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Koyakkat M, Ishida T, Fujita K, Shirota H. Low-Frequency Spectra of Hydrated Ionic Liquids with Kosmotropic and Chaotropic Anions. J Phys Chem B 2024; 128:4171-4182. [PMID: 38640467 DOI: 10.1021/acs.jpcb.4c01255] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/21/2024]
Abstract
In this study, we investigated the water concentration dependence of the intermolecular vibrations of two hydrated ionic liquids (ILs), cholinium dihydrogen phosphate ([ch][dhp]) and cholinium bromide ([ch]Br), using femtosecond Raman-induced Kerr effect spectroscopy (fs-RIKES). The anions of the former and latter hydrated ILs are kosmotropic and chaotropic, respectively. We found that the spectral peak of ∼50 cm-1 shifted to the low-frequency side in hydrated [ch][dhp], indicating the weakening of its intermolecular interactions. In contrast, no change in the peak frequency of the low-frequency band at ∼50 cm-1 was observed with increasing water concentration in hydrated [ch]Br. The vibrational density of states (VDOS) spectra generated from molecular dynamics (MD) simulations were in qualitative agreement with the experimental results. Decomposition analysis of the VDOS spectra for each component revealed that the red shift of the low-frequency band in the hydrated [ch][dhp] upon water addition was essentially due to the contributions of anions and water rather than that of the cholinium cation. We also found from the low-frequency spectra of the two hydrated ILs that they differed in the concentration dependence of the 180 cm-1 band, which is assigned as a hindered translational motion of water molecules combined to form O···O stretching motions. From the relationship between the peak frequency of the low-frequency band and the bulk parameter, which is the square root of the surface tension divided by the density, we found that the peak frequency in the hydrated IL with kosmotropic [dhp]- depends on the bulk parameter, similar to the case for an aqueous solution of the typical deep eutectic solvent reline. However, the peak frequency of the hydrated IL with chaotropic Br- is constant with the bulk parameter.
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Affiliation(s)
- Maharoof Koyakkat
- Department of Chemistry, Chiba University, 1-33 Yayoi, Inage-ku, Chiba 263-8522, Japan
| | - Tateki Ishida
- Institute for Molecular Science and Research Center for Computational Science, 38 Nishigo-Naka, Myodaiji, Okazaki 444-8585, Japan
| | - Kyoko Fujita
- Department of Pathophysiology, Tokyo University of Pharmacy and Life Sciences, 1432-1 Horinouchi, Hachioji, Tokyo 192-0392, Japan
| | - Hideaki Shirota
- Department of Chemistry, Chiba University, 1-33 Yayoi, Inage-ku, Chiba 263-8522, Japan
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2
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Cho YC, Lee S, Wang L, Lee YH, Kim S, Lee HH, Lee JJ, Lee GW. Impact of molecular symmetry on crystallization pathways in highly supersaturated KH 2PO 4 solutions. Nat Commun 2024; 15:3117. [PMID: 38600081 PMCID: PMC11006877 DOI: 10.1038/s41467-024-47503-1] [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: 09/26/2023] [Accepted: 04/01/2024] [Indexed: 04/12/2024] Open
Abstract
Solute structure and its evolution in supersaturated aqueous solutions are key clues to understand Ostwald's step rule. Here, we measure the structural evolution of solute molecules in highly supersaturated solutions of KH2PO4 (KDP) and NH4H2PO4 (ADP) using a combination of electrostatic levitation and synchrotron X-ray scattering. The measurement reveals the existence of a solution-solution transition in KDP solution, caused by changing molecular symmetries and structural evolution of the solution with supersaturation. Moreover, we find that the molecular symmetry of H2PO4- impacts on phase selection. These findings manifest that molecular symmetry and its structural evolution can govern the crystallization pathways in aqueous solutions, explaining the microscopic origin of Ostwald's step rule.
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Affiliation(s)
- Yong Chan Cho
- Frontier of Extreme Physics, Korea Research Institute of Standards and Science, Daejeon, 34113, Republic of Korea
| | - Sooheyong Lee
- Frontier of Extreme Physics, Korea Research Institute of Standards and Science, Daejeon, 34113, Republic of Korea
- Applied Measurement Science, University of Science and Technology, Daejeon, 34113, Republic of Korea
| | - Lei Wang
- Frontier of Extreme Physics, Korea Research Institute of Standards and Science, Daejeon, 34113, Republic of Korea
| | - Yun-Hee Lee
- Frontier of Extreme Physics, Korea Research Institute of Standards and Science, Daejeon, 34113, Republic of Korea
| | - Seongheun Kim
- Pohang Accelerator Laboratory, POSTECH, Pohang, 37673, Republic of Korea
| | - Hyun-Hwi Lee
- Pohang Accelerator Laboratory, POSTECH, Pohang, 37673, Republic of Korea
| | - John Jonghyun Lee
- Department of Mechanical Engineering, Iowa State University, Ames, IA, 50011, USA
| | - Geun Woo Lee
- Frontier of Extreme Physics, Korea Research Institute of Standards and Science, Daejeon, 34113, Republic of Korea.
- Applied Measurement Science, University of Science and Technology, Daejeon, 34113, Republic of Korea.
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Gong L, Zhang J, Wang W, Xiang L, Pan M, Yang W, Han L, Wang J, Yan B, Zeng H. Ion-specific effect on self-cleaning performances of polyelectrolyte-functionalized membranes and the underlying nanomechanical mechanism. J Memb Sci 2021. [DOI: 10.1016/j.memsci.2021.119408] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Messias A, Santos DES, Pontes FJS, Soares TA. The tug of war between Al 3+ and Na + for order-disorder transitions in lipid-A membranes. Phys Chem Chem Phys 2021; 23:15127-15137. [PMID: 34254086 DOI: 10.1039/d1cp02173g] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Cations play a critical role in the stability and morphology of lipid-A aggregates by neutralizing, hydrating and cross-linking these glycolipid molecules. Monophosphorylated lipid-A is the major immunostimulatory principle in commercially available adjuvants containing Al3+ such as adjuvant system 04 (AS04). The antagonist/agonist immunomodulatory properties of lipid-A are associated with chemical variations (e.g. the number of acyl chains and phosphate groups) and their aggregate arrangements (e.g. lamellar, nonlamellar or mixed). Therefore, the identification of the active form of lipid-A can provide valuable guidance in the development of vaccine adjuvants capable of boosting the immune system with decreased reactogenicity. Although the effect of mono and divalent cations on the structural polymorphism and endotoxicity of LPS has been previously investigated, much less is known about the effect of trivalent cations. We have investigated the effect of NaCl and AlCl3 salt solutions on the structural dynamics and stability of mono and diphosphorylated lipid-A membranes via atomistic MD simulations. The Al3+ ion exerts two major effects on the structural dynamics of lipid-A membranes. It acts as an efficient cross-linker of mono or diphosphorylated lipid-A molecules, thus stabilizing the lamellar arrangement of these glycolipids. It also alters the lipid-A packing and membrane fluidity, inducing disorder → order structural transitions of the membrane. This effect is promptly reversed upon the addition of NaCl solution, which promotes a nearly threefold increase in the amount of water in the carbohydrate moiety of the Al3+-containing lipid-A membranes. The exchange dynamics and residence times of cation-coordinated water molecules in these membranes provide insights into the molecular mechanism for the Na+-induced transition from a densely packed ordered phase to a disordered one. Al3+ counter-ions favor ordered lamellar aggregates, which has been previously associated with the lack of endotoxic activity and cytokine-inducing action. The resulting microscopic understanding of the structure and dynamics of lipid-A aggregates in the presence of Al3+ and Na+ salts can provide valuable guidance in the development of vaccine adjuvants capable of boosting the immune system with decreased reactogenicity.
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Affiliation(s)
- Andresa Messias
- Department of Fundamental Chemistry, Universidade Federal de Pernambuco, 50740-560 Recife, Brazil.
| | - Denys E S Santos
- Department of Fundamental Chemistry, Universidade Federal de Pernambuco, 50740-560 Recife, Brazil.
| | - Frederico J S Pontes
- Department of Fundamental Chemistry, Universidade Federal de Pernambuco, 50740-560 Recife, Brazil.
| | - Thereza A Soares
- Department of Fundamental Chemistry, Universidade Federal de Pernambuco, 50740-560 Recife, Brazil. and Instituto de Fisica, Universidade de São Paulo, 05508-090 São Paulo, Brazil
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5
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Borah S. Hydration Properties of H nPO 4n-3 (n = 0-3) From Ab Initio Molecular Dynamics Simulations. J Phys Chem B 2020; 124:5454-5464. [PMID: 32484352 DOI: 10.1021/acs.jpcb.0c01769] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
For a comprehensive and detailed microscopic understanding of the hydration properties of primary aqueous phosphorus species of valence states V (viz., H3PO4, H2PO4-, HPO42-, and PO43-), a series of extensive ab initio molecular dynamics simulations is conducted at ambient temperature. In each of these cases, the spatially resolved, three-dimensional hydration shells are computed, allowing for a direct microscopic visual understanding of the hydration shells around the species. Since these species are excellent agents for the formation of hydrogen bonds (H-bonds) in water, which determine a wide range of their structural, dynamic, and spectroscopic features, a detailed analysis of the qualitative and quantitative aspects of the H-bonds, including their lifetime calculations, is performed. Vibrational density of states (VDOS) is calculated for each of the species in solute phases, resolved for each H-bonding site, and compared against the gas-phase normal modes of H3PO4 for the purpose of understanding the signatures of the peaks in VDOS plots and, in particular, the effects of solvation and H-bonding mechanisms. The results are well in line with available experimental data and other recent computer-aided studies in the literature.
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Affiliation(s)
- Sangkha Borah
- Okinawa Institute of Science and Technology Graduate University, 1919-1, Okinawa 904-0412, Japan.,Department of Physics, Indian Institute of Technology Guwahati, Guwahati, Assam 781039, India
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Calzolari A, Pavan B, Curtarolo S, Buongiorno Nardelli M, Fornari M. Vibrational spectral fingerprinting for chemical recognition of biominerals. Chemphyschem 2020; 21:770-778. [PMID: 32107826 DOI: 10.1002/cphc.202000016] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Revised: 02/18/2020] [Indexed: 11/11/2022]
Abstract
Pathologies associated with calcified tissue, such as osteoporosis, demand in vivo and/or in situ spectroscopic analysis to assess the role of chemical substitutions in the inorganic component. High energy X-ray or NMR spectroscopies are impractical or damaging in biomedical conditions. Low energy spectroscopies, such as IR and Raman techniques, are often the best alternative. In apatite biominerals, the vibrational signatures of the phosphate group are generally used as fingerprint of the materials although they provide only limited information. Here, we have used first principles calculations to unravel the complexity of the complete vibrational spectra of apatites. We determined the spectroscopic features of all the phonon modes of fluoroapatite, hydroxy-apatite, and carbonated fluoroapatite beyond the analysis of the phosphate groups, focusing on the effect of local corrections induced by the crystalline environment and the specific mineral composition. This provides a clear and unique reference to discriminate structural and chemical variations in biominerals, opening the way to a widespread application of non-invasive spectroscopies for in vivo diagnostics, and biomedical analysis.
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Affiliation(s)
- Arrigo Calzolari
- CNR-NANO, Istituto Nanoscienze, Centro S3, via Campi 213A, I-41125 Modena, IT and Department of Physics, University of North Texas, Denton, TX 76203, USA
| | - Barbara Pavan
- Department of Chemistry and Science of Advanced Materials Program, Central Michigan University, Mt., Pleasant, MI, 48859, USA
| | - Stefano Curtarolo
- Materials Science, Electrical Engineering, Physics and Chemistry, Duke University, Durham NC, 27708 and Center for Autonomous Materials Design, Duke University, Durham, NC, 27708, USA
| | - Marco Buongiorno Nardelli
- Department of Physics, University of North Texas, Denton, TX 76203, USA and Center for Autonomous Materials Design, Duke University, Durham, NC, 27708, USA
| | - Marco Fornari
- Department of Physics and Science of Advanced Materials Program, Central Michigan University, Mt. Pleasant, MI 48859 USA and Center for Autonomous Materials Design, Duke University, Durham, NC, 27708, USA
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Concentration Dependencies of Diffusion Permeability of Anion-Exchange Membranes in Sodium Hydrogen Carbonate, Monosodium Phosphate, and Potassium Hydrogen Tartrate Solutions. MEMBRANES 2019; 9:membranes9120170. [PMID: 31835564 PMCID: PMC6950726 DOI: 10.3390/membranes9120170] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Revised: 12/04/2019] [Accepted: 12/08/2019] [Indexed: 11/24/2022]
Abstract
The concentration dependencies of diffusion permeability of homogeneous (AMX-Sb and AX) and heterogeneous (MA-41 and FTAM-EDI) anion-exchange membranes (AEMs) is obtained in solutions of ampholytes (sodium bicarbonate, NaHCO3; monosodium phosphate, NaH2PO4; and potassium hydrogen tartrate, KHT) and a strong electrolyte (sodium chloride, NaCl). It is established that the diffusion permeability of AEMs increases with dilution of the ampholyte solutions, while it decreases in the case of the strong electrolyte solution. The factors causing the unusual form of concentration dependencies of AEMs in the ampholyte solutions are considered: (1) the enrichment of the internal AEM solution with multiply charged counterions and (2) the increase in the pore size of AEMs with dilution of the external solution. The enrichment of the internal solution of AEMs with multiply charged counterions is caused by the Donnan exclusion of protons, which are the products of protolysis reactions. The increase in the pore size is conditioned by the stretching of the elastic polymer matrix due to the penetration of strongly hydrated anions of carbonic, phosphoric, and tartaric acids into the AEMs.
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Persson I, Trublet M, Klysubun W. Structure Determination of Phosphoric Acid and Phosphate Ions in Aqueous Solution Using EXAFS Spectroscopy and Large Angle X-ray Scattering. J Phys Chem A 2018; 122:7413-7420. [PMID: 30156411 DOI: 10.1021/acs.jpca.8b05641] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The structures of hydrated phosphoric acid and phosphate ions (H2PO4-, HPO42-, and PO43-) in aqueous solution have been determined by P K-edge EXAFS and large angle X-ray scattering (LAXS). The P-O bond distance in all phosphate species studied is close to 1.53 Å. The P-(O)···Oaq distances have been refined to ca. 3.6 Å from the LAXS data giving a P-O···Oaq bond angle close to tetrahedral, suggesting that each oxygen or OH group of phosphoric acid and dihydrogen phosphate, on average, hydrogen bind three water molecules. The (P-)O(-H)···Oaq and (P-)O···(H-)Oaq hydrogen bonds in hydrated phosphoric acid and the H2PO4- ion are shorter than the hydrogen bonds in neat water. This supports previous infrared spectroscopic studies claiming that the hydrogen bonds in hydrated phosphoric acid and phosphate ions are stronger than the hydrogen bonds in neat water. Phosphoric acid and phosphate ions can therefore be regarded as structure making solutes. This is the first study applying transmission mode X-ray absorption spectroscopy (XAS) data collection on the P K-edge. It shows that XAS spectra collected in transmission mode have a much better S/N ratio than data collected in fluorescence mode, allowing accurate determination of P-O bond distances. Furthermore, P K-edge EXAFS data collected in fluorescence mode display a higher amplitude at high k than expected due to increasing radiated volume of the sample with increasing energy as the total absorption decreases sharply with increasing energy of the X-rays. As a result, the fluorescence signal becomes nonproportional to the intensity of the X-ray beam over the EXAFS spectrum. This results in an increasing amplitude of the EXAFS function with increasing energy of the X-ray beam resulting in too small Debye-Waller coefficients.
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Affiliation(s)
- Ingmar Persson
- Department of Molecular Sciences , Swedish University of Agricultural Sciences , P.O.Box 7015, SE-750 07 Uppsala , Sweden
| | - Mylène Trublet
- Chemical Engineering, Department of Civil, Environmental and Natural Resources Engineering , Luleå University of Technology , SE-971 87 Luleå , Sweden
| | - Wantana Klysubun
- Synchrotron Light Research Institute , 111 Moo 6, University Avenue , Muang , Nakhon Ratchasima 30000 , Thailand
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9
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Biernacki KA, Kaczkowska E, Bruździak P. Aqueous solutions of NMA, Na2HPO4, and NaH2PO4 as models for interaction studies in phosphate–protein systems. J Mol Liq 2018. [DOI: 10.1016/j.molliq.2018.05.104] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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10
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Bruce EE, van der Vegt NFA. Does an electronic continuum correction improve effective short-range ion-ion interactions in aqueous solution? J Chem Phys 2018; 148:222816. [DOI: 10.1063/1.5017101] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Affiliation(s)
- Ellen E. Bruce
- Eduard-Zintl-Institut für Anorganische und Physikalische Chemie, Center of Smart Interfaces, Technische Universität Darmstadt, Alarich-Weiss-Straße 10, D-64287 Darmstadt, Germany
| | - Nico F. A. van der Vegt
- Eduard-Zintl-Institut für Anorganische und Physikalische Chemie, Center of Smart Interfaces, Technische Universität Darmstadt, Alarich-Weiss-Straße 10, D-64287 Darmstadt, Germany
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11
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Kuchuk K, Sivan U. Hydration Structure of a Single DNA Molecule Revealed by Frequency-Modulation Atomic Force Microscopy. NANO LETTERS 2018; 18:2733-2737. [PMID: 29564895 DOI: 10.1021/acs.nanolett.8b00854] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Hydration interaction shapes biomolecules and is a dominant intermolecular force. Mapping the hydration patterns of biomolecules is therefore essential for understanding molecular processes in biology. Numerous studies have been devoted to this challenge, but current methods cannot map the hydration of single biomolecules, let alone do so under physiological conditions. Here, we show that frequency-modulation atomic force microscopy (FM-AFM) can fill this gap and generate 3D hydration maps of single DNA molecules under near-physiological conditions. Additionally, we present real-space images of DNA in which the double helix is resolved with unprecedented resolution, clearly revealing individual phosphate groups along the DNA backbone. FM-AFM therefore emerges as a powerful enabling tool in the study of individual biomolecules and their hydration under physiological conditions.
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Affiliation(s)
- Kfir Kuchuk
- Department of Physics and the Russell Berrie Nanotechnology Institute , Technion - Israel Institute of Technology , Haifa , 3200003 , Israel
| | - Uri Sivan
- Department of Physics and the Russell Berrie Nanotechnology Institute , Technion - Israel Institute of Technology , Haifa , 3200003 , Israel
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12
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Sharma B, Chandra A. Ab Initio Molecular Dynamics Simulation of the Phosphate Ion in Water: Insights into Solvation Shell Structure, Dynamics, and Kosmotropic Activity. J Phys Chem B 2017; 121:10519-10529. [DOI: 10.1021/acs.jpcb.7b06091] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Bikramjit Sharma
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur 208016, India
| | - Amalendu Chandra
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur 208016, India
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13
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The Structure of Water and Aqueous Systems. ACTA ACUST UNITED AC 2017. [DOI: 10.1016/b978-0-12-805324-9.00003-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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14
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DiTucci MJ, Böhm F, Schwaab G, Williams ER, Havenith M. Effects of multivalent hexacyanoferrates and their ion pairs on water molecule dynamics measured with terahertz spectroscopy. Phys Chem Chem Phys 2017; 19:7297-7306. [DOI: 10.1039/c6cp08423k] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Broadband Fourier transform terahertz spectroscopy reveals that dynamical perturbations to the low-frequency dynamics of water molecules by multivalent hexacyanoferrate salts extend beyond the primary solvation shell.
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Affiliation(s)
| | - Fabian Böhm
- Department of Physical Chemistry II
- Ruhr-Universität Bochum
- Germany
| | - Gerhard Schwaab
- Department of Physical Chemistry II
- Ruhr-Universität Bochum
- Germany
| | | | - Martina Havenith
- Department of Physical Chemistry II
- Ruhr-Universität Bochum
- Germany
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15
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DiTucci MJ, Williams ER. Nanometer patterning of water by tetraanionic ferrocyanide stabilized in aqueous nanodrops. Chem Sci 2016; 8:1391-1399. [PMID: 28451280 PMCID: PMC5361863 DOI: 10.1039/c6sc03722d] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2016] [Accepted: 10/16/2016] [Indexed: 11/21/2022] Open
Abstract
Formation of the small, highly charged tetraanion ferrocyanide, Fe(CN)64–, stabilized in aqueous nanodrops and its influence to the surrounding hydrogen-bonding network of water is reported.
Formation of the small, highly charged tetraanion ferrocyanide, Fe(CN)64–, stabilized in aqueous nanodrops is reported. Ion–water interactions inside these nanodrops are probed using blackbody infrared radiative dissociation, infrared photodissociation (IRPD) spectroscopy, and molecular modeling in order to determine how water molecules stabilize this highly charged anion and the extent to which the tetraanion patterns the hydrogen-bonding network of water at long distance. Fe(CN)64–(H2O)38 is the smallest cluster formed directly by nanoelectrospray ionization. Ejection of an electron from this ion to form Fe(CN)63–(H2O)38 occurs with low-energy activation, but loss of a water molecule is favored at higher energy indicating that water molecule loss is entropically favored over loss of an electron. The second solvation shell is almost complete at this cluster size indicating that nearly two solvent shells are required to stabilize this highly charged anion. The extent of solvation necessary to stabilize these clusters with respect to electron loss is substantially lower through ion pairing with either H+ or K+ (n = 17 and 18, respectively). IRPD spectra of Fe(CN)64–(H2O)n show the emergence of a free O–H water molecule stretch between n = 142 and 162 indicating that this ion patterns the structure of water molecules within these nanodrops to a distance of at least ∼1.05 nm from the ion. These results provide new insights into how water stabilizes highly charged ions and demonstrate that highly charged anions can have a significant effect on the hydrogen-bonding network of water molecules well beyond the second and even third solvation shells.
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Affiliation(s)
- Matthew J DiTucci
- Department of Chemistry , University of California , B42 Hildebrand Hall , Berkeley , CA 94270 , USA .
| | - Evan R Williams
- Department of Chemistry , University of California , B42 Hildebrand Hall , Berkeley , CA 94270 , USA .
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16
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Zhou HW, Burger C, Wang H, Hsiao BS, Chu B, Graham L. The supramolecular structure of bone: X-ray scattering analysis and lateral structure modeling. Acta Crystallogr D Struct Biol 2016; 72:986-96. [PMID: 27599731 PMCID: PMC5013594 DOI: 10.1107/s2059798316011864] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2015] [Accepted: 07/20/2016] [Indexed: 11/10/2022] Open
Abstract
The evolution of vertebrates required a key development in supramolecular evolution: internally mineralized collagen fibrils. In bone, collagen molecules and mineral crystals form a nanocomposite material comparable to cast iron in tensile strength, but several times lighter and more flexible. Current understanding of the internal nanoscale structure of collagen fibrils, derived from studies of rat tail tendon (RTT), does not explain how nucleation and growth of mineral crystals can occur inside a collagen fibril. Experimental obstacles encountered in studying bone have prevented a solution to this problem for several decades. This report presents a lateral packing model for collagen molecules in bone fibrils, based on the unprecedented observation of multiple resolved equatorial reflections for bone tissue using synchrotron small-angle X-ray scattering (SAXS; ∼1 nm resolution). The deduced structure for pre-mineralized bone fibrils includes features that are not present in RTT: spatially discrete microfibrils. The data are consistent with bone microfibrils similar to pentagonal Smith microfibrils, but are not consistent with the (nondiscrete) quasi-hexagonal microfibrils reported for RTT. These results indicate that collagen fibrils in bone and tendon differ in their internal structure in a manner that allows bone fibrils, but not tendon fibrils, to internally mineralize. In addition, the unique pattern of collagen cross-link types and quantities in mineralized tissues can be can be accounted for, in structural/functional terms, based on a discrete microfibril model.
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Affiliation(s)
- Hong-Wen Zhou
- Department of Chemistry, Stony Brook University, Stony Brook, NY 11794-3400, USA
| | - Christian Burger
- Department of Chemistry, Stony Brook University, Stony Brook, NY 11794-3400, USA
| | - Hao Wang
- Laboratory for the Study of Skeletal Disorders and Rehabilitation, Children’s Hospital Boston, Boston, MA 02115, USA
- Harvard Medical School, Boston, MA 02115, USA
| | - Benjamin S. Hsiao
- Department of Chemistry, Stony Brook University, Stony Brook, NY 11794-3400, USA
| | - Benjamin Chu
- Department of Chemistry, Stony Brook University, Stony Brook, NY 11794-3400, USA
| | - Lila Graham
- Laboratory for the Study of Skeletal Disorders and Rehabilitation, Children’s Hospital Boston, Boston, MA 02115, USA
- Harvard Medical School, Boston, MA 02115, USA
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18
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Costard R, Tyborski T, Fingerhut BP, Elsaesser T. Ultrafast phosphate hydration dynamics in bulk H2O. J Chem Phys 2015; 142:212406. [DOI: 10.1063/1.4914152] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Affiliation(s)
- Rene Costard
- Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie, D-12489 Berlin, Germany
| | - Tobias Tyborski
- Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie, D-12489 Berlin, Germany
| | - Benjamin P. Fingerhut
- Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie, D-12489 Berlin, Germany
| | - Thomas Elsaesser
- Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie, D-12489 Berlin, Germany
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Eiberweiser A, Nazet A, Hefter G, Buchner R. Ion hydration and association in aqueous potassium phosphate solutions. J Phys Chem B 2015; 119:5270-81. [PMID: 25826464 DOI: 10.1021/acs.jpcb.5b01417] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Ionic hydration and ion association in aqueous solutions of KH2PO4, K2HPO4, and K3PO4 at 25 °C up to high concentrations have been investigated using dielectric relaxation spectroscopy (DRS). The three phosphate anions were found to be extensively hydrated, with total hydration numbers at infinite dilution of ~11 (for H2PO4(-)), ~20 (HPO4(2-)), and ~39 (PO4(3-)). These values are indicative of the existence of a second hydration shell around HPO4(2-) and especially PO4(3-). Two types of hydrating water molecules could be quantified: irrotationally bound (ib, H2O molecules essentially "frozen" on the DRS time scale) and "slow" (loosely bound water molecules with identifiably slower dynamics than bulk water). For H2PO4(-) over the entire concentration range and for HPO4(2-) and PO4(3-) at concentrations c ≲ 1 mol L(-1), only "slow" H2O was detected; however, at higher concentrations of the latter two anions, an increasing fraction of ib water appears, making up ~50% of the total hydration number close to the saturation limit of K2HPO4. Contrary to common belief, all three salts showed significant ion pair formation, with standard association constants of the 1:1 species increasing in the order: KH2PO4(0)(aq) < KHPO4(-)(aq) < KPO4(2-)(aq). The main type of ion pair in solution shifted from solvent-shared ion pairs (SIPs) to double-solvent-separated ion pairs (2SIPs) in the same sequence.
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Affiliation(s)
- Andreas Eiberweiser
- †Institut für Physikalische und Theoretische Chemie, Universität Regensburg, Universitätsstr. 31, D-93040 Regensburg, Germany
| | - Andreas Nazet
- †Institut für Physikalische und Theoretische Chemie, Universität Regensburg, Universitätsstr. 31, D-93040 Regensburg, Germany
| | - Glenn Hefter
- ‡Chemistry Department, Murdoch University, 90 South Street, Murdoch, WA 6150, Australia
| | - Richard Buchner
- †Institut für Physikalische und Theoretische Chemie, Universität Regensburg, Universitätsstr. 31, D-93040 Regensburg, Germany
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Sun ST, Jiang L, Liu J, Heine N, Yacovitch TI, Wende T, Asmis KR, Neumark DM, Liu ZF. Microhydrated dihydrogen phosphate clusters probed by gas phase vibrational spectroscopy and first principles calculations. Phys Chem Chem Phys 2015; 17:25714-24. [DOI: 10.1039/c5cp02253c] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We report infrared multiple photon dissociation spectra of cryogenically-cooled H2PO4−(H2O)n anions (n = 2–12) in the spectral range of the stretching and bending modes of the solute anion (600–1800 cm−1).
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Affiliation(s)
- Shou-Tian Sun
- Department of Chemistry and Centre for Scientific Modeling and Computation
- Chinese University of Hong Kong
- Shatin
- China
| | - Ling Jiang
- Fritz-Haber-Institut der Max-Planck-Gesellschaft
- D-14195 Berlin
- Germany
- State Key Laboratory of Molecular Reaction Dynamics
- Dalian Institute of Chemical Physics
| | - J.W. Liu
- National Supercomputing Center in Shenzhen
- Shenzhen
- China
| | - Nadja Heine
- Fritz-Haber-Institut der Max-Planck-Gesellschaft
- D-14195 Berlin
- Germany
| | | | - Torsten Wende
- Fritz-Haber-Institut der Max-Planck-Gesellschaft
- D-14195 Berlin
- Germany
| | - Knut R. Asmis
- Wilhelm-Ostwald-Institut für Physikalische und Theoretische Chemie
- Universität Leipzig
- D-04103 Leipzig
- Germany
| | - Daniel M. Neumark
- Department of Chemistry
- University of California
- Berkeley
- USA
- Chemical Sciences Division
| | - Zhi-Feng Liu
- Department of Chemistry and Centre for Scientific Modeling and Computation
- Chinese University of Hong Kong
- Shatin
- China
- Shenzhen Research Institute
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Ahmed M, Namboodiri V, Singh AK, Mondal JA. On the intermolecular vibrational coupling, hydrogen bonding, and librational freedom of water in the hydration shell of mono- and bivalent anions. J Chem Phys 2014; 141:164708. [DOI: 10.1063/1.4899070] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Lyashchenko AK, Lotsmanova EA, Lileev AS. Stabilization of water structure in ammonium hydrogenphosphate solutions. RUSS J INORG CHEM+ 2014. [DOI: 10.1134/s0036023614070134] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Möller J, Grobelny S, Schulze J, Steffen A, Bieder S, Paulus M, Tolan M, Winter R. Specific anion effects on the pressure dependence of the protein–protein interaction potential. Phys Chem Chem Phys 2014; 16:7423-9. [DOI: 10.1039/c3cp55278k] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Pluhařová E, Ončák M, Seidel R, Schroeder C, Schroeder W, Winter B, Bradforth SE, Jungwirth P, Slavíček P. Transforming Anion Instability into Stability: Contrasting Photoionization of Three Protonation Forms of the Phosphate Ion upon Moving into Water. J Phys Chem B 2012; 116:13254-64. [DOI: 10.1021/jp306348b] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Eva Pluhařová
- Institute
of Organic Chemistry
and Biochemistry, Academy of Sciences of the Czech Republic, Flemingovo nám. 2, 16610 Prague 6, Czech Republic
- Department of Physical Chemistry, Institute of Chemical Technology, Technická
5, 16628 Prague 6, Czech Republic
| | - Milan Ončák
- Department of Physical Chemistry, Institute of Chemical Technology, Technická
5, 16628 Prague 6, Czech Republic
| | - Robert Seidel
- Helmholtz-Zentrum Berlin für Materialien und Energie, and BESSY, Albert-Einstein-Strasse 15, D-12489 Berlin, Germany
- Department of Chemistry, University of Southern California, Los Angeles, California
90089-0482, United States
| | - Christi Schroeder
- Department of Chemistry, University of Southern California, Los Angeles, California
90089-0482, United States
| | - William Schroeder
- Department of Chemistry, University of Southern California, Los Angeles, California
90089-0482, United States
| | - Bernd Winter
- Helmholtz-Zentrum Berlin für Materialien und Energie, and BESSY, Albert-Einstein-Strasse 15, D-12489 Berlin, Germany
| | - Stephen E. Bradforth
- Department of Chemistry, University of Southern California, Los Angeles, California
90089-0482, United States
| | - Pavel Jungwirth
- Institute
of Organic Chemistry
and Biochemistry, Academy of Sciences of the Czech Republic, Flemingovo nám. 2, 16610 Prague 6, Czech Republic
| | - Petr Slavíček
- Department of Physical Chemistry, Institute of Chemical Technology, Technická
5, 16628 Prague 6, Czech Republic
- J. Heyrovský Institute of Physical Chemistry, Dolejškova 3,
18223 Prague 8, Czech Republic
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Syed KA, Pang SF, Zhang Y, Zeng G, Zhang YH. Micro-Raman observation on the HPO4(2-) association structures in an individual dipotassium hydrogen phosphate (K2HPO4) droplet. J Phys Chem A 2012; 116:1558-64. [PMID: 22233339 DOI: 10.1021/jp2110743] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
A single K(2)HPO(4) droplet with size of ∼50 μm on a Teflon substrate was forced to enter into the supersaturated state by decreasing the relative humidity (RH), allowing accurate control over the concentration of the solute within a droplet of a nanogram. The K(2)HPO(4) solutions from dilute (0.1-1.0 mol·L(-1) bulk) to concentrated state (a droplet from RH 98.2% to 25.1%) were studied through micro-Raman spectroscopy in the spectral region of about 200-4000 cm(-1). The area ratio between the water stretching band to the sum of the ν(1)-PO(3), ν(2)-POH, and ν(4)-PO(3) bands of the HPO(4)(2-) at various RHs was used to describe the dehydration behavior of a microsized single K(2)HPO(4) droplet in dehumidifying process. The peak position of the v(1)-PO(3) band for the 1 mol·L(-1) bulk solution appeared at 991 cm(-1) and moved to 986 cm(-1) at 98.2% RH, to 978 cm(-1) at 70.2% RH, and then to 964 cm(-1) at 30.0% RH for a droplet, accompanying an increase of the full width at half-height (fwhh) of this peak from 16.3 to 17.2, 22.2, and then to 24.2 cm(-1), indicating transition of the HPO(4)(2-) anions from monomers to dimers/trimers/oligomers and then to polyanions with chain structures in the K(2)HPO(4) solutions. After 25.1% RH, the solid was proved to be K(2)HPO(4)·3H(2)O according to the Raman spectral features. Furthermore, the O-H stretching envelope of a K(2)HPO(4) droplet showed that the intensity ratios of the strong hydrogen bonding component (3255 cm(-1)) to the weak one (3417 cm(-1)) and the cage-like water (2925 cm(-1)) to the weak one (3417 cm(-1)) were sensitive to the HPO(4)(2-) association structures, which can be used to understand the effects of dimers/trimers/oligomers and chain structures of the HPO(4)(2-) associations on the hydrogen bonding of water molecules.
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Affiliation(s)
- Kamran Ajmal Syed
- Key Laboratory of Cluster Science, School of Science, Beijing Institute of Technology, Beijing 100081, China
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Yuchi A, Kuroda S, Takagi M, Watanabe Y, Nakao S. Effects of the Exchange Capacity and Cross-Linking Degree on the Hydration States of Anions in Quantitative Loading onto Strongly Basic Anion-Exchange Resins. Anal Chem 2010; 82:8611-7. [DOI: 10.1021/ac101707j] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Akio Yuchi
- Graduate School of Engineering, Nagoya Institute of Technology, Gokiso, Showa, Nagoya 466-8555, Japan.
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Rudolph WW. Raman- and infrared-spectroscopic investigations of dilute aqueous phosphoric acid solutions. Dalton Trans 2010; 39:9642-53. [DOI: 10.1039/c0dt00417k] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Yokogawa D, Sato H, Sakaki S. Analytical energy gradient for reference interaction site model self-consistent field explicitly including spatial electron density distribution. J Chem Phys 2009; 131:214504. [DOI: 10.1063/1.3265856] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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Smiechowski M, Gojło E, Stangret J. Systematic study of hydration patterns of phosphoric(V) acid and its mono-, di-, and tripotassium salts in aqueous solution. J Phys Chem B 2009; 113:7650-61. [PMID: 19413357 DOI: 10.1021/jp810195h] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Fourier transform infrared (FTIR) spectroscopy of the OD band of HDO molecules has been applied to perform a systematic study of various phosphate forms in the order of decreasing protonation: H3PO4, KH2PO4, K2HPO4, K3PO4. HDO isotopically diluted in H2O has been prepared by adding adequate amounts of D2O to aqueous solutions in ordinary water. The difference spectra procedure has been applied to remove the contribution of bulk water and thus to separate the spectra of solute-affected HDO. The position at maximum of the principal anion-affected HDO band for potassium phosphates moves in the order KH2PO4 (2478 cm(-1))>K2HPO4 (2363 cm(-1))>K3PO4 (2301 cm(-1)), that is, decreases with increasing solute basicity and charge. The number of moles of water affected by one mole of solute (N) equals 11.0, 13.8 and 16.2, respectively. Phosphoric acid affects statistically 13.9 water molecules and appears to be a "structure making" solute in water. The isotopic substitution with deuterium occurs also on the phosphate anions and phosphoric acid. The thus formed P-O-D groups interact with water molecules via strong hydrogen bonds and the relative strength of this interaction increases with increasing solute acidity. The plausible assignments of OD bands of HDO have been confirmed by calculating equilibrium structures of small aqueous clusters of the studied individual utilizing density functional theory. Further interpretation of the energetic and structural properties of hydrating water is enabled by calculating intermolecular interaction energy of water and probability distributions for interatomic oxygen-oxygen distance.
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Affiliation(s)
- Maciej Smiechowski
- Department of Physical Chemistry, Chemical Faculty, Gdańsk University of Technology, Narutowicza 11/12, 80-233 Gdańsk, Poland.
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31
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Tang E, Di Tommaso D, de Leeuw NH. Hydrogen transfer and hydration properties of HnPO43−n (n=0–3) in water studied by first principles molecular dynamics simulations. J Chem Phys 2009; 130:234502. [DOI: 10.1063/1.3143952] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Rouff AA, Rabe S, Nachtegaal M, Vogel F. X-ray Absorption Fine Structure Study of the Effect of Protonation on Disorder and Multiple Scattering in Phosphate Solutions and Solids. J Phys Chem A 2009; 113:6895-903. [DOI: 10.1021/jp811276t] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Ashaki A. Rouff
- General Energy Research (ENE), Laboratory for Energy and Materials Cycles, Paul Scherrer Institut, 5232 Villigen PSI, Switzerland
| | - Stefan Rabe
- General Energy Research (ENE), Laboratory for Energy and Materials Cycles, Paul Scherrer Institut, 5232 Villigen PSI, Switzerland
| | - Maarten Nachtegaal
- General Energy Research (ENE), Laboratory for Energy and Materials Cycles, Paul Scherrer Institut, 5232 Villigen PSI, Switzerland
| | - Frédéric Vogel
- General Energy Research (ENE), Laboratory for Energy and Materials Cycles, Paul Scherrer Institut, 5232 Villigen PSI, Switzerland
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33
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Theoretical calculation of pKas of phosphoric (V) acid in the polarisable continuum and cluster-continuum models. J Mol Struct 2009. [DOI: 10.1016/j.molstruc.2008.11.047] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Pribil AB, Hofer TS, Randolf BR, Rode BM. Structure and dynamics of phosphate ion in aqueous solution: an ab initio QMCF MD study. J Comput Chem 2008; 29:2330-4. [PMID: 18473325 DOI: 10.1002/jcc.20968] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
A simulation of phosphate in aqueous solution was carried out employing the new QMCF MD approach which offers the possibility to investigate composite systems with the accuracy of a QMMM method but without the time consuming creation of solute-solvent potential functions. The data of the simulations give a clear picture of the hydration shells of the phosphate anion. The first shell consists of 13 water molecules and each oxygen of the phosphate forms in average three hydrogens bonds to different solvent molecules. Several structural parameters such as radial distribution functions and coordination number distributions allow to fully characterize the embedding of the highly charged phosphate ion in the solvent water. The dynamics of the hydration structure of phosphate are described by mean residence times of the solvent molecules in the first hydration shell and the water exchange rate.
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Affiliation(s)
- Andreas B Pribil
- Theoretical Chemistry Division, Institute of General, Inorganic and Theoretical Chemistry, University of Innsbruck, Innrain 52a, A-6020 Innsbruck, Austria
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Rudolph WW, Irmer G. Raman and infrared spectroscopic investigations on aqueous alkali metal phosphate solutions and density functional theory calculations of phosphate-water clusters. APPLIED SPECTROSCOPY 2007; 61:1312-1327. [PMID: 18198023 DOI: 10.1366/000370207783292037] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Phosphate (PO(4)(3-)) solutions in water and heavy water have been studied by Raman and infrared spectroscopy over a broad concentration range (0.0091-5.280 mol/L) including a hydrate melt at 23 degrees C. In the low wavenumber range, spectra in R-format have been constructed and the R normalization procedure has been briefly discussed. The vibrational modes of the tetrahedral PO(4)(3-)(aq) (T(d) symmetry) have been assigned and compared to the calculated values derived from the density functional theory (DFT) method for the unhydrated PO(4)(3-)(T(d)) and phosphate-water clusters: PO(4)(3-).H(2)O (C(2v)), PO(4)(3-).2H(2)O (D(2d)), PO(4)(3-).4H(2)O (D(2d)), PO(4)(3-).6H(2)O (T(d)), and PO(4)(3-).12H(2)O (T), a cluster with a complete first hydration sphere of water molecules. A cluster with a second hydration sphere of 12 water molecules and 6 in the first sphere, PO(4)(3-).18H(2)O (T), has also been calculated. Agreement between measured and calculated vibrational modes is best in the case of the PO(4)(3-).12H(2)O cluster and the PO(4)(3-).18H(2)O cluster but far less so in the case of the unhydrated PO(4)(3-) or phosphate-water cluster with a lower number of water molecules than 12. The asymmetric, broad band shape of v(1)(a(1)) PO(4)(3-) in aqueous solutions has been measured as a function of concentration and the asymmetric and broad band shape was explained. However, the same mode in heavy water has only half the full width at half-height compared to the mode in normal water. The PO(4)(3-) is strongly hydrated in aqueous solutions. This has been verified by Raman spectroscopy comparing v(2)(H(2)O), the deformation mode of water, and the stretching modes, the v(1)OH and v(3)OH of water, in K(3)PO(4) solutions as a function of concentration and comparison with the same modes in pure water. A mode at approximately 240 cm(-1) (isotropic R spectrum) has been detected and assigned to the restricted translational mode of the strong hydrogen bonds formed between phosphate and water, P-O...HOH. In very concentrated K(3)PO(4) solutions (C(0) > or = 3.70 mol/L) and in the hydrate melt, formation of contact ion pairs (CIPs) could be detected. The phosphate in the CIPs shows a symmetry lowering of the T(d) symmetry to C(3v). In the less concentrated solutions, PO(4)(3-)(aq) solvent separated ion pairs and doubly solvent separated ion pairs exist, while in very dilute solutions fully hydrated ions are present (C(0) < or = 0.005 mol/L). Quantitative Raman measurements have been carried out to follow the hydrolysis of PO(4)(3-)(aq) over a very broad concentration range. From the hydrolysis data, the pK(3) value for H(3)PO(4) has been determined to be 12.45 at 23 degrees C.
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Affiliation(s)
- Wolfram W Rudolph
- Institut für Virologie im MTZ, TU Dresden, Fetscherstr. 74, 01307 Dresden, Germany.
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Brandán SA, Díaz SB, López González JJ, Disalvo EA, Ben Altabef A. Experimental and theoretical study of the hydration of phosphate groups in esters of biological interest. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2007; 66:884-97. [PMID: 16843704 DOI: 10.1016/j.saa.2006.05.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2005] [Revised: 04/30/2006] [Accepted: 05/03/2006] [Indexed: 05/10/2023]
Abstract
We have studied the influence of different groups esterified to phosphates on the strength of the interaction of the PO bond with one water molecule. Experimental vibrational spectra of PO(4)3-, HPO4(2-), H2PO4-, phosphoenolpiruvate (PEP) and ortho-phosphocholamine (o-PC) were obtained by means of FTIR spectroscopy. Geometry calculations were performed using standard gradient techniques and the default convergence criteria as implemented in GAUSSIAN 98 Program. In order to assess the behaviour of such DFT theoretical calculations using B3LYP with 6-31G* and 6-311++G** basis sets, we carried out a comparative work for those compounds. The results were then used to predict the principal bands of the vibrational spectra and molecular parameters (geometrical parameters, stabilisation energies, electronic density). In this work, the relative stability and the nature of the PO bond in those compounds were systematically and quantitatively investigated by means of Natural Bond Order (NBO) analysis. The topological properties of electronic charge density are analysed employing Bader's Atoms in Molecules theory (AIM). The hydrogen bonding of phosphate groups with water is highly stable and the PO bond wavenumbers are shifted to lower experimental and calculated values (with the DFT/6-311++G** basis set). Accordingly, the predicted order of the relative stability of the hydrogen bonding of the water molecule to the PO bond of the investigated compounds is: PO(4)3->HPO4(2-)>H2PO4->phosphoenolpiruvate>phosphocholamine for the two basis sets used.
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Affiliation(s)
- S A Brandán
- Instituto de Química Física, Facultad de Bioquímica, Química y Farmacia, Universidad Nacional de Tucumán, San Lorenzo 456 (4000), Tucumán, Argentina
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Brandán SA, Díaz SB, Picot RC, Disalvo EA, Altabef AB. Hydration of inorganic phosphates in crystal lattices and in aqueous solution. An experimental and theoretical study. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2007; 66:1152-64. [PMID: 16843715 DOI: 10.1016/j.saa.2006.05.029] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/29/2005] [Revised: 05/23/2006] [Accepted: 05/27/2006] [Indexed: 05/10/2023]
Abstract
B3LYP/6-31G* and 6-311++G** calculations have been carried out in order to study the hydration of phosphates in aqueous media. Optimized geometries and relative stabilities for PO4(-3), HPO(4)-2, H2PO4(-1) have been calculated considering the interaction with one, two, three, four and five discrete water molecules and taking into account the solvent effect by using the self-consistent reaction field theory (Onsager and PCM methods). The role of specific and bulk contributions of solvent effect on the observable properties of phosphate compounds is analysed. Good agreement between theoretical and available experimental results of harmonic vibration frequencies is found. Significant effects on the geometrical and vibrational frequencies are found for those studied phosphate anions. The results presented here provide a first step toward the understanding of the phosphate group as a hydration sensor in lipid bilayers.
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Affiliation(s)
- S A Brandán
- Instituto de Química Física, Facultad de Bioquímica, Química y Farmacia, Universidad Nacional de Tucumán, San Lorenzo 456, 4000 Tucumán, Argentina
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