg, 93040 Regensburg, Germany.
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Hydration and aggregation in aqueous xylitol solutions in the wide temperature range. J Mol Liq 2021. [DOI: 10.1016/j.molliq.2021.116838] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Friesen S, Fedotova MV, Kruchinin SE, Buchner R. Hydration and dynamics of L-glutamate ion in aqueous solution. Phys Chem Chem Phys 2021; 23:1590-1600. [PMID: 33409510 DOI: 10.1039/d0cp05489e] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Aqueous solutions of sodium l-glutamate (NaGlu) in the concentration range 0 < c/M ≤ 1.90 at 25 °C were investigated by dielectric relaxation spectroscopy (DRS) and statistical mechanics (1D-RISM and 3D-RISM calculations) to study the hydration and dynamics of the l-glutamate (Glu-) anion. Although at c → 0 water molecules beyond the first hydration shell are dynamically affected, Glu- hydration is rather fragile and for c ⪆ 0.3 M apparently restricted to H2O molecules hydrogen bonding to the carboxylate groups. These hydrating dipoles are roughly parallel to the anion moment, leading to a significantly enhanced effective dipole moment of Glu-. However, l-glutamate dynamics is determined by the rotational diffusion of individual anions under hydrodynamic slip boundary conditions. Thus, the lifetime of the hydrate complexes, as well as of possibly formed [Na+Glu-]0 ionpairs and l-glutamate aggregates, cannot exceed the characteristic timescale for Glu- rotation.
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Affiliation(s)
- Sergej Friesen
- Institut für Physikalische und Theoretische Chemie, Universität Regensburg, 93040 Regensburg, Germany.
| | - Marina V Fedotova
- G. A. Krestov Institute of Solution Chemistry, Russian Academy of Sciences, Akademicheskaya St. 1, 153045 Ivanovo, Russian Federation.
| | - Sergey E Kruchinin
- G. A. Krestov Institute of Solution Chemistry, Russian Academy of Sciences, Akademicheskaya St. 1, 153045 Ivanovo, Russian Federation.
| | - Richard Buchner
- Institut für Physikalische und Theoretische Chemie, Universität Regensburg, 93040 Regensburg, Germany.
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Agieienko V, Buchner R. Dielectric relaxation of deep eutectic solvent + water mixtures: structural implications and application to microwave heating. Phys Chem Chem Phys 2020; 22:20466-20476. [DOI: 10.1039/d0cp03334k] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
All dipolar species at their full individual strengths but synchronized in motion: structural implications of cooperative dynamics in glyceline/water and reline/water mixtures.
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Affiliation(s)
- Vira Agieienko
- Department of Physical Chemistry
- A. M. Butlerov Chemical Institute
- Kazan (Volga Region) Federal University
- 420008 Kazan
- Russian Federation
| | - Richard Buchner
- Institut für Physikalische und Theoretische Chemie
- Universität Regensburg
- D-93040 Regensburg
- Germany
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Marekha BA, Hunger J. Hydrophobic pattern of alkylated ureas markedly affects water rotation and hydrogen bond dynamics in aqueous solution. Phys Chem Chem Phys 2019; 21:20672-20677. [PMID: 31508638 DOI: 10.1039/c9cp04108g] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Alkylated ureas are frequently used amphiphiles to mediate biomolecule water interactions, yet their hydrophobic substitution pattern critically affects their function. These differences can be traced back to their hydration, which is poorly understood. Here, we investigate subtle effects of the hydrophobic pattern of ureas on hydration dynamics using a combination of linear and non-linear infrared spectroscopies on the OD stretching vibration of HDO. Isomeric 1,3-dimethylurea (1,3-DMU), 1,1-dimethylurea (1,1-DMU) and 1-ethylurea (1-EU) exhibit very similar and rather weak modulation of the water hydrogen-bond strength distribution. Yet, only 1,3-DMU and 1,1-DMU enhance the hydrogen-bond heterogeneity and slow-down its fluctuation dynamics. In turn, rotational dynamics of water molecules, which is dominated by hydrogen bond switches, is significantly impeded in the presence of 1,3-DMU and only weakly by 1,1-DMU and 1-EU. These marked differences can be explained by both excluded volume effects in hydration and self-aggregation, which may be the key to their biotechnological function.
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Affiliation(s)
- Bogdan A Marekha
- Molecular Spectroscopy Department, Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany.
| | - Johannes Hunger
- Molecular Spectroscopy Department, Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany.
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Zhang J, Liu L, Chen Y, Wang B, Ouyang C, Tian Z, Gu J, Zhang X, He M, Han J, Zhang W. Water Dynamics in the Hydration Shell of Amphiphilic Macromolecules. J Phys Chem B 2019; 123:2971-2977. [DOI: 10.1021/acs.jpcb.9b02040] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Jiaqi Zhang
- Center for Terahertz Waves and College of Precision Instrument and Optoelectronics Engineering, and Key Laboratory of Optoelectronics Information and Technology, Ministry of Education, Tianjin University, Tianjin 300072, China
| | - Liyuan Liu
- Center for Terahertz Waves and College of Precision Instrument and Optoelectronics Engineering, and Key Laboratory of Optoelectronics Information and Technology, Ministry of Education, Tianjin University, Tianjin 300072, China
| | - Yu Chen
- Tianjin Key Laboratory of Molecular Optoelectronic Science, Department of Chemistry, School of Sciences, Tianjin University, Tianjin 300354, China
| | - Bin Wang
- Tianjin Engineering Technology Center of Chemical Wastewater Source Reduction and Recycling, School of Science, Tianjin Chengjian University, Tianjin 300384, P. R. China
| | - Chunmei Ouyang
- Center for Terahertz Waves and College of Precision Instrument and Optoelectronics Engineering, and Key Laboratory of Optoelectronics Information and Technology, Ministry of Education, Tianjin University, Tianjin 300072, China
| | - Zhen Tian
- Center for Terahertz Waves and College of Precision Instrument and Optoelectronics Engineering, and Key Laboratory of Optoelectronics Information and Technology, Ministry of Education, Tianjin University, Tianjin 300072, China
| | - Jianqiang Gu
- Center for Terahertz Waves and College of Precision Instrument and Optoelectronics Engineering, and Key Laboratory of Optoelectronics Information and Technology, Ministry of Education, Tianjin University, Tianjin 300072, China
| | - Xueqian Zhang
- Center for Terahertz Waves and College of Precision Instrument and Optoelectronics Engineering, and Key Laboratory of Optoelectronics Information and Technology, Ministry of Education, Tianjin University, Tianjin 300072, China
| | - Mingxia He
- Center for Terahertz Waves and College of Precision Instrument and Optoelectronics Engineering, and Key Laboratory of Optoelectronics Information and Technology, Ministry of Education, Tianjin University, Tianjin 300072, China
| | - Jiaguang Han
- Center for Terahertz Waves and College of Precision Instrument and Optoelectronics Engineering, and Key Laboratory of Optoelectronics Information and Technology, Ministry of Education, Tianjin University, Tianjin 300072, China
| | - Weili Zhang
- Center for Terahertz Waves and College of Precision Instrument and Optoelectronics Engineering, and Key Laboratory of Optoelectronics Information and Technology, Ministry of Education, Tianjin University, Tianjin 300072, China
- School of Electrical and Computer Engineering, Oklahoma State University, Stillwater, Oklahoma 74078, United States
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