1
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Rehman Z, Franks WT, Nguyen B, Schmidt HF, Scrivens G, Brown SP. Discovering the Solid-State Secrets of Lorlatinib by NMR Crystallography: To Hydrogen Bond or not to Hydrogen Bond. J Pharm Sci 2023; 112:1915-1928. [PMID: 36868358 DOI: 10.1016/j.xphs.2023.02.022] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Revised: 02/22/2023] [Accepted: 02/22/2023] [Indexed: 03/05/2023]
Abstract
Lorlatinib is an active pharmaceutical ingredient (API) used in the treatment of lung cancer. Here, an NMR crystallography analysis is presented whereby the single-crystal X-ray diffraction structure (CSD: 2205098) determination is complemented by multinuclear (1H, 13C, 14/15N, 19F) magic-angle spinning (MAS) solid-state NMR and gauge-including projector augmented wave (GIPAW) calculation of NMR chemical shifts. Lorlatinib crystallises in the P21 space group, with two distinct molecules in the asymmetric unit cell, Z' = 2. Three of the four NH2 hydrogen atoms form intermolecular hydrogen bonds, N30-H…N15 between the two distinct molecules and N30-H…O2 between two equivalent molecules. This is reflected in one of the NH21H chemical shifts being significantly lower, 4.0 ppm compared to 7.0 ppm. Two-dimensional 1H-13C, 14N-1H and 1H (double-quantum, DQ)-1H (single-quantum, SQ) MAS NMR spectra are presented. The 1H resonances are assigned and specific HH proximities corresponding to the observed DQ peaks are identified. The resolution enhancement at a 1H Larmor frequency of 1 GHz as compared to 500 or 600 MHz is demonstrated.
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Affiliation(s)
- Zainab Rehman
- Department of Physics, University of Warwick, Coventry, CV4 7AL, UK
| | - W Trent Franks
- Department of Physics, University of Warwick, Coventry, CV4 7AL, UK
| | | | | | | | - Steven P Brown
- Department of Physics, University of Warwick, Coventry, CV4 7AL, UK.
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2
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Goswami N, Sinha SK, Mondal P, Adhya S, Datta A, Maiti D. Distal meta-alkenylation of formal amines enabled by catalytic use of hydrogen-bonding anionic ligands. Chem 2023. [DOI: 10.1016/j.chempr.2022.12.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
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3
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Zhang J, Zheng H, Li X, Li N, Liu Y, Li T, Wang Y, Xing B. Direct Spectroscopic Evidence for Charge-Assisted Hydrogen-Bond Formation between Ionizable Organic Chemicals and Carbonaceous Materials. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:9356-9366. [PMID: 35729743 DOI: 10.1021/acs.est.2c00417] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
The direct evidence for the formation of charge-assisted hydrogen bond (CAHB) between the charged groups of ionizable organic chemicals (IOCs) and carbonaceous materials with similar proton affinity remains elusive. We therefore selected three pharmaceutical contaminants (PCs) as representative IOCs to provide the direct evidence of CAHB formation between IOCs and functionalized carbon nanotubes (CNTs) and its intensity/contribution to PC sorption on CNTs by NMR, FTIR, and DFT analyses. Sorption of PCs on functionalized CNTs resulted in the FTIR characteristic peak that appeared at a higher frequency (3787 cm-1) and the 1H NMR characteristic peak that emerged at an extremely low-field region (<18.0 ppm), which can be used as the direct spectroscopic evidence for CAHB formation. Both homonuclear CAHB (HM-CAHB, e.g., [O-H···O]-) and heteronuclear CAHB (HT-CAHB, e.g., [N+-H···O-]/[O-H···N]+) exhibited a much higher sorption energy (|Eads| ≥ 56.24 kJ/mol) than ordinary hydrogen bond (OHB, |Eads| ≤ 6.136 kJ/mol), leading to a greater sorption contribution (HM-/HT-CAHB ≥ 42.3%, OHB ≤ 36.5%) and irreversibility (hysteresis index: HM-/HT-CAHB ≥ 1.69, OHB ≤ 0.43) of PCs on CNTs. This work presents the direct evidence for CAHB formation between IOCs and CNTs, which is significant for understanding and predicting the environmental fate and risk of IOCs, thus providing new insights for controlling their pollution using specifically designed carbonaceous materials.
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Affiliation(s)
- Jinlong Zhang
- Department of Environmental Science, School of Geography and Tourism, Shaanxi Normal University, Xi'an 710119, China
- International Joint Research Centre of Shaanxi Province for Pollutants Exposure and Eco-environmental Health, Xi'an 710119, China
| | - Hao Zheng
- Institute of Coastal Environmental Pollution Control, Ministry of Education Key Laboratory of Marine Environment and Ecology, Frontiers Science Center for Deep Ocean Multispheres and Earth System, Ocean University of China, Qingdao 266100, China
| | - Xiaoyun Li
- Department of Environmental Science, School of Geography and Tourism, Shaanxi Normal University, Xi'an 710119, China
- International Joint Research Centre of Shaanxi Province for Pollutants Exposure and Eco-environmental Health, Xi'an 710119, China
| | - Nana Li
- Department of Environmental Science, School of Geography and Tourism, Shaanxi Normal University, Xi'an 710119, China
| | - Yifan Liu
- Department of Environmental Science, School of Geography and Tourism, Shaanxi Normal University, Xi'an 710119, China
| | - Tao Li
- Department of Environmental Science, School of Geography and Tourism, Shaanxi Normal University, Xi'an 710119, China
| | - Yue Wang
- Department of Environmental Science, School of Geography and Tourism, Shaanxi Normal University, Xi'an 710119, China
| | - Baoshan Xing
- Stockbridge School of Agriculture, University of Massachusetts, Amherst, Massachusetts 01003, United States
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4
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Štoček JR, Socha O, Císařová I, Slanina T, Dračínský M. Importance of Nuclear Quantum Effects for Molecular Cocrystals with Short Hydrogen Bonds. J Am Chem Soc 2022; 144:7111-7116. [PMID: 35394771 DOI: 10.1021/jacs.1c10885] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Many efforts have been recently devoted to the design and investigation of multicomponent pharmaceutical solids, such as salts and cocrystals. The experimental distinction between these solid forms is often challenging. Here, we show that the transformation of a salt into a cocrystal with a short hydrogen bond does not occur as a sharp phase transition but rather a smooth shift of the positional probability of the hydrogen atoms. A combination of solid-state NMR spectroscopy, X-ray diffraction, and diffuse reflectance measurements with density functional theory calculations that include nuclear quantum effects (NQEs) provides evidence of temperature-induced hydrogen atom shift in cocrystals with short hydrogen bonds. We demonstrate that for the predictions of the salt/cocrystal solid forms with short H-bonds, the computations have to include NQEs (particularly hydrogen nuclei delocalization) and temperature effects.
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Affiliation(s)
- Jakub Radek Štoček
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Flemingovo nám. 2, Prague 6 160 00, Czech Republic.,Department of Organic Chemistry, Faculty of Science, Charles University in Prague, Hlavova 2030, Prague 2 12840, Czech Republic
| | - Ondřej Socha
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Flemingovo nám. 2, Prague 6 160 00, Czech Republic
| | - Ivana Císařová
- Department of Inorganic Chemistry, Faculty of Science, Charles University in Prague, Hlavova 2030, Prague 2 12840, Czech Republic
| | - Tomáš Slanina
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Flemingovo nám. 2, Prague 6 160 00, Czech Republic
| | - Martin Dračínský
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Flemingovo nám. 2, Prague 6 160 00, Czech Republic
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5
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Ueda K, Higashi K, Moribe K, Taylor LS. Variable-Temperature NMR Analysis of the Thermodynamics of Polymer Partitioning between Aqueous and Drug-Rich Phases and Its Significance for Amorphous Formulations. Mol Pharm 2021; 19:100-114. [PMID: 34702040 DOI: 10.1021/acs.molpharmaceut.1c00664] [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] [Indexed: 12/28/2022]
Abstract
We previously reported that the polymers used in amorphous solid dispersion (ASD) formulations, such as polyvinylpyrrolidone (PVP), polyvinylpyrrolidone/vinyl acetate (PVP-VA), and hypromellose (HPMC), distribute into the drug-rich phase of ibuprofen (IBP) formed by liquid-liquid phase separation, resulting in a reduction in the maximum drug supersaturation in the aqueous phase. Herein, the mechanism underlying the partitioning of the polymer into the drug-rich phase was investigated from a thermodynamic perspective. The dissolved IBP concentration in the aqueous phase and the amount of polymer distributed into the IBP-rich phase were quantitatively analyzed in IBP-supersaturated solutions containing different polymers using variable-temperature solution-state nuclear magnetic resonance (NMR) spectroscopy. The polymer weight ratio in the IBP-rich phase increased at higher temperatures, leading to a more notable reduction of IBP amorphous solubility. Among the polymers, the amorphous solubility reduction was the greatest for the PVP-VA solution at lower temperatures, while HPMC reduced the amorphous solubility to the greatest extent at higher temperatures. The change in the order of polymer impact on the amorphous solubility resulted from the differences in the temperature dependency of polymer partitioning. The van't Hoff plot of the polymer partition coefficient revealed that both enthalpy and entropy changes for polymer transfer into the IBP-rich phase from the aqueous phase (ΔHaqueous→IBP-rich and ΔSaqueous→IBP-rich) gave positive values for most of the measured temperature range, indicating that polymer partitioning into the IBP-rich phase was an endothermic but entropically favorable process. The polymer transfer into the IBP-rich phase was more endothermic for HPMC than for PVP and PVP-VA. The solid-state NMR analysis of the IBP/polymer ASD implied that the newly formed IBP/polymer interactions in the IBP-rich phase upon polymer incorporation were weaker for HPMC, providing a rationale for the larger positive transfer enthalpy for HPMC. The change in Gibbs free energy for polymer transfer (ΔGaqueous→IBP-rich) showed negative values across the experimental temperature range, decreasing with an increase in temperature, indicating that the distribution of the polymer into the IBP-rich phase is favored at higher temperatures. Moreover, ΔGaqueous→IBP-rich for HPMC showed the greatest decrease with the temperature, likely reflecting the temperature-induced dehydration of HPMC in the aqueous phase. This study contributes fundamental insights into the phenomenon of polymer partitioning into drug-rich phases, furthering the understanding of achievable supersaturation levels and ultimately providing information on polymer selection for ASD formulations.
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Affiliation(s)
- Keisuke Ueda
- Graduate School of Pharmaceutical Sciences, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba 260-8675, Japan
| | - Kenjirou Higashi
- Graduate School of Pharmaceutical Sciences, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba 260-8675, Japan
| | - Kunikazu Moribe
- Graduate School of Pharmaceutical Sciences, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba 260-8675, Japan
| | - Lynne S Taylor
- Department of Industrial and Physical Pharmacy, College of Pharmacy, Purdue University, West Lafayette, Indiana 47907, United States
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6
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Zarycz MNC, Schiel MA, Angelina E, Enriz RD. Covalence and π-electron delocalization influence on hydrogen bonds in proton transfer process of o-hydroxy aryl Schiff bases: A combined NMR and QTAIM analysis. J Chem Phys 2021; 155:054307. [PMID: 34364326 DOI: 10.1063/5.0058422] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Within the framework of the density functional theory approach, we studied the relationship between the chemical nature of intramolecular hydrogen bonds (HBs) and nuclear magnetic resonance (NMR) parameters, J-couplings and 1H-chemical shifts [δ(1H)], of the atoms involved in such bonds in o-hydroxyaryl Schiff bases during the proton transfer process. For the first time, the shape of the dependence of the degree of covalence in HBs on 1J(N-H), 1J(O-H), 2hJ(O-N), and δ(1H) during the proton transfer process in o-hydroxyaryl Schiff bases was analyzed. Parameters obtained from Bader's theory of atoms in molecules were used to assess the dependence of covalent character in HBs with both the NMR properties. The influence of π-electronic delocalization on 2hJ(N-O) under the proton transfer process was investigated. 2hJ(O-N) in a Mannich base was also studied in order to compare the results with an unsaturated system. In addition, substituent effects on the phenolic ring were investigated. Our results indicate that the covalent character of HBs on both sides of the transition state undergoes a smooth exponential increase as the δ(1H) moves downfield. The degree of covalence of the N⋯H (O⋯H) bond increases linearly as 1J(N-H) (1J(O-H)) becomes more negative, even after reaching the transition state. Non-vanishing values of spin dipolar (SD) and paramagnetic spin orbital terms of 2hJ(O-N) show that π-electronic delocalization has a non-negligible effect on tautomeric equilibrium and gives evidence of the presence of the resonance assisted HB.Variation of the SD term of 2hJ(O-N) follows a similar pattern as the change in the para-delocalization aromaticity index of the chelate ring.
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Affiliation(s)
- M Natalia C Zarycz
- Facultad de Química, Bioquímica y Farmacia, Universidad Nacional de San Luis; Instituto Multidisciplinario de Investigaciones Biológicas (IMIBIO-SL). CONICET, Ejército de los Andes 950, 5700 San Luis, Argentina
| | - M Ayelén Schiel
- Facultad de Química, Bioquímica y Farmacia, Universidad Nacional de San Luis; Instituto Multidisciplinario de Investigaciones Biológicas (IMIBIO-SL). CONICET, Ejército de los Andes 950, 5700 San Luis, Argentina
| | - Emilio Angelina
- Laboratorio de Estructura Molecular y Propiedades, Facultad de Ciencias Exactas y Naturales y Agrimensura, Universidad Nacional del Nordeste; Instituto de Química Básica y Aplicada (IQUIBA-NEA). CONICET, Avda. Libertad 5460, 3400 Corrientes, Argentina
| | - Ricardo D Enriz
- Facultad de Química, Bioquímica y Farmacia, Universidad Nacional de San Luis; Instituto Multidisciplinario de Investigaciones Biológicas (IMIBIO-SL). CONICET, Ejército de los Andes 950, 5700 San Luis, Argentina
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7
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Yao HYY, Wang JQ, Yin JY, Nie SP, Xie MY. A review of NMR analysis in polysaccharide structure and conformation: Progress, challenge and perspective. Food Res Int 2021; 143:110290. [PMID: 33992390 DOI: 10.1016/j.foodres.2021.110290] [Citation(s) in RCA: 146] [Impact Index Per Article: 48.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2020] [Revised: 02/28/2021] [Accepted: 02/28/2021] [Indexed: 12/31/2022]
Abstract
Nuclear magnetic resonance (NMR) has been widely used as an analytical chemistry technique to investigate the molecular structure and conformation of polysaccharides. Combined with 1D spectra, chemical shifts and coupling constants in both homo- and heteronuclear 2D NMR spectra are able to infer the linkage and sequence of sugar residues. Besides, NMR has also been applied in conformation, quantitative analysis, cell wall in situ, degradation, polysaccharide mixture interaction analysis, as well as carbohydrates impurities profiling. This review summarizes the principle and development of NMR in polysaccharides analysis, and provides NMR spectra data collections of some common polysaccharides. It will help to promote the application of NMR in complex polysaccharides of biochemical interest, and provide valuable information on commercial polysaccharide products.
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Affiliation(s)
- Hao-Ying-Ye Yao
- State Key Laboratory of Food Science and Technology, China-Canada Joint Lab of Food Science and Technology (Nanchang), Nanchang University, 235 Nanjing East Road, Nanchang 330047, China.
| | - Jun-Qiao Wang
- State Key Laboratory of Food Science and Technology, China-Canada Joint Lab of Food Science and Technology (Nanchang), Nanchang University, 235 Nanjing East Road, Nanchang 330047, China.
| | - Jun-Yi Yin
- State Key Laboratory of Food Science and Technology, China-Canada Joint Lab of Food Science and Technology (Nanchang), Nanchang University, 235 Nanjing East Road, Nanchang 330047, China.
| | - Shao-Ping Nie
- State Key Laboratory of Food Science and Technology, China-Canada Joint Lab of Food Science and Technology (Nanchang), Nanchang University, 235 Nanjing East Road, Nanchang 330047, China.
| | - Ming-Yong Xie
- State Key Laboratory of Food Science and Technology, China-Canada Joint Lab of Food Science and Technology (Nanchang), Nanchang University, 235 Nanjing East Road, Nanchang 330047, China; National R&D Center for Freshwater Fish Processing, Jiangxi Normal University, Nanchang, Jiangxi 330022, China.
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8
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Chen J, Zeng Q, Tian D, Lin Y, Chen Z. High-resolution 2-D NMR spectroscopy based on the Radon transform and pure shift technique for studying chemical shifts perturbations. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2021; 59:346-353. [PMID: 31967670 DOI: 10.1002/mrc.5000] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2019] [Revised: 01/11/2020] [Accepted: 01/19/2020] [Indexed: 06/10/2023]
Abstract
Chemical shift plays an important role in molecular analysis. However, chemical shifts are influenced by temperature, solvent concentration, pressure, and so forth. Therefore, measuring chemical shift perturbations caused by these factors is helpful to molecular studies. A new form of 2-D spectroscopy (projection spectroscopy) has been introduced whose indirect dimension is derived by implementing the Radon transform on a series of conventional 1-D proton spectra and indicates such perturbations. However, signal overlap may exist in the conventional 1-D spectra and hence in the resulting projection spectra, hampering clear multiplet analysis and accurate extraction of perturbations. Here, the pure shift decoupling technique is employed to obtain clearer projection spectrum with higher spectral resolution. The combination of pure shift technique and the Radon transform is helpful to accurately extract chemical shift perturbations. It is believed that this application will open up a vast prospect for molecular analysis.
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Affiliation(s)
- Jinyong Chen
- Department of Electronic Science, Fujian Provincial Key Laboratory of Plasma and Magnetic Resonance, State Key Laboratory for Physical Chemistry of Solid Surfaces, Xiamen University, Xiamen, China
| | - Qing Zeng
- Department of Electronic Science, Fujian Provincial Key Laboratory of Plasma and Magnetic Resonance, State Key Laboratory for Physical Chemistry of Solid Surfaces, Xiamen University, Xiamen, China
| | - Dan Tian
- Department of Electronic Science, Fujian Provincial Key Laboratory of Plasma and Magnetic Resonance, State Key Laboratory for Physical Chemistry of Solid Surfaces, Xiamen University, Xiamen, China
| | - Yanqin Lin
- Department of Electronic Science, Fujian Provincial Key Laboratory of Plasma and Magnetic Resonance, State Key Laboratory for Physical Chemistry of Solid Surfaces, Xiamen University, Xiamen, China
- Shenzhen Research Institute of Xiamen University, Shenzhen, China
| | - Zhong Chen
- Department of Electronic Science, Fujian Provincial Key Laboratory of Plasma and Magnetic Resonance, State Key Laboratory for Physical Chemistry of Solid Surfaces, Xiamen University, Xiamen, China
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9
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Batista LN, Vasconcelos TL, Senna CA, Archanjo BS, Miguez E, A S San Gil R, Tavares MIB. Impact of nanoconfinement on acetylacetone Equilibria in Ordered Mesoporous Silicates. NANOTECHNOLOGY 2020; 31:355706. [PMID: 32434178 DOI: 10.1088/1361-6528/ab94db] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Nanoconfinement is one of the most intriguing nanoscale effects and affects several physical and chemical properties of molecules and materials, including viscosity, reaction kinetics, and glass transition temperature. In this work, liquid nuclear magnetic resonance (NMR) was used to analyze the behavior of 2,4-pentadienone in ordered mesoporous materials with a pore diameter of between 3 and 10 nm. The liquid NMR results showed meaningful changes in the hydrogen chemical shift and the keto-enol chemical equilibrium, which were associated with the pore diameter, allowing the authors to observe the effects of nanoconfinement. An interesting phenomenon was observed where the chemical equilibria of 2,4-pentadienone confined in a mesoporous material with a pore diameter of 3.5 nm was similar to that obtained with free (bulk) 2,4-pentadienone in larger pore materials. Another interesting result was observed for the enthalpy and entropy of the tautomeric equilibria of 2,4-pentadienone confined in mesoporous materials with a 5.5 nm pore diameter being -7.9 kJ mol-1 and -15.9 J mol-1.K. These values are similar to those obtained by dimethyl sulfoxide. This phenomenon indicates the possible use of ordered mesoporous materials as a reaction substitute in organic solvents. It was further observed that while the values of enthalpy (ΔH) and entropy (ΔS) had been modified by confinement, the Gibbs free energy (ΔG) value remained closer to that observed in free (bulk) 2,4-pentadienone. It is expected that this study will help in understanding the effects of nanoconfinement and provide a simple method to employ NMR techniques to analyze these phenomena.
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Affiliation(s)
- Luciano N Batista
- Instituto Nacional de Metrologia, Qualidade e Tecnologia, Avenida Nossa Senhora das Graças, 50, 25250020, Duque de Caxias, Rio de Janeiro, Brazil. Instituto de Macromoléculas Professora Eloisa Mano, Universidade Federal do Rio de Janeiro, Av. Horácio Macedo, 2030, 21941-598, Rio de Janeiro, Brazil
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10
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Mann SK, Devgan MK, Franks WT, Huband S, Chan CL, Griffith J, Pugh D, Brooks NJ, Welton T, Pham TN, McQueen LL, Lewandowski JR, Brown SP. MAS NMR Investigation of Molecular Order in an Ionic Liquid Crystal. J Phys Chem B 2020; 124:4975-4988. [PMID: 32412761 PMCID: PMC7341529 DOI: 10.1021/acs.jpcb.0c02328] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The structure and molecular order in the thermotropic ionic liquid crystal (ILC), [choline][geranate(H)octanoate], an analogue of Choline And GEranate (CAGE), which has potential for use as a broad-spectrum antimicrobial and transdermal and oral delivery agent, were investigated by magic-angle spinning (MAS) nuclear magnetic resonance (NMR), polarizing optical microscopy, small-angle X-ray scattering (SAXS), and mass spectrometry. Mass spectrometry and the 1H NMR chemical shift reveal that CAGE-oct is a dynamic system, with metathesis (the exchange of interacting ions) and hydrogen exchange occurring between hydrogen-bonded/ionic complexes such as [(choline)(geranate)(H)(octanoate)], [(choline)(octanoate)2(H)], and [(choline)(geranate)2(H)]. These clusters, which are shown by mass spectrometry to be significantly more stable than expected for typical electrostatic ion clusters, involve hydrogen bonding between the carboxylic acid, carboxylate, and hydroxyl groups, with rapid hydrogen bond breaking and re-formation observed to average the 1H chemical shifts. The formation of a partial bilayer liquid crystal (LC) phase was identified by SAXS and polarizing optical microscopy at temperatures below ∼293 K. The occurrence of this transition close to room temperature could be utilized as a potential temperature-induced "switch" of the anisotropic properties for particular applications. The presence of an isotropic component of approximately 23% was observed to coexist with the LC phase, as detected by polarizing optical microscopy and quantified by both 1H-13C dipolar-chemical shift correlation (DIPSHIFT) and 1H double-quantum (DQ) MAS NMR experiments. At temperatures above the LC-to-isotropic transition, intermediate-range order (clustering of polar and nonpolar domains), a feature of many ILs, persists. Site-specific order parameters for the LC phase of CAGE-oct were obtained from the MAS NMR measurement of the partially averaged 13C-1H dipolar couplings (DCH) by cross-polarization (CP) build-up curves and DIPSHIFT experiments, and 1H-1H dipolar couplings (DHH) by double-quantum (DQ) build-up curves. The corresponding order parameters, SCH and SHH, are in the range 0-0.2 and are lower compared to those for smectic (i.e., layered) phases of conventional nonionic liquid crystals, resembling those of lamellar phases formed by lyotropic surfactant-solvent systems.
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Affiliation(s)
- Sarah K Mann
- Department of Physics, University of Warwick, Coventry CV4 7AL, U.K
| | - Mohit K Devgan
- Department of Chemistry, Imperial College London, London SW7 2AZ, U.K
| | - W Trent Franks
- Department of Physics, University of Warwick, Coventry CV4 7AL, U.K.,Department of Chemistry, University of Warwick, Coventry CV4 7AL, U.K
| | - Steven Huband
- Department of Physics, University of Warwick, Coventry CV4 7AL, U.K
| | - Chi Long Chan
- Department of Chemistry, Imperial College London, London SW7 2AZ, U.K
| | - Jeraime Griffith
- Department of Chemistry, Imperial College London, London SW7 2AZ, U.K
| | - David Pugh
- Department of Chemistry, Imperial College London, London SW7 2AZ, U.K
| | - Nicholas J Brooks
- Department of Chemistry, Imperial College London, London SW7 2AZ, U.K
| | - Tom Welton
- Department of Chemistry, Imperial College London, London SW7 2AZ, U.K
| | - Tran N Pham
- GSK R&D, Stevenage, Hertfordshire SG1 2NY, U.K
| | - Lisa L McQueen
- GSK R&D, Collegeville, Pennsylvania 19426, United States
| | | | - Steven P Brown
- Department of Physics, University of Warwick, Coventry CV4 7AL, U.K
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11
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Luo Y, Ma H, Sun Y, Che P, Nie X, Wang T, Xu J. Understanding and Measurement for the Binding Energy of Hydrogen bonds of Biomass-Derived Hydroxyl Compounds. J Phys Chem A 2018; 122:843-848. [DOI: 10.1021/acs.jpca.7b10637] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- Yang Luo
- State
Key Laboratory of Catalysis, Dalian Institute of Chemical Physics,
Chinese Academy of Sciences, Dalian National Laboratory for Clean Energy, Dalian 116023, P. R. China
- University of Chinese Academy of Sciences, Beijing 100049, P. R. China
| | - Hong Ma
- State
Key Laboratory of Catalysis, Dalian Institute of Chemical Physics,
Chinese Academy of Sciences, Dalian National Laboratory for Clean Energy, Dalian 116023, P. R. China
| | - Yuxia Sun
- State
Key Laboratory of Catalysis, Dalian Institute of Chemical Physics,
Chinese Academy of Sciences, Dalian National Laboratory for Clean Energy, Dalian 116023, P. R. China
- University of Chinese Academy of Sciences, Beijing 100049, P. R. China
| | - Penghua Che
- State
Key Laboratory of Catalysis, Dalian Institute of Chemical Physics,
Chinese Academy of Sciences, Dalian National Laboratory for Clean Energy, Dalian 116023, P. R. China
| | - Xin Nie
- State
Key Laboratory of Catalysis, Dalian Institute of Chemical Physics,
Chinese Academy of Sciences, Dalian National Laboratory for Clean Energy, Dalian 116023, P. R. China
| | - Tianlong Wang
- State
Key Laboratory of Catalysis, Dalian Institute of Chemical Physics,
Chinese Academy of Sciences, Dalian National Laboratory for Clean Energy, Dalian 116023, P. R. China
| | - Jie Xu
- State
Key Laboratory of Catalysis, Dalian Institute of Chemical Physics,
Chinese Academy of Sciences, Dalian National Laboratory for Clean Energy, Dalian 116023, P. R. China
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12
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Spin System Modeling of Nuclear Magnetic Resonance Spectra for Applications in Metabolomics and Small Molecule Screening. Anal Chem 2017; 89:12201-12208. [PMID: 29058410 DOI: 10.1021/acs.analchem.7b02884] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The exceptionally rich information content of nuclear magnetic resonance (NMR) spectra is routinely used to identify and characterize molecules and molecular interactions in a wide range of applications, including clinical biomarker discovery, drug discovery, environmental chemistry, and metabolomics. The set of peak positions and intensities from a reference NMR spectrum generally serves as the identifying signature for a compound. Reference spectra normally are collected under specific conditions of pH, temperature, and magnetic field strength, because changes in conditions can distort the identifying signatures of compounds. A spin system matrix that parametrizes chemical shifts and coupling constants among spins provides a much richer feature set for a compound than a spectral signature based on peak positions and intensities. Spin system matrices expand the applicability of NMR spectral libraries beyond the specific conditions under which data were collected. In addition to being able to simulate spectra at any field strength, spin parameters can be adjusted to systematically explore alterations in chemical shift patterns due to variations in other experimental conditions, such as compound concentration, pH, or temperature. We present methodology and software for efficient interactive optimization of spin parameters against experimental 1D-1H NMR spectra of small molecules. We have used the software to generate spin system matrices for a set of key mammalian metabolites and are also using the software to parametrize spectra of small molecules used in NMR-based ligand screening. The software, along with optimized spin system matrix data for a growing number of compounds, is available from http://gissmo.nmrfam.wisc.edu/ .
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Abstract
Metal(H2O2) complexes have been implicated in kinetic and computational studies but have never been observed. Accordingly, H2O2 has been described as a very weak ligand. We report the first metal(H2O2) adduct, which is made possible by incorporating intramolecular hydrogen-bonding interactions with bound H2O2. This Zn(II)(H2O2) complex decays in solution by a second-order process that is slow enough to enable characterization of this species by X-ray crystallography. This report speaks to the intermediacy of metal(H2O2) adducts in chemistry and biology and opens the door to exploration of these species in oxidation catalysis.
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Affiliation(s)
- Christian M Wallen
- Department of Chemistry, Emory University , 1515 Dickey Drive, Atlanta, Georgia 30322, United States
| | - John Bacsa
- Department of Chemistry, Emory University , 1515 Dickey Drive, Atlanta, Georgia 30322, United States
| | - Christopher C Scarborough
- Department of Chemistry, Emory University , 1515 Dickey Drive, Atlanta, Georgia 30322, United States
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14
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White PB, Hong M. (15)N and (1)H Solid-State NMR Investigation of a Canonical Low-Barrier Hydrogen-Bond Compound: 1,8-Bis(dimethylamino)naphthalene. J Phys Chem B 2015; 119:11581-9. [PMID: 26244754 DOI: 10.1021/acs.jpcb.5b06171] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Strong or low-barrier hydrogen bonds have often been proposed in proteins to explain enzyme catalysis and proton-transfer reactions. So far (1)H chemical shifts and scalar couplings have been used as the main NMR spectroscopic signatures for strong H-bonds. In this work, we report simultaneous measurements of (15)N and (1)H chemical shifts and N-H bond lengths by solid-state NMR in (15)N-labeled 1,8-bis(dimethylamino)naphthalene (DMAN), which contains a well-known strong NHN H-bond. We complexed DMAN with three different counteranions to examine the effects of the chemical environment on the H-bond lengths and chemical shifts. All three DMAN compounds exhibit significantly elongated N-H distances compared to the covalent bond length, and the (1)H(N) chemical shifts are larger than ∼17 ppm, consistent with strong NHN H-bonds in the DMAN cation. However, the (15)N and (1)H chemical shifts and the precise N-H distances differ among the three compounds, and the (15)N chemical shifts show opposite dependences on the proton localization from the general trend in organic compounds, indicating the significant effects of the counteranions on the electronic structure of the H-bond. These data provide useful NMR benchmarks for strong H-bonds and caution against the sole reliance on chemical shifts for identifying strong H-bonds in proteins since neighboring side chains can exert influences on chemical shifts similar to those of the bulky organic anions in DMAN. Instead, N-H bond lengths should be measured, in conjunction with chemical shifts, as a more fundamental parameter of H-bond strength.
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Affiliation(s)
- Paul B White
- Department of Chemistry, Massachusetts Institute of Technology , 170 Albany Street, Cambridge, Massachusetts 02139, United States
| | - Mei Hong
- Department of Chemistry, Massachusetts Institute of Technology , 170 Albany Street, Cambridge, Massachusetts 02139, United States
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15
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Che P, Lu F, Nie X, Huang Y, Yang Y, Wang F, Xu J. Hydrogen bond distinction and activation upon catalytic etherification of hydroxyl compounds. Chem Commun (Camb) 2015; 51:1077-80. [DOI: 10.1039/c4cc08467e] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The slope (A) of the linear correlation between ln δand 1/Tcan distinguish intra- and intermolecular H-bonds and predict their reactivities.
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Affiliation(s)
- Penghua Che
- State Key Laboratory of Catalysis
- Dalian Institute of Chemical Physics
- Chinese Academy of Sciences
- Dalian National Laboratory for Clean Energy
- Dalian 116023
| | - Fang Lu
- State Key Laboratory of Catalysis
- Dalian Institute of Chemical Physics
- Chinese Academy of Sciences
- Dalian National Laboratory for Clean Energy
- Dalian 116023
| | - Xin Nie
- State Key Laboratory of Catalysis
- Dalian Institute of Chemical Physics
- Chinese Academy of Sciences
- Dalian National Laboratory for Clean Energy
- Dalian 116023
| | - Yizheng Huang
- State Key Laboratory of Catalysis
- Dalian Institute of Chemical Physics
- Chinese Academy of Sciences
- Dalian National Laboratory for Clean Energy
- Dalian 116023
| | - Yanliang Yang
- State Key Laboratory of Catalysis
- Dalian Institute of Chemical Physics
- Chinese Academy of Sciences
- Dalian National Laboratory for Clean Energy
- Dalian 116023
| | - Feng Wang
- State Key Laboratory of Catalysis
- Dalian Institute of Chemical Physics
- Chinese Academy of Sciences
- Dalian National Laboratory for Clean Energy
- Dalian 116023
| | - Jie Xu
- State Key Laboratory of Catalysis
- Dalian Institute of Chemical Physics
- Chinese Academy of Sciences
- Dalian National Laboratory for Clean Energy
- Dalian 116023
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16
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Battistel MD, Azurmendi HF, Yu B, Freedberg DI. NMR of glycans: shedding new light on old problems. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2014; 79:48-68. [PMID: 24815364 DOI: 10.1016/j.pnmrs.2014.01.001] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2013] [Accepted: 01/10/2014] [Indexed: 06/03/2023]
Abstract
The diversity in molecular arrangements and dynamics displayed by glycans renders traditional NMR strategies, employed for proteins and nucleic acids, insufficient. Because of the unique properties of glycans, structural studies often require the adoption of a different repertoire of tailor-made experiments and protocols. We present an account of recent developments in NMR techniques that will deepen our understanding of structure-function relations in glycans. We open with a survey and comparison of methods utilized to determine the structure of proteins, nucleic acids and carbohydrates. Next, we discuss the structural information obtained from traditional NMR techniques like chemical shifts, NOEs/ROEs, and coupling-constants, along with the limitations imposed by the unique intrinsic characteristics of glycan structure on these approaches: flexibility, range of conformers, signal overlap, and non-first-order scalar (strong) coupling. Novel experiments taking advantage of isotopic labeling are presented as an option for overcoming spectral overlap and raising sensitivity. Computational tools used to explore conformational averaging in conjunction with NMR parameters are described. In addition, recent developments in hydroxyl detection and hydrogen bond detection in protonated solvents, in contrast to traditional sample preparations in D2O for carbohydrates, further increase the tools available for both structure information and chemical shift assignments. We also include previously unpublished data in this context. Accurate determination of couplings in carbohydrates has been historically challenging due to the common presence of strong-couplings. We present new strategies proposed for dealing with their influence on NMR signals. We close with a discussion of residual dipolar couplings (RDCs) and the advantages of using (13)C isotope labeling that allows gathering one-bond (13)C-(13)C couplings with a recently improved constant-time COSY technique, in addition to the commonly measured (1)H-(13)C RDCs.
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Affiliation(s)
- Marcos D Battistel
- Laboratory of Bacterial Polysaccharides, Center for Biologics Evaluation and Research, Food and Drug Administration, 1401 Rockville Pike, Rockville, MD 20852-1448, United States
| | - Hugo F Azurmendi
- Laboratory of Bacterial Polysaccharides, Center for Biologics Evaluation and Research, Food and Drug Administration, 1401 Rockville Pike, Rockville, MD 20852-1448, United States
| | - Bingwu Yu
- Laboratory of Bacterial Polysaccharides, Center for Biologics Evaluation and Research, Food and Drug Administration, 1401 Rockville Pike, Rockville, MD 20852-1448, United States
| | - Darón I Freedberg
- Laboratory of Bacterial Polysaccharides, Center for Biologics Evaluation and Research, Food and Drug Administration, 1401 Rockville Pike, Rockville, MD 20852-1448, United States.
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17
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Nadal-Ferret M, Gelabert R, Moreno M, Lluch JM. Are there really low-barrier hydrogen bonds in proteins? The case of photoactive yellow protein. J Am Chem Soc 2014; 136:3542-52. [PMID: 24548066 DOI: 10.1021/ja4116617] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
For a long time, low-barrier hydrogen bonds (LBHBs) have been proposed to exist in many enzymes and to play an important role in their catalytic function, but the proof of their existence has been elusive. The transient formation of an LBHB in a protein system has been detected for the first time using neutron diffraction techniques on a photoactive yellow protein (PYP) crystal in a study published in 2009 (Yamaguchi, S.; et al. Proc. Natl. Acad. Sci. U.S.A. 2009, 106, 440-444). However, very recent theoretical studies based on electronic structure calculations and NMR resonance experiments on PYP in solution (Saito, K.; et al. Proc. Natl. Acad. Sci. U.S.A. 2012, 109, 167-172) strongly indicate that there is not such an LBHB. By means of electronic structure calculations combined with the solution of the nuclear Schrödinger equation, we analyze here under which conditions an LBHB can exist in PYP, thus leading to a more reasonable and conciliating understanding of the above-mentioned studies.
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Affiliation(s)
- Marc Nadal-Ferret
- Departament de Química and ‡Institut de Biotecnologia i de Biomedicina, Universitat Autònoma de Barcelona , 08193 Bellaterra (Barcelona), Spain
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18
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19
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Biliškov N, Kojić-Prodić B, Mali G, Molčanov K, Stare J. A Partial Proton Transfer in Hydrogen Bond O−H···O in Crystals of Anhydrous Potassium and Rubidium Complex Chloranilates. J Phys Chem A 2011; 115:3154-66. [DOI: 10.1021/jp112380f] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Affiliation(s)
- Nikola Biliškov
- Rudjer Bošković Institute, POB 180, HR-10002 Zagreb, Croatia
| | | | - Gregor Mali
- National Institute of Chemistry, Hajdrihova 19, 1001 Ljubljana, Slovenia
- EN-FIST Centre of Excellence, Dunajska c. 156, SI-1000 Ljubljana
| | | | - Jernej Stare
- National Institute of Chemistry, Hajdrihova 19, 1001 Ljubljana, Slovenia
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20
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Miran MS, Kinoshita H, Yasuda T, Susan MABH, Watanabe M. Hydrogen bonds in protic ionic liquids and their correlation with physicochemical properties. Chem Commun (Camb) 2011; 47:12676-8. [DOI: 10.1039/c1cc14817f] [Citation(s) in RCA: 94] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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21
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Ortiz-Sánchez JM, Gelabert R, Moreno M, Lluch JM. Electronic-structure and quantum dynamical study of the photochromism of the aromatic Schiff base salicylideneaniline. J Chem Phys 2008; 129:214308. [DOI: 10.1063/1.3032215] [Citation(s) in RCA: 84] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
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22
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Filarowski A, Koll A, Hansen PE, Kluba M. Density Functional Theory Study of Intramolecular Hydrogen Bonding and Proton Transfer in o-Hydroxyaryl Ketimines. J Phys Chem A 2008; 112:3478-85. [DOI: 10.1021/jp076991l] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Aleksander Filarowski
- Faculty of Chemistry, University of Wrocław, F. Joliot-Curie 14, 50-383 Wrocław, Poland, and Department of Life Sciences and Chemistry, Roskilde University, P.O. Box 260, DK-4000 Roskilde, Denmark
| | - Aleksander Koll
- Faculty of Chemistry, University of Wrocław, F. Joliot-Curie 14, 50-383 Wrocław, Poland, and Department of Life Sciences and Chemistry, Roskilde University, P.O. Box 260, DK-4000 Roskilde, Denmark
| | - Poul Erik Hansen
- Faculty of Chemistry, University of Wrocław, F. Joliot-Curie 14, 50-383 Wrocław, Poland, and Department of Life Sciences and Chemistry, Roskilde University, P.O. Box 260, DK-4000 Roskilde, Denmark
| | - Malgorzata Kluba
- Faculty of Chemistry, University of Wrocław, F. Joliot-Curie 14, 50-383 Wrocław, Poland, and Department of Life Sciences and Chemistry, Roskilde University, P.O. Box 260, DK-4000 Roskilde, Denmark
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23
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Lankau T, Yu CH. The relationship between the bond length and the difference in proton affinities for the observation of heteronuclear low barrier hydrogen bonds. Chem Phys Lett 2007. [DOI: 10.1016/j.cplett.2006.11.062] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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24
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25
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The relationship between the energy of activation for the proton-movement and the difference in proton affinities of bonded partners in double well hydrogen bonds. Chem Phys Lett 2006. [DOI: 10.1016/j.cplett.2006.04.067] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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26
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Schlund S, Mladenovic M, Basílio Janke EM, Engels B, Weisz K. Geometry and Cooperativity Effects in Adenosine−Carboxylic Acid Complexes. J Am Chem Soc 2005; 127:16151-8. [PMID: 16287303 DOI: 10.1021/ja0531430] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
NMR experiments and theoretical investigations were performed on hydrogen bonded complexes of specifically 1- and 7-15N-labeled adenine nucleosides with carboxylic acids. By employing a freonic solvent of CDClF2 and CDF3, NMR spectra were acquired at temperatures as low as 123 K, where the regime of slow hydrogen bond exchange is reached and several higher-order complexes were found to coexist in solution. Unlike acetic acid, chloroacetic acid forms Watson-Crick complexes with the proton largely displaced from oxygen to the nitrogen acceptor in an ion pairing structure. Calculated geometries and chemical shifts of the proton in the hydrogen bridge favorably agree with experimentally determined values if vibrational averaging and solvent effects are taken into account. The results indicate that binding a second acidic ligand at the adenine Hoogsteen site in a ternary complex weakens the hydrogen bond to the Watson-Crick bound carboxylic acid. However, substituting a second adenine nucleobase for a carboxylic acid in the trimolecular complex leads to cooperative binding at Watson-Crick and Hoogsteen faces of adenosine.
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Affiliation(s)
- Sebastian Schlund
- Institut für Organische Chemie, Universität Würzburg, Am Hubland, D-97070 Würzburg, Germany
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27
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28
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Gelabert R, Moreno M, Lluch JM, Lledós A, Heinekey DM. Determination of the Temperature Dependence of the H−D Spin−Spin Coupling Constant and the Isotope Effect on the Proton Chemical Shift for the Compressed Dihydride Complex [Cp*Ir(P−P)H2]2+. J Am Chem Soc 2005; 127:5632-40. [PMID: 15826203 DOI: 10.1021/ja043011r] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Complex [CpIr(dmpm)H(2)](2+) (dmpm = bis(dimethylphosphino)methane) has been reported to display temperature-dependent spin-spin coupling constant ((1)J(HD)) and isotope effect on the (1)H NMR chemical shift (Deltadelta). A combined electronic structure density functional theory + quantum nuclear dynamics study is used to determine from first-principles the unusual temperature dependence of the spin-spin coupling constant. It is found that the potential energy surface describing the motion of the Ir-H(2) unit has a deeper minimum in the dihydride region and is characterized by important anharmonicities. These anomalies affect the nature of the vibrational states of the unit and are the main reason for the unusual temperature dependence of (1)J(HD) and Deltadelta. These results suggest experimental tests to identify compressed dihydride transition metal complexes.
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Affiliation(s)
- Ricard Gelabert
- Departament de Química, Universitat Autonoma de Barcelona, 08193 Bellaterra, Barcelona, Spain
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29
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Gelabert R, Moreno M, Lluch JM, Lledós A, Pons V, Heinekey DM. Synthesis and Properties of Compressed Dihydride Complexes of Iridium: Theoretical and Spectroscopic Investigations. J Am Chem Soc 2004; 126:8813-22. [PMID: 15250735 DOI: 10.1021/ja048775l] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Reaction of [Cp*Ir(P-P)Cl][B(C6F5)4] (P-P = bisdimethydiphosphinomethane (dmpm), bisdiphenyldiphosphinomethane (dppm)) with [Et3Si][B(C6F5)4] in methylene chloride under 1 atm of hydrogen gas affords the dicationic compressed dihydride complexes [Cp*Ir(P-P)H2][B(C6F5)4]2. These dicationic complexes are highly acidic and are very readily deprotonated to the corresponding monohydride cations. When the preparative reaction is carried out under HD gas, the hydride resonance exhibits JHD = 7-9 Hz, depending upon the temperature of observation, with higher values of JHD observed at higher temperatures. A thermally labile rhodium analogue, [CpRh(dmpm)(H2)][B(C6F5)4]2, was prepared similarly. A sample prepared with HD gas gave JHD = 31 Hz and J(HRh) = 31 Hz, allowing the Rh complex to be identified as a dihydrogen complex. Quantum dynamics calculations on a density functional theory (DFT) potential energy surface have been used to explore the structure of the Ir complexes, with particular emphasis on the nature of the potential energy surface governing the interaction between the two hydride ligands and the Ir center.
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Affiliation(s)
- Ricard Gelabert
- Departament de Química, Universitat Autonoma de Barcelona, 08193 Bellaterra, Barcelona, Spain
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30
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Abstract
The complex formed between 4-methylpyridine and pentachlorophenol (4MPPCP) crystallizes in a triclinic space group. If the same complex is synthesized from deuterated pentachlorophenol (4MPPCP-d1), it crystallizes in an entirely different monoclinic polymorph. Solid-state NMR of samples synthesized with a full range of deuteration levels, crystallized from solution or the melt, and in the presence or absence of seeds confirms that the isotopomers indeed have different thermodynamically stable crystal structures. The phenomenon is apparently due to very different hydrogen bond strengths between the two polymorphs.
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Affiliation(s)
- Jun Zhou
- Department of Chemistry, University of Nebraska at Lincoln, Lincoln, Nebraska 68588, USA
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31
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Stare J, Jezierska A, Ambrozic G, Kosir IJ, Kidric J, Koll A, Mavri J, Hadzi D. Density Functional Calculation of the 2D Potential Surface and Deuterium Isotope Effect on 13C Chemical Shifts in Picolinic Acid N-Oxide. Comparison with Experiment. J Am Chem Soc 2004; 126:4437-43. [PMID: 15053634 DOI: 10.1021/ja021345f] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
2D free energy surfaces V = V(rOH, rO...O) for the intramolecular H-bond in the title compound were calculated by the DFT method and used in the calculation of primary and secondary chemical shifts of the compound dissolved in chloroform and acetonitrile. Solvent effects were accounted for by the SCRF/PCM method. The corresponding two-dimensional chemical shift surfaces with included solvent reaction field were obtained using the Continuous Set of Gauge Transformations approach at the B3LYP/6-311+G(2d,2p) level of theory. The chemical shifts were estimated as quantum averages along the two internal coordinates in the hydrogen bond and along several vibrational levels according to the Boltzmann distribution at room temperature. Fairly good agreement between the experimental and calculated isotope effects was obtained. 1D and 2D NMR spectra of solutions of picolinic acid N-oxide and its deuterated analogue were recorded and assigned.
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Affiliation(s)
- Jernej Stare
- National Institute of Chemistry, Hajdrihova 19, SI-1000 Ljubljana, Slovenia.
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32
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Chandra AK, Zeegers-Huyskens T. Theoretical study of the symmetry of the (OH...O)- hydrogen bonds in vinyl alcohol-vinyl alcoholate systems. J Org Chem 2003; 68:3618-25. [PMID: 12713370 DOI: 10.1021/jo020735h] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The interactions between substituted vinyl alcohols and vinyl alcoholates (X = NH(2), H, F, Cl, CN) are studied at the B3LYP/6-311++G(d,p) level of theory. In a first step, the conformation of the monomers is investigated and the proton affinities (PA(A(-))) of the enolates are calculated. The enols and enolates are held together by strong (OH...O)(-) hydrogen bonds, the hydrogen bond energies ranging from 19.1 to 34.6 kcal mol(-1). The optimized O...O distances are between 2.414 and 2.549 A and the corresponding OH distances from 1.134 and 1.023 A. The other geometry parameters such as C[double bond]C or CO distances also indicate that, in the minimum energy configuration, the hydrogen bonds are characterized by a double well potential. The Mulliken charges on the different atoms of the proton donors and proton acceptors and the frequencies of the nu(OH) stretching vibrations agree with this statement. All the data indicate that the hydrogen bonds are the strongest in the homomolecular complexes. The transition state for hydrogen transfer is located with the transition barrier estimated to be about zero. Upon addition of the zero-point vibration energies to the total potential energy, the barrier vanishes. This is a characteristic feature of low-barrier hydrogen bonds (LBHBs). The hydrogen bond energies are correlated to the difference 1.5 PA(AH) - PA(A(-)). The correlation predicts different energies for homomolecular hydrogen bonds, in agreement with the theoretical calculations. Our results suggest that a PA (or pK(a)) match is not a necessary condition for forming LBHBs in agreement with recent data on the intramolecular hydrogen bond in the enol form of benzoylacetone (J. Am. Chem. Soc. 1998, 120, 12117).
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Affiliation(s)
- Asit K Chandra
- Birla Institute of Technology and Science, Pilani 333 031, Rajasthan, India
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33
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Salnikov GE, Genaev AM, Mamatyuk VI. Unusually strong temperature dependence of 13C chemical shifts and degenerate conformational exchange in cyclobutenyl carbocations. MENDELEEV COMMUNICATIONS 2003. [DOI: 10.1070/mc2003v013n02abeh001702] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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34
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Westler WM, Weinhold F, Markley JL. Quantum chemical calculations on structural models of the catalytic site of chymotrypsin: comparison of calculated results with experimental data from NMR spectroscopy. J Am Chem Soc 2002; 124:14373-81. [PMID: 12452711 DOI: 10.1021/ja027735j] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Hybrid density functional quantum mechanical calculations were used to study the strength of the hydrogen bond between His(57) N(delta)(1) and Asp(102) O(delta)(1) in chymotrypsin and how it changes along the reaction coordinate. Comparison of experimental shifts with the results of chemical shift calculations on a variety of small molecules, including species containing very strong hydrogen bonds, has validated the overall approach and provided the means for calibrating and correcting the calculated values. Models of the active site of chymotrypsin in its resting state and tetrahedral intermediate state were derived from high-resolution X-ray structures. The distance between His(57) N(delta)(1) and Asp(102) O(delta)(1) in each model was varied between 2.77 A (weak hydrogen bond) and 2.50 A (extremely strong hydrogen bond), and the one-dimensional potential energy surface of the hydrogen-bonded proton (or deuteron/triton) was determined. The zero-point energy, probability distribution, and chemical shift were determined for each distance. Calculated values for NMR chemical shifts, NMR chemical shift differences between (1)H and (3)H, and (2)H/(1)H fractionation factors were compared with published experimental values. Energies provided by the calculations indicated that the hydrogen bond between His(57) N(delta)(1) and Asp(102) O(delta)(1) in the chymotrypsin active site increases in strength by 11 kcal mol(-)(1) in going from the resting state of the enzyme to the tetrahedral intermediate state. This result confirms the hypothesis that the strengthened hydrogen bond plays an important role in lowering the energy of the transition state and, hence, in the catalytic efficiency of the enzyme. Models of the transition state that best fit the experimental data are consistent with a "strong" hydrogen bond between His(57) N(delta)(1) and Asp(102) O(delta)(1) but apparently not a "low-barrier" or "very strong" hydrogen bond.
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Affiliation(s)
- William M Westler
- National Magnetic Resonance Facility at Madison, Department of Biochemistry, and Theoretical Chemistry Institute, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA.
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35
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Sanz P, Yáñez M, Mó O. Competition between X···H···Y Intramolecular Hydrogen Bonds and X····Y (X = O, S, and Y = Se, Te) Chalcogen−Chalcogen Interactions. J Phys Chem A 2002. [DOI: 10.1021/jp0143645] [Citation(s) in RCA: 119] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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36
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Barich DH, Nicholas JB, Haw JF. Gauge-Including Atomic Orbital Proton Chemical Shifts of Strong Hydrogen Bonds: The Importance of Electron Correlation. J Phys Chem A 2001. [DOI: 10.1021/jp004118d] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Dewey H. Barich
- Department of Chemistry, Texas A&M University, P.O. Box 30012, College Station, Texas 77842-3012, Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, Washington 99352, and Loker Hydrocarbon Research Institute and Department of Chemistry, University of Southern California, University Park, Los Angeles, California 90089-1661
| | - John B. Nicholas
- Department of Chemistry, Texas A&M University, P.O. Box 30012, College Station, Texas 77842-3012, Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, Washington 99352, and Loker Hydrocarbon Research Institute and Department of Chemistry, University of Southern California, University Park, Los Angeles, California 90089-1661
| | - James F. Haw
- Department of Chemistry, Texas A&M University, P.O. Box 30012, College Station, Texas 77842-3012, Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, Washington 99352, and Loker Hydrocarbon Research Institute and Department of Chemistry, University of Southern California, University Park, Los Angeles, California 90089-1661
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37
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Garcia-Viloca M, González-Lafont A, Lluch JM. The (1)H NMR chemical shift for the hydroxy proton of 4-(dimethylamino)-2'-hydroxychalcone in chloroform: a theoretical approach to its inverse dependence on the temperature. Org Lett 2001; 3:589-92. [PMID: 11178832 DOI: 10.1021/ol0069958] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
[reaction: see text] The inverse dependence of the chemical shift on the temperature experimentally found for the phenolic proton of 4-(dimethylamino)-2'-hydroxychalcone (DMAHC) is theoretically studied. As the temperature decreases, the solvent dielectric constant epsilon increases and the zwitterionic resonance form is more stabilized. Electronic calculations at the DFT level of theory were performed by immersing the solute DMAHC in chloroform cavities of different epsilon values. The values of the calculated chemical shifts for DMAHC as a function of epsilon show that the growing contribution of the zwitterionic structure justifies the experimental results.
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Affiliation(s)
- M Garcia-Viloca
- Departament de Química, Universitat Autònoma de Barcelona, 08193 Bellaterra (Barcelona), Spain
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38
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Garcia-Viloca M, Lluch JM. A QM/MM study of the racemization of vinylglycolate catalyzed by mandelate racemase enzyme. J Am Chem Soc 2001; 123:709-21. [PMID: 11456585 DOI: 10.1021/ja002879o] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The experimentally postulated mechanism for the interconversion between (S)-vinylglycolate and (R)-vinylglycolate catalyzed by mandelate racemase enzyme consists of a two-step quite symmetric process through a dianionic enolic intermediate that is formed after the abstraction of the alpha-proton of vinylglycolate by a basic enzymatic residue and is then reprotonated by another residue. The challenging problem behind this reaction is how the enzyme manages to stabilize such an intermediate, that is, how it lowers enough the high pK(a) of the alpha-proton for the reaction to take place. The QM/MM simulations performed in this paper indicate that catalysis is based on the stabilization of the negative charge developed on the substrate along the reaction. We have identified three different reaction mechanisms starting from different quasi-degenerate structures of the substrate-enzyme complex. In two of them the stabilizing role is done by means of a catalytic proton transfer that avoids the formation of a dianionic intermediate, and they involve six steps instead of the two experimentally proposed. On the contrary, the third mechanism passes through a dianionic species stabilized by the concerted approach of a protonated enzymatic residue during the proton abstraction. The potential energy barriers theoretically found along these mechanisms are qualitatively in good agreement with the experimental free energy barriers determined for racemization of vinylglycolate and mandelate. The theoretical study of the effect of the mutation of Glu317 by Gln317 in the kinetics of the reaction reveals the important role in the catalysis of the hydrogen bond formed by Glu317 in the native enzyme, as only one of the mechanisms, the slower one, is able to produce the racemization in the active site of the mutant. However, we have found that this hydrogen bond is not an LBHB within our model.
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Affiliation(s)
- M Garcia-Viloca
- Contribution from the Departament de Química, Universitat Autònoma de Barcelona, 08193 Bellaterra (Barcelona), Spain
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39
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Enzymes. Biochemistry 2001. [DOI: 10.1016/b978-012492543-4/50012-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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40
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Dannenberg JJ, Paraskevas LR, Sharma V. How Do Strong Hydrogen Bonds Affect the Acidities of Carbon Acids? An ab Initio Molecular Orbital Study. J Phys Chem A 2000. [DOI: 10.1021/jp994259j] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- J. J. Dannenberg
- Department of Chemistry, City University of New York, Hunter College and The Graduate School, 695 Park Avenue, New York, New York 10021
| | - Lilly-Rose Paraskevas
- Department of Chemistry, City University of New York, Hunter College and The Graduate School, 695 Park Avenue, New York, New York 10021
| | - Vanita Sharma
- Department of Chemistry, City University of New York, Hunter College and The Graduate School, 695 Park Avenue, New York, New York 10021
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41
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Asaro F, Liguori L, Pellizer G. Exceptional Deshielding of59Co Caused by Deuteration of the Hydrogen Bonds in Cobaloximes. Angew Chem Int Ed Engl 2000. [DOI: 10.1002/1521-3757(20000602)112:11<2008::aid-ange2008>3.0.co;2-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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42
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Affiliation(s)
- V L Schramm
- Department of Biochemistry, Albert Einstein College of Medicine, Bronx, New York 10461, USA
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43
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Garcia-Viloca M, González-Lafont À, Lluch JM. Asymmetry of the Hydrogen Bond of Hydrogen Phthalate Anion in Solution. A QM/MM Study. J Am Chem Soc 1999. [DOI: 10.1021/ja9918831] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Mireia Garcia-Viloca
- Contribution from the Departament de Química, Universitat Autònoma de Barcelona, 08193 Bellaterra (Barcelona), Spain
| | - Àngels González-Lafont
- Contribution from the Departament de Química, Universitat Autònoma de Barcelona, 08193 Bellaterra (Barcelona), Spain
| | - José M. Lluch
- Contribution from the Departament de Química, Universitat Autònoma de Barcelona, 08193 Bellaterra (Barcelona), Spain
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44
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Wachter-Jurcsak N, Detmer CA. VT 1H NMR Investigations of Resonance-Assisted Intramolecular Hydrogen Bonding in 4-(Dimethylamino)-2‘-hydroxychalcone. Org Lett 1999; 1:795-8. [PMID: 16118885 DOI: 10.1021/ol990770j] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
[reaction: see text] Resonance-assisted intramolecular hydrogen bonding in both polar aprotic and nonpolar solutions of 4-(dimethylamino)-2'-hydroxychalcone (DMAHC) has been investigated by variable-temperature proton NMR spectroscopy. In both nonpolar and polar solvents, the signal for the phenolic hydrogen moves downfield as the temperature is lowered. In each solvent system studied, a linear relationship between chemical shift and temperature was observed.
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Affiliation(s)
- N Wachter-Jurcsak
- Department of Chemistry, Hofstra University, Hempstead, New York 11549, USA.
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45
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Zeegers-Huyskens T. Are the Enol-Enolate Hydrogen Bonds at Matched PA Really Symmetrical? J Org Chem 1999; 64:4946-4948. [PMID: 11674577 DOI: 10.1021/jo982395z] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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46
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Leticia González,, Mó O, Yáñez M. Substituent Effects on the Strength of the Intramolecular Hydrogen Bond of Thiomalonaldehyde. J Org Chem 1999. [DOI: 10.1021/jo981982h] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Leticia González,
- Departamento de Química, C-9, Universidad Autónoma de Madrid, Cantoblanco, 28049-Madrid, Spain
| | - Otilia Mó
- Departamento de Química, C-9, Universidad Autónoma de Madrid, Cantoblanco, 28049-Madrid, Spain
| | - Manuel Yáñez
- Departamento de Química, C-9, Universidad Autónoma de Madrid, Cantoblanco, 28049-Madrid, Spain
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