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McNamara L, Waldron A, Thomas M, Jones W, O'Rourke P, Darrell S, Strange Fessler KA. Investigating the hydrolysis of cryogenically layered molybdenum hexafluoride through a disordered hydrogen-bonded network. Phys Chem Chem Phys 2023; 25:2990-2998. [PMID: 36606495 DOI: 10.1039/d2cp04147b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Molybdenum hexafluoride (MoF6) is used as a non-radioactive substitute for uranium to study the hydrolysis of metal hexafluorides. Molybdenum hexafluoride gas and water vapor, from the air, were sequentially layered onto a diamond substrate kept at liquid nitrogen temperature using a custom designed cryogenic cell with a copper cold finger. Reaction progress was monitored by transmission Fourier Transform Infrared Spectroscopy (FTIR) through the layers and diamond substrate over several hours while allowing the substrate to warm. Changes in the modes in the 500-1000 cm-1 region are tracked as the reaction progresses in order to identify intermediate species. Strong absorption features are also observed in the 1000-3000 cm-1 range, suggesting the presence of ionic dissociation intermediates trapped in a disordered H-bonded network of cryogenic hydrofluoric acid. A possible reaction pathway is proposed and the final hydrolysis product is characterized by FTIR, UV-vis, and scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM/EDS).
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Affiliation(s)
- Louis McNamara
- Savannah River National Laboratory, 301 Gateway Drive, Aiken, 29803, SC, USA.
| | - Abigail Waldron
- Savannah River National Laboratory, 301 Gateway Drive, Aiken, 29803, SC, USA.
| | - Michael Thomas
- Savannah River National Laboratory, 301 Gateway Drive, Aiken, 29803, SC, USA.
| | - Willis Jones
- Savannah River National Laboratory, 301 Gateway Drive, Aiken, 29803, SC, USA. .,University of North Florida, 1 UNF Drive, Jacksonville, FL, 32224, USA
| | - Patrick O'Rourke
- Savannah River National Laboratory, 301 Gateway Drive, Aiken, 29803, SC, USA.
| | - Simmons Darrell
- Oak Ridge National Laboratory, 1 Bethel Valley Road, Oak Ridge, 37830, TN, USA
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2
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Apostolidou C. Vibrational Spectra of the OH Radical in Water: Ab Initio Molecular Dynamics Simulations and Quantum Chemical Calculations Using Hybrid Functionals. ADVANCED THEORY AND SIMULATIONS 2020. [DOI: 10.1002/adts.202000174] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Christina Apostolidou
- Mulliken Center for Theoretical Chemistry Institute of Physical and Theoretical Chemistry Rheinische Friedrich‐Wilhelms‐Universität Bonn Beringstraße 4 Bonn 53115 Germany
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3
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Shalaev E, Soper A, Zeitler JA, Ohtake S, Roberts CJ, Pikal MJ, Wu K, Boldyreva E. Freezing of Aqueous Solutions and Chemical Stability of Amorphous Pharmaceuticals: Water Clusters Hypothesis. J Pharm Sci 2018; 108:36-49. [PMID: 30055227 DOI: 10.1016/j.xphs.2018.07.018] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2018] [Revised: 07/13/2018] [Accepted: 07/17/2018] [Indexed: 11/24/2022]
Abstract
Molecular mobility has been traditionally invoked to explain physical and chemical stability of diverse pharmaceutical systems. Although the molecular mobility concept has been credited with creating a scientific basis for stabilization of amorphous pharmaceuticals and biopharmaceuticals, it has become increasingly clear that this approach represents only a partial description of the underlying fundamental principles. An additional mechanism is proposed herein to address 2 key questions: (1) the existence of unfrozen water (i.e., partial or complete freezing inhibition) in aqueous solutions at subzero temperatures and (2) the role of water in the chemical stability of amorphous pharmaceuticals. These apparently distant phenomena are linked via the concept of water clusters. In particular, freezing inhibition is associated with the confinement of water clusters in a solidified matrix of an amorphous solute, with nanoscaled water clusters being observed in aqueous glasses using wide-angle neutron scattering. The chemical instability is suggested to be directly related to the catalysis of proton transfer by water clusters, considering that proton transfer is the key elementary reaction in many chemical processes, including such common reactions as hydrolysis and deamidation.
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Affiliation(s)
- Evgenyi Shalaev
- Pharmaceutical Development, Allergan plc., Irvine, California 92612.
| | - Alan Soper
- ISIS Facility, UKRI-STFC Rutherford Appleton Laboratory, Harwell Campus, Didcot, Oxon OX11 OQX, UK
| | - J Axel Zeitler
- Department of Chemical Engineering and Biotechnology, University of Cambridge, Philippa Fawcett Drive, Cambridge CB3 0AS, UK
| | - Satoshi Ohtake
- Pfizer BioTherapeutics Pharmaceutical Sciences, Chesterfield, Missouri 63198
| | | | - Michael J Pikal
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Connecticut, Storrs, Connecticut 06269
| | - Ke Wu
- Pharmaceutical Development, Allergan plc., Irvine, California 92612
| | - Elena Boldyreva
- Novosibirsk State University, Pirogova Street 2, Novosibirsk 630090, Russian Federation; Boreskov Institute of Catalysis SB RAS, Novosibirsk 630090, Russian Federation
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4
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Pines D, Nibbering ETJ, Pines E. Monitoring the Microscopic Molecular Mechanisms of Proton Transfer in Acid-base Reactions in Aqueous Solutions. Isr J Chem 2015. [DOI: 10.1002/ijch.201500057] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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5
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Mella M, Curotto E. Quantum simulations of the hydrogen molecule on ammonia clusters. J Chem Phys 2013; 139:124319. [PMID: 24089779 DOI: 10.1063/1.4821648] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Mixed ammonia-hydrogen molecule clusters [H2-(NH3)n] have been studied with the aim of exploring the quantitative importance of the H2 quantum motion in defining their structure and energetics. Minimum energy structures have been obtained employing genetic algorithm-based optimization methods in conjunction with accurate pair potentials for NH3-NH3 and H2-NH3. These include both a full 5D potential and a spherically averaged reduced surface mimicking the presence of a para-H2. All the putative global minima for n ≥ 7 are characterized by H2 being adsorbed onto a rhomboidal ammonia tetramer motif formed by two double donor and two double acceptor ammonia molecules. In a few cases, the choice of specific rhombus seems to be directed by the vicinity of an ammonia ad-molecule. Diffusion Monte Carlo simulations on a subset of the species obtained highlighted important quantum effects in defining the H2 surface distribution, often resulting in populating rhomboidal sites different from the global minimum one, and showing a compelling correlation between local geometrical features and the relative stability of surface H2. Clathrate-like species have also been studied and suggested to be metastable over a broad range of conditions if formed.
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Affiliation(s)
- Massimo Mella
- Dipartimento di Scienze ed Alta Tecnologia, Università degli Studi dell'Insubria, via Valleggio 11, 22100 Como, Italy
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6
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Sigalov MV, Kalish N, Carmeli B, Pines D, Pines E. Probing Small Protonated Water Clusters in Acetonitrile Solutions by 1H NMR. ACTA ACUST UNITED AC 2013. [DOI: 10.1524/zpch.2013.0399] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Abstract
In a previous publication by Kalish et al. (J. Phys. Chem. A 115 (2011) 4063) the existence of well defined small protonated water clusters in acetonitrile has been established by IR spectroscopy. Here we report on a 1H NMR study of triflic acid, CF3SO3H, in acetonitrile-water solutions. Using NMR we are able to corroborate the general solvation scheme we have proposed for the hydrated proton in acetonitrile as a function of the molar ratio between the strong mineral acid and water, n = [H2O]/[acid]. According to this scheme, backed now by both IR absorption spectroscopy and NMR measurements, the very strong triflic acid completely dissociates in acetonitrile/water solutions to yield the aqueous proton and the triflate anion when n > 1. Furthermore, increasing n results in the proton solvated in increasingly larger water clusters formed within the acetonitrile solution.
Clearly distinguishable by NMR are the smallest protonated water clusters, the protonated water monomer, H3
+O, and the protonated water dimer, H5
+O2, which dominate the solution for n = 1,2,3. For larger n the NMR study indicates the gradual increase of the average protonated water cluster size as a function of n while the proton inner solvation core more closely retaining the characteristics of a deformed protonated water dimer, (H2O-H+⋯OH2)
s
than that of the protonated water monomer (H3
+O)
s
.
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Affiliation(s)
- Mark V. Sigalov
- Ben-Gurion University of the Negev, Department of Chemistry, Beer-Sheva 84125, Israel
| | - Noah Kalish
- Ben-Gurion University of the Negev, Department of Chemistry, Beer-Sheva 84125, Israel
| | - Benny Carmeli
- Ben-Gurion University of the Negev, Department of Chemistry, Beer-Sheva 84125, Israel
| | - Dina Pines
- Ben-Gurion University of the Negev, Department of Chemistry, Beer-Sheva 84125, Israel
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Thomas M, Brehm M, Fligg R, Vöhringer P, Kirchner B. Computing vibrational spectra from ab initio molecular dynamics. Phys Chem Chem Phys 2013; 15:6608-22. [DOI: 10.1039/c3cp44302g] [Citation(s) in RCA: 319] [Impact Index Per Article: 29.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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8
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Amorphous trehalose dihydrate by cryogenic milling. Carbohydr Res 2011; 346:1061-4. [DOI: 10.1016/j.carres.2011.03.011] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2010] [Revised: 02/24/2011] [Accepted: 03/06/2011] [Indexed: 11/22/2022]
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Ayotte P, Marchand P, Daschbach JL, Smith RS, Kay BD. HCl Adsorption and Ionization on Amorphous and Crystalline H2O Films below 50 K. J Phys Chem A 2011; 115:6002-14. [DOI: 10.1021/jp110398j] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- Patrick Ayotte
- Département de Chimie, Université de Sherbrooke, 2500 Boulevard Université, Sherbrooke, Québec, Canada J1K 2R1
| | - Patrick Marchand
- Département de Chimie, Université de Sherbrooke, 2500 Boulevard Université, Sherbrooke, Québec, Canada J1K 2R1
| | - John L. Daschbach
- Fundamental and Computational Sciences Directorate, Pacific Northwest National Laboratory, P.O. Box 999, Mail Stop K8-88, Richland, Washington 99352, United States
| | - R. Scott Smith
- Fundamental and Computational Sciences Directorate, Pacific Northwest National Laboratory, P.O. Box 999, Mail Stop K8-88, Richland, Washington 99352, United States
| | - Bruce D. Kay
- Fundamental and Computational Sciences Directorate, Pacific Northwest National Laboratory, P.O. Box 999, Mail Stop K8-88, Richland, Washington 99352, United States
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Kalish NBM, Shandalov E, Kharlanov V, Pines D, Pines E. Apparent stoichiometry of water in proton hydration and proton dehydration reactions in CH3CN/H2O solutions. J Phys Chem A 2011; 115:4063-75. [PMID: 21417385 DOI: 10.1021/jp110873t] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Gradual solvation of protons by water is observed in liquids by mixing strong mineral acids with various amounts of water in acetonitrile solutions, a process which promotes rapid dissociation of the acids in these solutions. The stoichiometry of the reaction XH(+) + n(H(2)O) = X + (H(2)O)(n)H(+) was studied for strong mineral acids (negatively charged X, X = ClO(4)¯, Cl¯, Br¯, I¯, CF(3)SO(3)¯) and for strong cationic acids (uncharged X, X = R*NH(2), H(2)O). We have found by direct quantitative analysis preference of n = 2 over n = 1 for both groups of proton transfer reactions at relatively low water concentrations in acetonitrile. At high water concentrations, we have found that larger water solvates must also be involved in the solvation of the proton while the spectral features already observed for n = 2, H(+)(H(2)O)(2), remain almost unchanged at large n values up to at least 10 M of water.
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Buch V, Dubrovskiy A, Mohamed F, Parrinello M, Sadlej J, Hammerich AD, Devlin JP. HCl hydrates as model systems for protonated water. J Phys Chem A 2008; 112:2144-61. [PMID: 18288820 DOI: 10.1021/jp076391m] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Ab initio molecular dynamics simulations are presented of vibrational dynamics and spectra of crystal HCl hydrates. Depending on the composition, the hydrates include distinct protonated water forms, which in their equilibrium structures approximate either the Eigen ion H3O+(H2O)3 (in the hexahydrate) or the Zundel H2O...H+...OH2 ion (in the di- and trihydrate). Thus, the hydrates offer the opportunity to study spectra and dynamics of distinct species of protonated water trapped in a semirigid solvating environment. The experimentally measured spectra are reproduced quite well by BLYP/DZVP-level calculations employing Fourier transform of the system dipole. The large overall width (800-1000 cm-1) of structured proton bands reflects a broad range of solvating environments generated by crystal vibrations. The aqueous HCl solution was also examined in search of an objective criterion for separating the contributions of "Zundel-like" and "Eigen-like" protonated forms. It is suggested that no such criterion exists since distributions of proton-related structural properties appear continuous and unimodal. Dipole derivatives with respect to OH and O...H+ stretches in water and protonated water were also investigated to advance the understanding of the corresponding IR intensities. The effects of H bonding and solvation on the intensities were analyzed with the help of the Wannier centers' representation of electron density.
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12
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Thar J, Zahn S, Kirchner B. When is a molecule properly solvated by a continuum model or in a cluster ansatz? A first-principles simulation of alanine hydration. J Phys Chem B 2008; 112:1456-64. [PMID: 18193863 DOI: 10.1021/jp077341k] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
In order to test the validity of the cluster ansatz approach as well as of the continuum model approach and to learn about the solvation shell, we carried out first-principles molecular dynamics simulations of the alanine hydration. Our calculations contained one alanine molecule dissolved in 60 water molecules. Dipole moments of individual molecules were derived by means of maximally localized Wannier functions. We observed an average dipole moment of about 16.0 D for alanine and of about 3.3 D for water. In particular, the average water dipole moment in proximity of alanine's COO(-) group decayed continously with increasing distance, while, surprisingly, close to the CH3 and NH3+ group, the dipole moment first rose before its value dropped. In a cluster ansatz approach, we considered snapshots of alanine surrounded by different water molecule shells. The dipole moments from the cluster approaches utilizing both maximally localized Wannier functions as well as natural population analysis served to approximate the dipole moments of the total trajectory. Sufficient convergence of the cluster ansatz approach is found for either of the two solvent shells around the polar groups and one solvent shell around the apolar groups or two solvent shells around the polar groups surrounded by a dieletric continuum.
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Affiliation(s)
- Jens Thar
- Lehrstuhl für Theoretische Chemie, Wilhelm-Ostwald-Institut für Physikalische und Theoretische Chemie, Universität Leipzig, Linnéstr. 2, D-04103 Leipzig, Germany
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13
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Ayotte P, Plessis S, Marchand P. Trapping proton transfer intermediates in the disordered hydrogen-bonded network of cryogenic hydrofluoric acid solutions. Phys Chem Chem Phys 2008; 10:4785-92. [DOI: 10.1039/b806654j] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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14
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Ndongmouo UFT, Lee MS, Rousseau R, Baletto F, Scandolo S. Finite-Temperature Effects on the Stability and Infrared Spectra of HCl(H2O)6 Clusters. J Phys Chem A 2007; 111:12810-5. [DOI: 10.1021/jp0765603] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- U. F. T. Ndongmouo
- The Abdus Salam International Centre for Theoretical Physics, Trieste, I-34014 Italy, Centre for modeling and simulation, and Department of Physics, University of Pune, Ganeshkhind, Pune 411 007, India, International School For Advanced Studies (SISSA), Trieste, I-34014 Italy, DMSE-MIT, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, and INFM/CNR “Democritos” National Simulation Center, Trieste, Italy
| | - M.-S. Lee
- The Abdus Salam International Centre for Theoretical Physics, Trieste, I-34014 Italy, Centre for modeling and simulation, and Department of Physics, University of Pune, Ganeshkhind, Pune 411 007, India, International School For Advanced Studies (SISSA), Trieste, I-34014 Italy, DMSE-MIT, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, and INFM/CNR “Democritos” National Simulation Center, Trieste, Italy
| | - R. Rousseau
- The Abdus Salam International Centre for Theoretical Physics, Trieste, I-34014 Italy, Centre for modeling and simulation, and Department of Physics, University of Pune, Ganeshkhind, Pune 411 007, India, International School For Advanced Studies (SISSA), Trieste, I-34014 Italy, DMSE-MIT, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, and INFM/CNR “Democritos” National Simulation Center, Trieste, Italy
| | - F. Baletto
- The Abdus Salam International Centre for Theoretical Physics, Trieste, I-34014 Italy, Centre for modeling and simulation, and Department of Physics, University of Pune, Ganeshkhind, Pune 411 007, India, International School For Advanced Studies (SISSA), Trieste, I-34014 Italy, DMSE-MIT, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, and INFM/CNR “Democritos” National Simulation Center, Trieste, Italy
| | - S. Scandolo
- The Abdus Salam International Centre for Theoretical Physics, Trieste, I-34014 Italy, Centre for modeling and simulation, and Department of Physics, University of Pune, Ganeshkhind, Pune 411 007, India, International School For Advanced Studies (SISSA), Trieste, I-34014 Italy, DMSE-MIT, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, and INFM/CNR “Democritos” National Simulation Center, Trieste, Italy
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