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Majhi D, Stevensson B, Nguyen TM, Edén M. 1H and 13C chemical shift-structure effects in anhydrous β-caffeine and four caffeine-diacid cocrystals probed by solid-state NMR experiments and DFT calculations. Phys Chem Chem Phys 2024; 26:14345-14363. [PMID: 38700003 DOI: 10.1039/d3cp06197c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/05/2024]
Abstract
By using density functional theory (DFT) calculations, we refined the H atom positions in the structures of β-caffeine (C), α-oxalic acid (OA; (COOH)2), α-(COOH)2·2H2O, β-malonic acid (MA), β-glutaric acid (GA), and I-maleic acid (ME), along with their corresponding cocrystals of 2 : 1 (2C-OA, 2C-MA) or 1 : 1 (C-GA, C-ME) stoichiometry. The corresponding 13C/1H chemical shifts obtained by gauge including projector augmented wave (GIPAW) calculations agreed overall very well with results from magic-angle-spinning (MAS) nuclear magnetic resonance (NMR) spectroscopy experiments. Chemical-shift/structure trends of the precursors and cocrystals were examined, where good linear correlations resulted for all COO1H sites against the H⋯O and/or H⋯N H-bond distance, whereas a general correlation was neither found for the aliphatic/caffeine-stemming 1H sites nor any 13C chemical shift against either the intermolecular hydrogen- or tetrel-bond distance, except for the 13COOH sites of the 2C-OA, 2C-MA, and C-GA cocrystals, which are involved in a strong COOH⋯N bond with caffeine that is responsible for the main supramolecular stabilization of the cocrystal. We provide the first complete 13C NMR spectral assignment of the structurally disordered anhydrous β-caffeine polymorph. The results are discussed in relation to previous literature on the disordered α-caffeine polymorph and the ordered hydrated counterpart, along with recommendations for NMR experimentation that will secure sufficient 13C signal-resolution for reliable resonance/site assignments.
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Affiliation(s)
- Debashis Majhi
- Department of Materials and Environmental Chemistry, Stockholm University, SE-106 91, Stockholm, Sweden.
| | - Baltzar Stevensson
- Department of Materials and Environmental Chemistry, Stockholm University, SE-106 91, Stockholm, Sweden.
| | - Tra Mi Nguyen
- Department of Materials and Environmental Chemistry, Stockholm University, SE-106 91, Stockholm, Sweden.
| | - Mattias Edén
- Department of Materials and Environmental Chemistry, Stockholm University, SE-106 91, Stockholm, Sweden.
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2
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Badoni S, Berruyer P, Emsley L. Optimal sensitivity for 1H detected relayed DNP of organic solids at fast MAS. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2024; 360:107645. [PMID: 38401477 DOI: 10.1016/j.jmr.2024.107645] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2023] [Revised: 01/30/2024] [Accepted: 02/09/2024] [Indexed: 02/26/2024]
Abstract
Dynamic nuclear polarization (DNP) combined with high magnetic fields and fast magic angle spinning (MAS) has opened up a new avenue for the application of exceptionally sensitive 1H NMR detection schemes to study protonated solids. Recently, it has been shown that DNP experiments at fast MAS rates lead to slower spin diffusion and hence reduced DNP enhancements for impregnated materials. However, DNP enhancements alone do not determine the overall sensitivity of a NMR experiment. Here we measure the overall sensitivity of one-dimensional 1H detected relayed DNP experiments as a function of the MAS rate in the 20-60 kHz regime using 0.7 mm diameter rotors at 21.2 T. Although faster MAS rates are detrimental for the DNP enhancement on the target material, due to slower spin diffusion, we find that with increasing spinning rates the gain in sensitivity due to 1H line-narrowing and the folding-in of sideband intensity compensates a large part of the loss of overall hyperpolarization. We find that sensitivity depends on the atomic site in the molecule, and is maximised at between 40 and 50 kHz MAS for the sample of L-histidine.HCl·H2O studied here. There is a 10-20 % difference in sensitivity between the optimum MAS rate and the fastest rate currently accessible (60 kHz).
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Affiliation(s)
- Saumya Badoni
- Institut des Sciences et Ingénierie Chimiques, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Pierrick Berruyer
- Institut des Sciences et Ingénierie Chimiques, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Lyndon Emsley
- Institut des Sciences et Ingénierie Chimiques, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland.
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3
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Halder A, Bain DC, Pitt TA, Shi Z, Oktawiec J, Lee JH, Tsangari S, Ng M, Fuentes-Rivera JJ, Forse AC, Runčevski T, Muller DA, Musser AJ, Milner PJ. Kinetic Trapping of Photoluminescent Frameworks During High-Concentration Synthesis of Non-Emissive Metal-Organic Frameworks. CHEMISTRY OF MATERIALS : A PUBLICATION OF THE AMERICAN CHEMICAL SOCIETY 2023; 35:10086-10098. [PMID: 38225948 PMCID: PMC10788154 DOI: 10.1021/acs.chemmater.3c02121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/17/2024]
Abstract
Metal-organic frameworks (MOFs) are porous, crystalline materials constructed from organic linkers and inorganic nodes with potential utility in gas separations, drug delivery, sensing, and catalysis. Small variations in MOF synthesis conditions can lead to a range of accessible frameworks with divergent chemical or photophysical properties. New methods to controllably access phases with tailored properties would broaden the scope of MOFs that can be reliably prepared for specific applications. Herein, we demonstrate that simply increasing the reaction concentration during the solvothermal synthesis of M2(dobdc) (M = Mg, Mn, Ni; dobdc4- = 2,5-dioxido-1,4-benzenedicarboxylate) MOFs unexpectedly leads to trapping of a new framework termed CORN-MOF-1 (CORN = Cornell University) instead. In-depth spectroscopic, crystallographic, and computational studies support that CORN-MOF-1 has a similar structure to M2(dobdc) but with partially protonated linkers and charge-balancing or coordinated formate groups in the pores. The resultant variation in linker spacings causes CORN-MOF-1 (Mg) to be strongly photoluminescent in the solid state, whereas H4dobdc and Mg2(dobdc) are weakly emissive due to excimer formation. In-depth photophysical studies suggest that CORN-MOF-1 (Mg) is the first MOF based on the H2dobdc2- linker that likely does not emit via an excited state intramolecular proton transfer (ESIPT) pathway. In addition, CORN-MOF-1 variants can be converted into high-quality samples of the thermodynamic M2(dobdc) phases by heating in N,N-dimethylformamide (DMF). Overall, our findings support that high-concentration synthesis provides a straightforward method to identify new MOFs with properties distinct from known materials and to produce highly porous samples of MOFs, paving the way for the discovery and gram-scale synthesis of framework materials.
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Affiliation(s)
- Arjun Halder
- Department of Chemistry and Chemical Biology Cornell University, Ithaca, NY, 14850, United States
| | - David C. Bain
- Department of Chemistry and Chemical Biology Cornell University, Ithaca, NY, 14850, United States
| | - Tristan A. Pitt
- Department of Chemistry and Chemical Biology Cornell University, Ithaca, NY, 14850, United States
| | - Zixiao Shi
- Department of Applied Engineering Physics, Cornell University, Ithaca, NY, 14850, United States
| | - Julia Oktawiec
- Department of Chemistry, Northwestern University, Evanston, IL, 60208, United States
| | - Jung-Hoon Lee
- Computational Science Research Center, Korea Institute of Science and Technology, Seoul, 02792, Republic of Korea
| | - Stavrini Tsangari
- Department of Chemistry and Chemical Biology Cornell University, Ithaca, NY, 14850, United States
| | - Marcus Ng
- Department of Chemistry and Chemical Biology Cornell University, Ithaca, NY, 14850, United States
| | - José J. Fuentes-Rivera
- Department of Chemistry and Chemical Biology Cornell University, Ithaca, NY, 14850, United States
| | - Alexander C. Forse
- Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, United Kingdom
| | - Tomče Runčevski
- Department of Chemistry, Southern Methodist University, Dallas, TX, 75275, United States
| | - David A. Muller
- Department of Applied Engineering Physics, Cornell University, Ithaca, NY, 14850, United States
| | - Andrew J. Musser
- Department of Chemistry and Chemical Biology Cornell University, Ithaca, NY, 14850, United States
| | - Phillip J. Milner
- Department of Chemistry and Chemical Biology Cornell University, Ithaca, NY, 14850, United States
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4
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Biswas R, Chen Y, Vela J, Rossini AJ. Relativistic DFT Calculations of Cadmium and Selenium Solid-State NMR Spectra of CdSe Nanocrystal Surfaces. ACS OMEGA 2023; 8:44362-44371. [PMID: 38027327 PMCID: PMC10666156 DOI: 10.1021/acsomega.3c07680] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/03/2023] [Revised: 10/11/2023] [Accepted: 10/16/2023] [Indexed: 12/01/2023]
Abstract
Solid-state NMR spectra have been used to probe the structure of CdSe nanocrystals and propose detailed models of their surface structures. Density functional theory (DFT)-optimized cluster models that represent probable molecular structures of carboxylate-coordinated surface sites have been proposed. However, to the best of our knowledge, 113Cd and 77Se chemical shifts have not been calculated for these surface models. We performed relativistic DFT calculations of cadmium and selenium magnetic shielding tensors on model compounds with previously measured solid-state NMR spectra with (i) the four-component Dirac-Kohn-Sham (DKS) Hamiltonian and (ii) the scalar and (iii) spin-orbit levels within the ZORA Hamiltonian. Molecular clusters with Cd and Se sites in varying bonding environments were used to model CdSe (100) and CdSe(111) surfaces capped with carboxylic acid ligands. Our calculations identify the observed 113Cd isotropic chemical shifts δ(iso) of -465, -318, and -146 ppm arising from CdSeO3, CdSe2O2, and CdSe3O surface groups, respectively, with very good agreement with experimental measurements. The 113Cd chemical shifts linearly decrease with the number of O-neighbors. The calculated spans (δ11 - δ33) encompass the experimental values for CdSe3O and CdSe2O2 clusters but are slightly larger than the measured value for CdSeO3 clusters. Relativistic DFT calculations predicted a one-bond 113Cd-77Se scalar coupling of 258 Hz, which is in good agreement with the experimental values of 250 Hz. With a dense coverage of carboxylic acid ligands, the CdSe (100) surface shows a distribution of Cd-Se bond lengths and J-couplings. Relativistic DFT simulations thus aid in interpretation of NMR spectra of CdSe nanocrystals and related nanomaterials.
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Affiliation(s)
- Rana Biswas
- U.S.
Department of Energy Ames National Laboratory, Ames, Iowa 50011. United States
- Department
of Physics and Astronomy; Electrical & Computer Engineering; Microelectronics
Research Center, Iowa State University, Ames, Iowa 50011. United States
| | - Yunhua Chen
- U.S.
Department of Energy Ames National Laboratory, Ames, Iowa 50011. United States
- Department
of Chemistry, Iowa State University, Ames, Iowa 50011. United States
| | - Javier Vela
- U.S.
Department of Energy Ames National Laboratory, Ames, Iowa 50011. United States
- Department
of Chemistry, Iowa State University, Ames, Iowa 50011. United States
| | - Aaron J. Rossini
- U.S.
Department of Energy Ames National Laboratory, Ames, Iowa 50011. United States
- Department
of Chemistry, Iowa State University, Ames, Iowa 50011. United States
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5
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Simões de Almeida B, Torodii D, Moutzouri P, Emsley L. Barriers to resolution in 1H NMR of rotating solids. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2023; 355:107557. [PMID: 37776831 DOI: 10.1016/j.jmr.2023.107557] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Revised: 09/14/2023] [Accepted: 09/15/2023] [Indexed: 10/02/2023]
Abstract
The role of 1H solid-state NMR in structure elucidation of solids is becoming more preponderant, particularly as faster magic-angle spinning rates (MAS) become available which improve 1H detected assignment strategies. However, current 1H spectral resolution is still relatively poor, with linewidths of typically a few hundred Hz, even at the fastest rates available today. Here we detail and assess the factors limiting proton linewidths and line shapes in MAS experiments with five different samples, exemplifying the different sources of broadening that affect the residual linewidth. We disentangle the different contributions through one- and two-dimensional experiments: by using dilution to identify the contribution of ABMS; by using extensive deuteration to identify the dipolar contributions; and by using variable MAS rates to determine the ratio between homogeneous and inhomogeneous components. We find that the overall widths and the nature of the different contributions to the linewidths can vary very considerably. While we find that faster spinning always yields narrower lines and longer coherence lifetimes, we also find that for some resonances the dipolar contribution is no longer dominant at 100 kHz MAS. When the inhomogeneous sources of broadening, such as ABMS and chemical shift disorder, are dominant, two-dimensional 1H-1H correlation experiments yield better resolution for assignment. Particularly the extraction of the antidiagonal of a 2D peak will remove any correlated inhomogeneous broadening, giving substantially narrower 1H linewidths.
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Affiliation(s)
- Bruno Simões de Almeida
- Institut des Sciences et Ingénierie Chimiques, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015, Lausanne, Switzerland
| | - Daria Torodii
- Institut des Sciences et Ingénierie Chimiques, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015, Lausanne, Switzerland
| | - Pinelopi Moutzouri
- Institut des Sciences et Ingénierie Chimiques, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015, Lausanne, Switzerland
| | - Lyndon Emsley
- Institut des Sciences et Ingénierie Chimiques, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015, Lausanne, Switzerland.
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6
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Bartalucci E, Malär AA, Mehnert A, Kleine Büning JB, Günzel L, Icker M, Börner M, Wiebeler C, Meier BH, Grimme S, Kersting B, Wiegand T. Probing a Hydrogen-π Interaction Involving a Trapped Water Molecule in the Solid State. Angew Chem Int Ed Engl 2023; 62:e202217725. [PMID: 36630178 DOI: 10.1002/anie.202217725] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2022] [Revised: 01/11/2023] [Accepted: 01/11/2023] [Indexed: 01/12/2023]
Abstract
The detection and characterization of trapped water molecules in chemical entities and biomacromolecules remains a challenging task for solid materials. We herein present proton-detected solid-state Nuclear Magnetic Resonance (NMR) experiments at 100 kHz magic-angle spinning and at high static magnetic-field strengths (28.2 T) enabling the detection of a single water molecule fixed in the calix[4]arene cavity of a lanthanide complex by a combination of three types of non-covalent interactions. The water proton resonances are detected at a chemical-shift value close to zero ppm, which we further confirm by quantum-chemical calculations. Density Functional Theory calculations pinpoint to the sensitivity of the proton chemical-shift value for hydrogen-π interactions. Our study highlights how proton-detected solid-state NMR is turning into the method-of-choice in probing weak non-covalent interactions driving a whole branch of molecular-recognition events in chemistry and biology.
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Affiliation(s)
- Ettore Bartalucci
- Max-Planck-Institute for Chemical Energy Conversion, Stiftstr. 34-36, 45470, Mülheim an der Ruhr, Germany.,Institute of Technical and Macromolecular Chemistry, RWTH Aachen University, Worringerweg 2, 52074, Aachen, Germany
| | | | - Anne Mehnert
- Institute of Inorganic Chemistry, Leipzig University, Johannisallee 29, 04103, Leipzig, Germany
| | - Julius B Kleine Büning
- Mulliken Center for Theoretical Chemistry, Clausius Institute of Physical and Theoretical Chemistry, University of Bonn, Beringstraße 4, 53115, Bonn, Germany
| | - Lennart Günzel
- Institute of Inorganic Chemistry, Leipzig University, Johannisallee 29, 04103, Leipzig, Germany
| | - Maik Icker
- Institute of Organic Chemistry, Leipzig University Linnéstraße 3, 04103, Leipzig, Germany
| | - Martin Börner
- Institute of Inorganic Chemistry, Leipzig University, Johannisallee 29, 04103, Leipzig, Germany
| | - Christian Wiebeler
- Institute of Analytic Chemistry, Leipzig University, Linnéstraße 3, 04103, Leipzig, Germany.,Wilhelm-Ostwald-Institute for Physical and Theoretical Chemistry, Leipzig University, Linnéstraße 2, 04103, Leipzig, Germany
| | - Beat H Meier
- Physical Chemistry, ETH Zurich, 8093, Zurich, Switzerland
| | - Stefan Grimme
- Mulliken Center for Theoretical Chemistry, Clausius Institute of Physical and Theoretical Chemistry, University of Bonn, Beringstraße 4, 53115, Bonn, Germany
| | - Berthold Kersting
- Institute of Inorganic Chemistry, Leipzig University, Johannisallee 29, 04103, Leipzig, Germany
| | - Thomas Wiegand
- Max-Planck-Institute for Chemical Energy Conversion, Stiftstr. 34-36, 45470, Mülheim an der Ruhr, Germany.,Institute of Technical and Macromolecular Chemistry, RWTH Aachen University, Worringerweg 2, 52074, Aachen, Germany.,previous address: Physical Chemistry, ETH Zurich, 8093, Zurich, Switzerland
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7
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Blahut J, Štoček JR, Šála M, Dračínský M. The hydrogen bond continuum in solid isonicotinic acid. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2022; 345:107334. [PMID: 36410062 DOI: 10.1016/j.jmr.2022.107334] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Revised: 11/03/2022] [Accepted: 11/07/2022] [Indexed: 06/16/2023]
Abstract
The understanding and correct description of intermolecular hydrogen bonds are crucial in the field of multicomponent pharmaceutical solids, such as salts and cocrystals. Solid isonicotinic acid can serve as a suitable model for the development of methods that can accurately characterize these hydrogen bonds. Experimental solid-state NMR has revealed a remarkable temperature dependence and deuterium-isotope-induced changes of the chemical shifts of the atoms involved in the intermolecular hydrogen bond; these NMR data are related to changes of the average position of the hydrogen atom. These changes of NMR parameters were interpreted using periodic DFT path-integral molecular dynamics (PIMD) simulations. The small size of the unit cell of isonicotinic acid allowed for PIMD simulations with the computationally demanding hybrid DFT functional. Calculations of NMR parameters based on the hybrid-functional PIMD simulations are in excellent agreement with experiment. It is thus demonstrated that an accurate characterization of intermolecular hydrogen bonds can be achieved by a combination of NMR experiments and advanced computations.
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Affiliation(s)
- Jan Blahut
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Flemingovo nám. 2, 160 00 Prague 6, Czech Republic
| | - Jakub Radek Štoček
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Flemingovo nám. 2, 160 00 Prague 6, Czech Republic; Department of Organic Chemistry, Faculty of Science, Charles University in Prague, 128 40 Prague 2, Czech Republic
| | - Michal Šála
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Flemingovo nám. 2, 160 00 Prague 6, Czech Republic
| | - Martin Dračínský
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Flemingovo nám. 2, 160 00 Prague 6, Czech Republic.
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8
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Carnahan SL, Chen Y, Wishart JF, Lubach JW, Rossini AJ. Magic angle spinning dynamic nuclear polarization solid-state NMR spectroscopy of γ-irradiated molecular organic solids. SOLID STATE NUCLEAR MAGNETIC RESONANCE 2022; 119:101785. [PMID: 35405629 DOI: 10.1016/j.ssnmr.2022.101785] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2021] [Revised: 02/22/2022] [Accepted: 03/04/2022] [Indexed: 06/14/2023]
Abstract
In the past 15 years, magic angle spinning (MAS) dynamic nuclear polarization (DNP) has emerged as a method to increase the sensitivity of high-resolution solid-state NMR spectroscopy experiments. Recently, γ-irradiation has been used to generate significant concentrations of homogeneously distributed free radicals in a variety of solids, including quartz, glucose, and cellulose. Both γ-irradiated quartz and glucose previously showed significant MAS DNP enhancements. Here, γ-irradiation is applied to twelve small organic molecules to test the applicability of γ-irradiation as a general method of creating stable free radicals for MAS DNP experiments on organic solids and pharmaceuticals. Radical concentrations in the range of 0.25 mM-10 mM were observed in irradiated glucose, histidine, malic acid, and malonic acid, and significant 1H DNP enhancements of 32, 130, 19, and 11 were obtained, respectively, as measured by 1H→13C CPMAS experiments. However, concentrations of free radicals below 0.05 mM were generally observed in organic molecules containing aromatic rings, preventing sizeable DNP enhancements. DNP sensitivity gains for several of the irradiated compounds exceed that which can be obtained with the relayed DNP approach that uses exogeneous polarizing agent solutions and impregnation procedures. In several cases, significant 1H DNP enhancements were realized at room temperature. This study demonstrates that in many cases γ-irradiation is a viable alternative to addition of stable exogenous radicals for DNP experiments on organic solids.
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Affiliation(s)
- Scott L Carnahan
- US DOE Ames Laboratory, Ames, IA, 50011, USA; Iowa State University, Department of Chemistry, Ames, IA, 50011, USA
| | - Yunhua Chen
- US DOE Ames Laboratory, Ames, IA, 50011, USA; Iowa State University, Department of Chemistry, Ames, IA, 50011, USA
| | - James F Wishart
- Brookhaven National Laboratory, Chemistry Division, Upton, NY, 11973, United States
| | - Joseph W Lubach
- Genentech Inc., South San Francisco, CA, 94080, United States
| | - Aaron J Rossini
- US DOE Ames Laboratory, Ames, IA, 50011, USA; Iowa State University, Department of Chemistry, Ames, IA, 50011, USA.
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9
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Yuan EC, Chen P, Huang S, Org M, Samoson A, Chan JCC. Solid‐state heteronuclear multiple‐quantum spectroscopy under a magic‐angle spinning frequency of 150
kHz. J CHIN CHEM SOC-TAIP 2022. [DOI: 10.1002/jccs.202200063] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
| | - Po‐Wen Chen
- Department of Chemistry National Taiwan University Taipei Republic of China
| | - Shing‐Jong Huang
- Instrumentation Center National Taiwan University Taipei Republic of China
| | - Mai‐Liis Org
- Institute of Health Technologies Tallinn University of Technology Tallinn Estonia
| | - Ago Samoson
- Institute of Health Technologies Tallinn University of Technology Tallinn Estonia
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10
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Fu ZZ, Guo SJ, Li CX, Wang K, Zhang Q, Fu Q. Hydrogen-bond-dominated mechanical stretchability in PVA films: from phenomenological to numerical insights. Phys Chem Chem Phys 2022; 24:1885-1895. [PMID: 34990505 DOI: 10.1039/d1cp03893a] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Hydrogen bonds (H-bonds) in poly(vinyl alcohol) (PVA) play a crucial role in macroscopic mechanical properties, particularly for stretchability. However, there is still some ambiguity about the quantitative dependence of H-bond interactions on the mechanical performance, mainly attributed to the difficulty in the discrimination of various H-bond types. Herein, small molecular chemicals as plasticizers were incorporated into the PVA matrix to tailor the H-bonding interactions. By altering the PVA molecular weight, plasticizer type and loading, both the stretchability and H-bond content were regulated on a large scale. By a combination of DMA, IR spectroscopy, MD simulation and solid-state 13C-NMR, every sort of H-bond in PVA was assigned, and their relative fractions were ascertained quantitatively. After correlating the elongation ratio with the relative fraction of the different types of H-bonding interaction, it was found that all the pairs of elongation vs. intermolecular H-bond content derived from different series of PVA/plasticizer films could be plotted into a master curve and exhibited good linearity, indicating that intermolecular H-bonds dominate the mechanical stretchability in PVA films. Our efforts contribute towards an in-depth understanding of performance optimization induced by H-bond manipulation from empirical, phenomenological aspects to intrinsic, numerical insights.
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Affiliation(s)
- Zhen-Zhen Fu
- College of Polymer Science and Engineering, Sichuan University, State Key Laboratory of Polymer Materials Engineering, Chengdu 610065, People's Republic of China.
| | - Sheng-Jie Guo
- College of Polymer Science and Engineering, Sichuan University, State Key Laboratory of Polymer Materials Engineering, Chengdu 610065, People's Republic of China.
| | - Chen-Xi Li
- College of Polymer Science and Engineering, Sichuan University, State Key Laboratory of Polymer Materials Engineering, Chengdu 610065, People's Republic of China.
| | - Ke Wang
- College of Polymer Science and Engineering, Sichuan University, State Key Laboratory of Polymer Materials Engineering, Chengdu 610065, People's Republic of China.
| | - Qin Zhang
- College of Polymer Science and Engineering, Sichuan University, State Key Laboratory of Polymer Materials Engineering, Chengdu 610065, People's Republic of China.
| | - Qiang Fu
- College of Polymer Science and Engineering, Sichuan University, State Key Laboratory of Polymer Materials Engineering, Chengdu 610065, People's Republic of China.
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11
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Malär AA, Sun Q, Zehnder J, Kehr G, Erker G, Wiegand T. Proton-phosphorous connectivities revealed by high-resolution proton-detected solid-state NMR. Phys Chem Chem Phys 2022; 24:7768-7778. [DOI: 10.1039/d2cp00616b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Proton-detected solid-state NMR enables atomic-level insight in solid-state reactions, for instance in heterogeneous catalysis, which is fundamental for deciphering chemical reaction mechanisms. We herein introduce a phosphorus-31 radiofrequency channel in...
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12
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Lee S, Viswanathan G, Carnahan S, Harmer C, Akopov G, Rossini A, Miller G, Kovnir K. Add a Pinch of Tetrel: The Transformation of a Centrosymmetric Metal into a Nonsymmorphic and Chiral Semiconductor. Chemistry 2021; 28:e202104319. [PMID: 34882857 PMCID: PMC9302624 DOI: 10.1002/chem.202104319] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Indexed: 11/21/2022]
Abstract
Centrosymmetric skutterudite RhP3 was converted to a nonsymmorphic and chiral compound RhSi0.3P2.7 (space group P212121) by means of partial replacement of Si for P. The structure, determined by a combination of X‐ray crystallography and solid state 31P NMR, exhibits branched polyanionic P/Si chains that are unique among metal phosphides. A driving force to stabilize the locally noncentrosymmetric cis‐RhSi2P4 and fac‐RhSi3P3 fragments is π‐electron back‐donation between the Rh t2g‐type orbitals and the unoccupied antibonding Si/P orbitals, which is more effective for Si than for P. In situ studies and total energy calculations revealed the metastable nature of RhSi0.3P2.7. Electronic structure calculations predicted centrosymmetric cubic RhP3 to be metallic which was confirmed by transport properties measurements. In contrast, the electronic structure for chiral orthorhombic RhSi0.3P2.7 contained a bandgap, and this compound was shown to be a narrow gap semiconductor.
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Affiliation(s)
- Shannon Lee
- Iowa State University of Science and Technology: Iowa State University, Chemistry, UNITED STATES
| | - Gayatri Viswanathan
- Iowa State University of Science and Technology: Iowa State University, Chemistry, UNITED STATES
| | - Scott Carnahan
- Iowa State University of Science and Technology: Iowa State University, Chemistry, UNITED STATES
| | - Colin Harmer
- Iowa State University of Science and Technology: Iowa State University, Chemistry, UNITED STATES
| | | | - Aaron Rossini
- Iowa State University of Science and Technology: Iowa State University, Chemistry, UNITED STATES
| | - Gordon Miller
- Iowa State University of Science and Technology: Iowa State University, Chemistry, UNITED STATES
| | - Kirill Kovnir
- Iowa State University, Department of Chemistry, 2415 Osborn Drive, 50011, Ames, UNITED STATES
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Muresan-Pop M, Vulpoi A, Simon V, Todea M, Magyari K, Pap Z, Simion A, Filip C, Simon S. Co-Crystals of Etravirine by Mechanochemical Activation. J Pharm Sci 2021; 111:1178-1186. [PMID: 34562446 DOI: 10.1016/j.xphs.2021.09.023] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2021] [Revised: 09/17/2021] [Accepted: 09/17/2021] [Indexed: 11/16/2022]
Abstract
The co-crystals formation of etravirine with three carboxylic acids was investigated. New co-crystals of etravirine with adipic acid, benzoic acid, and 4-hydroxybenzoic acid have been synthesized by wet milling of ingredients for 120 min. The novelty of these solid forms was first evidenced by powder X-ray diffraction. Their different morphology was evidenced by SEM microscopy. Spectroscopic analyses (FT-IR, MAS-NMR, and XPS) highlighted the hydrogen bonds between etravirine and co-formers, as a result of the solid-state reaction of the ingredients by wet milling. Thermal analyses pointed out that the milling process caused in co-crystals a reduction in the fusion enthalpy and the melting temperature, compared to the values obtained for etravirine. These co-crystals are stable up to four months on storage under extreme conditions, excepting the co-crystal with benzoic acid which begins to transform into a polymorph of etravirine after 30 days. The UV absorption spectra of the samples tested in three simulated physiological media with pH values of 6, 6.3, and 7 have evidenced the conformation change of etravirine due to hydrogen bonds between etravirine and carboxylic acids.
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Affiliation(s)
- Marieta Muresan-Pop
- Interdisciplinary Research Institute on Bio-Nano-Sciences, Center of Nanostructured Materials and Bio-Nano Interfaces, Babes-Bolyai University, 400271 Cluj-Napoca, Romania.
| | - Adriana Vulpoi
- Interdisciplinary Research Institute on Bio-Nano-Sciences, Center of Nanostructured Materials and Bio-Nano Interfaces, Babes-Bolyai University, 400271 Cluj-Napoca, Romania
| | - Viorica Simon
- Interdisciplinary Research Institute on Bio-Nano-Sciences, Center of Nanostructured Materials and Bio-Nano Interfaces, Babes-Bolyai University, 400271 Cluj-Napoca, Romania; Faculty of Physics, Babes-Bolyai University, 400084 Cluj-Napoca, Romania
| | - Milica Todea
- Interdisciplinary Research Institute on Bio-Nano-Sciences, Center of Nanostructured Materials and Bio-Nano Interfaces, Babes-Bolyai University, 400271 Cluj-Napoca, Romania; Department of Molecular Sciences, Iuliu Hatieganu University of Medicine and Pharmacy, 400012 Cluj-Napoca, Romania
| | - Klara Magyari
- Interdisciplinary Research Institute on Bio-Nano-Sciences, Center of Nanostructured Materials and Bio-Nano Interfaces, Babes-Bolyai University, 400271 Cluj-Napoca, Romania; Department of Applied and Environmental Sciences, University of Szeged, 6720 Szeged, Hungary
| | - Zsolt Pap
- Interdisciplinary Research Institute on Bio-Nano-Sciences, Center of Nanostructured Materials and Bio-Nano Interfaces, Babes-Bolyai University, 400271 Cluj-Napoca, Romania; Department of Applied and Environmental Sciences, University of Szeged, 6720 Szeged, Hungary
| | - Andrea Simion
- Faculty of Physics, Babes-Bolyai University, 400084 Cluj-Napoca, Romania
| | - Claudiu Filip
- National Institute for Research and Development of Isotopic and Molecular Technologies, 400293 Cluj-Napoca, Romania
| | - Simion Simon
- Interdisciplinary Research Institute on Bio-Nano-Sciences, Center of Nanostructured Materials and Bio-Nano Interfaces, Babes-Bolyai University, 400271 Cluj-Napoca, Romania; Faculty of Physics, Babes-Bolyai University, 400084 Cluj-Napoca, Romania
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14
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Yuan ECY, Huang SJ, Huang HC, Sinkkonen J, Oss A, Org ML, Samoson A, Tai HC, Chan JCC. Faster magic angle spinning reveals cellulose conformations in woods. Chem Commun (Camb) 2021; 57:4110-4113. [PMID: 33908496 DOI: 10.1039/d1cc01149a] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We present a first report on the detection of three different C6 conformers of cellulose in spruce, as revealed by solid-state 1H-13C correlation spectra. The breakthrough in 1H resolution is achieved by magic-angle spinning in the regime of 150 kHz. The suppression of dense dipolar network of 1H provides inverse detected 13C spectra at a good sensitivity even in natural samples. We find that the glycosidic linkages are initially more ordered in spruce than maple, but a thermal treatment of spruce leads to a more heterogeneous packing order of the remaining cellulose fibrils.
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Affiliation(s)
- Eric Chung-Yueh Yuan
- Department of Chemistry, National Taiwan University, Taipei 10617, Taiwan, Republic of China.
| | - Shing-Jong Huang
- Instrumentation Center, National Taiwan University, Taipei 10617, Taiwan, Republic of China
| | - Hung-Chia Huang
- Department of Chemistry, National Taiwan University, Taipei 10617, Taiwan, Republic of China.
| | - Jari Sinkkonen
- Innovation Centre for Biomaterials, Stora Enso AB, Nacka 13154, Sweden
| | - Andres Oss
- Tallinn University of Technology, Estonia.
| | | | | | - Hwan-Ching Tai
- Department of Chemistry, National Taiwan University, Taipei 10617, Taiwan, Republic of China.
| | - Jerry Chun Chung Chan
- Department of Chemistry, National Taiwan University, Taipei 10617, Taiwan, Republic of China.
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15
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Jiang S, Zeng Z, Xue W, Zhang W, Zhou Z. Kinetic study on the reaction of palmitic acid with ethanol catalyzed by deep eutectic solvent based on dodecyl trimethyl ammonium chloride. KOREAN J CHEM ENG 2020. [DOI: 10.1007/s11814-020-0557-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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16
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A Practical Review of NMR Lineshapes for Spin-1/2 and Quadrupolar Nuclei in Disordered Materials. Int J Mol Sci 2020; 21:ijms21165666. [PMID: 32784642 PMCID: PMC7461203 DOI: 10.3390/ijms21165666] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Revised: 07/31/2020] [Accepted: 08/05/2020] [Indexed: 01/06/2023] Open
Abstract
NMR is a powerful spectroscopic method that can provide information on the structural disorder in solids, complementing scattering and diffraction techniques. The structural disorder in solids can generate a dispersion of local magnetic and electric fields, resulting in a distribution of isotropic chemical shift δiso and quadrupolar coupling CQ. For spin-1/2 nuclei, the NMR linewidth and shape under high-resolution magic-angle spinning (MAS) reflects the distributions of isotropic chemical shift, providing a rich source of disorder information. For quadrupolar nuclei, the second-order quadrupolar broadening remains present even under MAS. In addition to isotropic chemical shift, structural disorder can impact the electric field gradient (EFG) and consequently the quadrupolar NMR parameters. The distributions of quadrupolar coupling and isotropic chemical shift are superimposed with the second-order quadrupolar broadening, but can be potentially characterized by MQMAS (multiple-quantum magic-angle spinning) spectroscopy. We review analyses of NMR lineshapes in 2D DQ–SQ (double-quantum single-quantum) and MQMAS spectroscopies, to provide a guide for more general lineshape analysis. In addition, methods to enhance the spectral resolution and sensitivity for quadrupolar nuclei are discussed, including NMR pulse techniques and the application of high magnetic fields. The role of magnetic field strength and its impact on the strategy of determining optimum NMR methods for disorder characterization are also discussed.
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17
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Rees GJ, Day SP, Barnsley KE, Iuga D, Yates JR, Wallis JD, Hanna JV. Measuring multiple 17O–13C J-couplings in naphthalaldehydic acid: a combined solid state NMR and density functional theory approach. Phys Chem Chem Phys 2020; 22:3400-3413. [DOI: 10.1039/c9cp03977e] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A combined multinuclear solid-state NMR and a density functional theory computational approach, with SIMPSON simulations, is evaluated to determine the four heteronuclear 1J(13C,17O) couplings in naphthalaldehydic acid.
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Affiliation(s)
| | | | | | - Dinu Iuga
- Department of Physics
- University of Warwick
- Coventry
- UK
| | | | - John D. Wallis
- School of Science and Technology
- Nottingham Trent University
- Nottingham
- UK
| | - John V. Hanna
- Department of Physics
- University of Warwick
- Coventry
- UK
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18
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Zhao L, Pinon AC, Emsley L, Rossini AJ. DNP-enhanced solid-state NMR spectroscopy of active pharmaceutical ingredients. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2018; 56:583-609. [PMID: 29193278 DOI: 10.1002/mrc.4688] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2017] [Revised: 11/15/2017] [Accepted: 11/19/2017] [Indexed: 06/07/2023]
Abstract
Solid-state NMR spectroscopy has become a valuable tool for the characterization of both pure and formulated active pharmaceutical ingredients (APIs). However, NMR generally suffers from poor sensitivity that often restricts NMR experiments to nuclei with favorable properties, concentrated samples, and acquisition of one-dimensional (1D) NMR spectra. Here, we review how dynamic nuclear polarization (DNP) can be applied to routinely enhance the sensitivity of solid-state NMR experiments by one to two orders of magnitude for both pure and formulated APIs. Sample preparation protocols for relayed DNP experiments and experiments on directly doped APIs are detailed. Numerical spin diffusion models illustrate the dependence of relayed DNP enhancements on the relaxation properties and particle size of the solids and can be used for particle size determination when the other factors are known. We then describe the advanced solid-state NMR experiments that have been enabled by DNP and how they provide unique insight into the molecular and macroscopic structure of APIs. For example, with large sensitivity gains provided by DNP, natural isotopic abundance, 13 C-13 C double-quantum single-quantum homonuclear correlation NMR spectra of pure APIs can be routinely acquired. DNP also enables solid-state NMR experiments with unreceptive quadrupolar nuclei such as 2 H, 14 N, and 35 Cl that are commonly found in APIs. Applications of DNP-enhanced solid-state NMR spectroscopy for the molecular level characterization of low API load formulations such as commercial tablets and amorphous solid dispersions are described. Future perspectives for DNP-enhanced solid-state NMR experiments on APIs are briefly discussed.
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Affiliation(s)
- Li Zhao
- Department of Chemistry, Iowa State University, Ames, IA, USA
- US DOE Ames Laboratory, Ames, IA, USA
| | - Arthur C Pinon
- Institut des Sciences et Ingénierie Chimiques, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015, Lausanne, Switzerland
| | - Lyndon Emsley
- Institut des Sciences et Ingénierie Chimiques, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015, Lausanne, Switzerland
| | - Aaron J Rossini
- Department of Chemistry, Iowa State University, Ames, IA, USA
- US DOE Ames Laboratory, Ames, IA, USA
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19
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Zhang Y, Lucier BEG, Fischer M, Gan Z, Boyle PD, Desveaux B, Huang Y. A Multifaceted Study of Methane Adsorption in Metal-Organic Frameworks by Using Three Complementary Techniques. Chemistry 2018; 24:7866-7881. [PMID: 29575184 DOI: 10.1002/chem.201800424] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2018] [Revised: 03/17/2018] [Indexed: 12/31/2022]
Abstract
Methane is a promising clean and inexpensive energy alternative to traditional fossil fuels, however, its low volumetric energy density at ambient conditions has made devising viable, efficient methane storage systems very challenging. Metal-organic frameworks (MOFs) are promising candidates for methane storage. In order to improve the methane storage capacity of MOFs, a better understanding of the methane adsorption, mobility, and host-guest interactions within MOFs must be realized. In this study, methane adsorption within α-Mg3 (HCO2 )6 , α-Zn3 (HCO2 )6 , SIFSIX-3-Zn, and M-MOF-74 (M=Mg, Zn, Ni, Co) has been comprehensively examined. Single-crystal X-ray diffraction (SCXRD) experiments and DFT calculations of the methane adsorption locations were performed for α-Mg3 (HCO2 )6 , α-Zn3 (HCO2 )6 , and SIFSIX-3-Zn. The SCXRD thermal ellipsoids indicate that methane possesses significant mobility at the adsorption sites in each system. 2 H solid-state NMR (SSNMR) experiments targeting deuterated CH3 D guests in α-Mg3 (HCO2 )6 , α-Zn3 (HCO2 )6 , SIFSIX-3-Zn, and MOF-74 yield an interesting finding: the 2 H SSNMR spectra of methane adsorbed in these MOFs are significantly influenced by the chemical shielding anisotropy in addition to the quadrupolar interaction. The chemical shielding anisotropy contribution is likely due mainly to the nuclear independent chemical shift effect on the MOF surfaces. In addition, the 2 H SSNMR results and DFT calculations strongly indicate that the methane adsorption strength is linked to the MOF pore size and that dispersive forces are responsible for the methane adsorption in these systems. This work lays a very promising foundation for future studies of methane adsorption locations and dynamics within adsorbent MOF materials.
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Affiliation(s)
- Yue Zhang
- Department of Chemistry, The University of Western Ontario, 1151 Richmond Street, London, Ontario, N6A 5B7, Canada
| | - Bryan E G Lucier
- Department of Chemistry, The University of Western Ontario, 1151 Richmond Street, London, Ontario, N6A 5B7, Canada
| | - Michael Fischer
- Crystallography group, Department of Geosciences, University of Bremen, Klagenfurter Straße 2-4, D-28359, Bremen, Germany
- MAPEX Center for Materials and Processes, University of Bremen, D-28359, Bremen, Germany
| | - Zhehong Gan
- Centre of Interdisciplinary Magnetic Resonance, National High Magnetic Field Laboratory, 1800 East Paul Dirac Drive, Tallahassee, FL, 32310, USA
| | - Paul D Boyle
- Department of Chemistry, The University of Western Ontario, 1151 Richmond Street, London, Ontario, N6A 5B7, Canada
| | - Bligh Desveaux
- Department of Chemistry, The University of Western Ontario, 1151 Richmond Street, London, Ontario, N6A 5B7, Canada
| | - Yining Huang
- Department of Chemistry, The University of Western Ontario, 1151 Richmond Street, London, Ontario, N6A 5B7, Canada
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20
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Blaakmeer ES, Antinucci G, Correa A, Busico V, van Eck ERH, Kentgens APM. Structural Characterization of Electron Donors in Ziegler-Natta Catalysts. THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2018; 122:5525-5536. [PMID: 29568341 PMCID: PMC5857925 DOI: 10.1021/acs.jpcc.7b12667] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/24/2017] [Revised: 02/13/2018] [Indexed: 06/08/2023]
Abstract
Ziegler-Natta catalysis is a very important industrial process for the production of polyolefins. However, the catalysts are not well-understood at the molecular level. Yet, atomic-scale structural information is of pivotal importance for rational catalyst development. We applied a solid-state NMR/density functional theory tandem approach to gain detailed insight into the interactions between the catalysts' support, MgCl2, and organic electron donors. Because of the heterogeneity of the samples, large line widths are observed in the carbon spectra. Despite this, good agreement between experimental and computational values was reached, and this shows that 1,3-diether based donors coordinate at (110) surface sites, while phthalates are less selective and coordinate at both (104) and (110) surface sites.
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Affiliation(s)
- E. S.
Merijn Blaakmeer
- Institute
for Molecules and Materials, Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
- Dutch
Polymer Institute (DPI), P.O. Box 902, 5600 AX Eindhoven, The Netherlands
| | - Giuseppe Antinucci
- Dutch
Polymer Institute (DPI), P.O. Box 902, 5600 AX Eindhoven, The Netherlands
- Laboratory
of Stereoselective Polymerizations, Federico
II University of Naples, Via Cintia, 80126 Naples, Italy
| | - Andrea Correa
- Dutch
Polymer Institute (DPI), P.O. Box 902, 5600 AX Eindhoven, The Netherlands
- Laboratory
of Stereoselective Polymerizations, Federico
II University of Naples, Via Cintia, 80126 Naples, Italy
| | - Vincenzo Busico
- Dutch
Polymer Institute (DPI), P.O. Box 902, 5600 AX Eindhoven, The Netherlands
- Laboratory
of Stereoselective Polymerizations, Federico
II University of Naples, Via Cintia, 80126 Naples, Italy
| | - Ernst R. H. van Eck
- Institute
for Molecules and Materials, Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
| | - Arno P. M. Kentgens
- Institute
for Molecules and Materials, Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
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21
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Haser A, Cao T, Lubach JW, Zhang F. In Situ Salt Formation during Melt Extrusion for Improved Chemical Stability and Dissolution Performance of a Meloxicam–Copovidone Amorphous Solid Dispersion. Mol Pharm 2018; 15:1226-1237. [DOI: 10.1021/acs.molpharmaceut.7b01057] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- Abbe Haser
- Division of Pharmaceutics, College of Pharmacy, The University of Texas at Austin, 2409 University Avenue, A1920, Austin, Texas 78712, United States
| | - Tu Cao
- Division of Pharmaceutics, College of Pharmacy, The University of Texas at Austin, 2409 University Avenue, A1920, Austin, Texas 78712, United States
| | - Joseph W. Lubach
- Genentech, 1 DNA Way, South San Francisco, California 94080, United States
| | - Feng Zhang
- Division of Pharmaceutics, College of Pharmacy, The University of Texas at Austin, 2409 University Avenue, A1920, Austin, Texas 78712, United States
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