Journal of Physical Chemistry Letters
·
2021
·
IF 6.475
Ke Gong,Zhengmao Liu,Lixin Liang,Zhenchao Zhao,Meiling Guo,Xuebin Liu,Xiuwen Han,Xinhe Bao,Guangjin Hou
Herein, utilizing acetonitrile as the probe molecule, the acidity and host–guest interactions of H-mordenite (H-MOR) zeolites are investigated comprehensively by solid-state NMR spectroscopy and theoretical calculation. The locations and local configurations of Brønsted acid sites (BASs) in H-MOR are revealed by multinuclear and multidimensional NMR experiments with adsorption/coadsorption of acetonitrile (CD3CN) and trimethylphosphine (TMP). Moreover, the confinement effect of dual pores in MOR has been characterized via the quantitative determination of host–guest interactions between CH3CN and BASs. The 1H–15N dipolar measurement results and DFT calculations demonstrate that there are two kinds of acetonitrile molecules adsorbed in 12-membered ring (12MR) main channels with distinct mobility, where acetonitrile undergoes either partially restricted or highly flexible motion in the time scale of nanoseconds to microseconds. These two types of acetonitrile can exchange with temperature rising. In contrast, the mobility of acetonitrile in 8-membered ring (8MR) channels is very restricted due to the confinement of the framework.
研究领域:
材料科学
·
催化化学
·
物理化学
·
固体核磁共振波谱学
·
沸石化学
✓ 已验证
DOI
高影响因子
Journal of Physical Chemistry C
·
2016
·
IF 4.509
Ruili Zhang,Marcos de Oliveira,Zaiyang Wang,Roger Gomes Fernandes,Andrea S. S. de Camargo,Jinjun Ren,Long Zhang,Hellmut Eckert
The structure of glasses in the systems (100 – x)B2O3–xPbF2 (x = 30, 40, and 50) and 50B2O3–(50 – x)PbO–xPbF2 (x = 5, 10, 15, 20, 25, 30, 35, 40, and 45) has been studied by solid state NMR and EPR spectroscopies. On the basis of 11B and 19F high resolution solid state NMR as well as on 11B/19F double resonance results, we develop a quantitative structural description on the atomic scale. 19F NMR results indicate a systematic dependence of the fluoride speciation on PbF2 content: At low x-values, F– ions are predominantly found on BO3/2F– units, whereas, at higher x-values, fluoride tends to be sequestrated into amorphous domains rich in PbF2. In addition, both pulsed EPR studies of Yb3+ doped glasses and photophysical studies of Eu3+ doped samples indicate a mixed fluoride/borate coordination of the rare-earth ions and the absence of nanophase segregation effects.
研究领域:
材料科学
·
玻璃化学
·
光谱学
·
固体物理
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无机化学
✓ 已验证
DOI
高影响因子
CHEMICAL ENGINEERING SCIENCE
·
2012
·
IF 2.431
Yingjie Xu,Wu Qian,Qiongqiong Gao,Haoran Li
The 1 H NMR chemical shifts of alcohol+hydrocarbon systems over the whole concentration range at 298.15 K were measured. Based on the concept of local composition (LC), the concentration-dependent 1 H NMR chemical shift data of the OH and CH groups for 13 alcohol+hydrocarbon systems were correlated with only one energy parameter, respectively. Using the parameters obtained from the spectra alone, the isothermal and isobaric vapor–liquid equilibria (VLE) data of the above-mentioned alcohol+hydrocarbon systems were predicted with satisfactory results. By this way, the spectroscopic information can be used to predict VLE data of alcohol+hydrocarbon systems directly.
研究领域:
化学
·
物理化学
✓ 已验证
产品关联
DOI
高影响因子
Green Energy & Environment
·
2020
·
IF 6.395
Pengfei Liu,Christian Marcus Pedersen,Jiaojiao Zhang,Rui Liu,Zhenzhou Zhang,Xianglin Hou,Yingxiong Wang
Ternary deep eutectic solvents (TDESs) comprising choline chloride (ChCl), glycerol and l -arginine were synthesized as catalysts and solvents for the conversion of d -glucosamine (GlcNH 2 ) into deoxyfructosazine (DOF). The interactions between these three components in the prepared TDESs were studied by 1 H-, 35 Cl-NMR spectra and 1 H diffusion-ordered spectroscopy (DOSY) measurements. The chemical shift changes of active hydrogen in the 1 H-NMR spectra of TDES system and widening of signals in the 35 Cl-NMR spectra confirmed the hydrogen bonding interaction between the components, which was further supported by the decrease of diffusion coefficients ( D ) of the TDES components according to 1 H DOSY measurements. The influences of reaction temperature and l -arginine content in the TDESs on the yield of DOF were also studied. The experimental results have shown that when the molar ratio of ChCl, glycerol, and l -arginine was 1:2:0.1, DOF was the major product with a yield of 22.6% at 90 °C for 120 min. The chemical shift titration indicated that the carboxyl group of l -arginine in the TDES is the catalytical active site, so the mechanism of the catalytic reaction between GlcNH 2 and the TDES was proposed. Moreover, a reaction intermediate, dihydrofructosazine, was identified in the self-condensation reaction of GlcNH 2 by an in situ 1 H NMR technique.
研究领域:
生物化学
·
催化化学
✓ 已验证
产品关联
DOI
高影响因子
MICROPOROUS AND MESOPOROUS MATERIALS
·
2020
·
IF 4.551
Jiaqi Ma,Xiao-Bin Fu,Yuquan Li,Tian Xia,Likun Pan,Ye-Feng Yao
This study investigates the locations and interactions of adsorbed water molecules within a porous COF material, TpPa-1. The TpPa-1 samples include the as-synthesized powder samples and the samples first subjected to compression at high pressure and then ground into a powder form. The investigation applies a variety of advanced solid-state NMR techniques. The results indicate that the adsorbed water molecules in the as-synthesized and compressed samples can exist in different locations and bonding states. Here, the adsorbed water molecules in the as-synthesized samples are found to be mainly located in the pore spaces and interact only loosely with the chemical groups of the material. In contrast, a proportion of the water molecules in the compressed samples enter into the interstices between the layers and interact with the amino groups and the carbonyl groups of the material. The relocation of the water molecules in the compressed samples provides a plausible explanation for the molecular origin of the water adsorption capability of TpPa-1. In addition, the revealed weak interactions between the water molecules and the chemical groups of TpPa-1 are correlated with the molecular origin of the high water permeance.
研究领域:
材料科学
·
化学
✓ 已验证
产品关联
DOI
高影响因子
ANALYTICAL SCIENCES
·
2021
·Vol. 37
·期 10
·1413-1418
·
IF 2.081
Hua ZHAO,Xiaohui WANG,Yuli ZHANG,Xiaowan HUANG,Yaling JIANG,Huan MA,Li AN,Xujin WU,Qiang WANG
Saikosaponin a and saikosaponin d are used as chemical standards for the quality evaluation of Bupleurum chinense DC. by the high-performance liquid chromatography method in current Chinese Pharmacopoeia. However, other saikosaponins, such as saikosaponin c and saikosaponin b2, also possess pharmaceutical activity, but are not used as chemical standards. In this study, a quantitative proton nuclear magnetic resonance (1H NMR) method was developed to determine the total mass percentage (mg/g) of SSa, SSb1, SSb2 and SSd in B. chinense DC., using the H-24 (δH 0.71) signal. Furthermore, the molality (mol/kg) of type I saikosaponins (epoxy-ether structure) was also determined by quantitative 1H NMR in the area of H-11 (δH 5.95) for a more accurate quality evaluation. Validation of the method confirmed that it has acceptable selectivity, precision, stability, and repeatability. The results indicated that this method has the potential to be a reliable method for the quantification of saikosaponins in Bupleurum scorzonerifolium Willd., vinegar baked B. chinense DC. and B. scorzonerifolium Willd., Chaihu Koufuye (oral liquid of Chaihu).
研究领域:
药学化学
·
分析化学
·
生药学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Green Energy & Environment
·
2022
·
IF 12.781
Qi Zhao,Christian Marcus Pedersen,Jiamin Wang,Rui Liu,Yuanli Zhang,Xiuyin Yan,Zhenzhou Zhang,Xianglin Hou,Yingxiong Wang
The component analysis and structure characterization of complex mixtures of biomass conversion remain a challenging work. Hence, developing effective and easy to use techniques is necessary. Diffusion-ordered NMR spectroscopy (DOSY) is a non-selective and non-invasive method capable of achieving pseudo-separation and structure assignments of individual compounds from biomass mixtures by providing diffusion coefficients ( D ) of the components. However, the conventional 1 H DOSY NMR is limited by crowded resonances when analyzing complex mixtures containing similar chemical structure resulting in similar coefficient. Herein we describe the application of an advanced diffusion NMR method, Pure Shift Yielded by CHirp Excitation DOSY (PSYCHE-iDOSY), which can record high-resolution signal diffusion spectra efficiently separating compounds in model and genuine mixture samples from cellulose, hemicellulose and lignin. Complicated sets of isomers ( d -glucose/ d -fructose/ d -mannose and 1,2-/1,5-pentadiol), homologous compounds (ethylene glycol and 1,2-propylene glycol), model compounds of lignin, and a genuine reaction system (furfuryl alcohol hydrogenolysis with ring opening) were successfully separated in the diffusion dimension. The results show that the ultrahigh-resolution DOSY technique is capable of detecting and pseudo-separating the mixture components of C 5 /C 6 sugar conversion products and its derivative hydrogenation/hydrogenolysis from lignocellulose biomass.
研究领域:
分析化学
·
生物质能
·
催化化学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF APPLIED MICROBIOLOGY
·
2025
·
IF 3.2
Zhang Chuhan,Qin Lijun
AimsTo determine the optimum conditions for extracting Eucommia ulmoides gum (EUG) from Eucommia ulmoides leaves during fermentation by Coprinellus disseminatus. At the same time, the EUG characteristics were characterized.Methods and resultsThe ability of C. disseminatus to secrete degrading enzymes, including enzyme activity and lignocellulose content, was observed by culturing C. disseminatus on a medium with different formulations. Based on the optimal formula, the fermentation conditions were determined by an orthogonal test and EUG was extracted. After that, the characteristic parameters of EUG were determined by FT-IR, 1H-NMR, SEM, POM, DSC, XRD and GPC. The results showed that the lignin and hemicellulose contents in Eucommia leaves decreased significantly with the increase of fermentation days, and C. disseminatus mediated fermentation had an obvious damage effect on the tissue of Eucommia leaves. At the same time, At the same time, xylan can be used as an initiator to induce the expression of degradation-related enzymes. The extraction yield of EUG from Eucommia ulmoides leaves after fermentation was 3.06%, which was significantly improved. The optimum fermentation conditions were 4% inoculum, 28°C fermentation temperature, and pH = 5. The results of infrared FT-IR and 1H-NMR showed that the extract had typical characteristics of EUG, and the surface and quenching part of the EUG were smooth, as observed by SEM. In addition, DSC and XRD analysis show that there are two crystal types, α and β, in the crystallization process of molten EUG. The main crystallization type of EUG extracted from fermented leaves was β type.ConclusionThe ability of C. disseminatus to produce degrading enzymes can effectively improve the extraction rate of EUG under optimal fermentation process. The method can maintain the integrity of gutta-percha better. EUG has the characteristics of good crystallinity, many β crystal types and high molecular weight.
研究领域:
生物技术
·
生物化学
·
材料科学
·
植物学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
RSC Advances
·
2015
·Vol. 5
·期 16
·12007-12014
·
IF 3.84
Lingxing Zhang,Huan Zhang,Fei Gao,Huiying Peng,Yonghong Ruan,Yuanze Xu,Wengui Weng
An azobenzene derivative (F-azo-COOH) was synthesized and could be E/Z isomerized by visible light. The host–guest interaction between F-azo-COOH and cyclodextrins (CDs) in alkaline aqueous solution was studied by NMR spectroscopy for the first time. The results revealed that F-azo-COOH did not form a stable host–guest complex with α-CD. However, both trans- and cis-F-azo-COOH could form stable 1 : 1 complexes with β-CD. Most interestingly, cis-F-azo-COOH could fit the cavity of β-CD more tightly (3.0 ± 0.3 × 103 M−1) than its trans form (2.1 ± 0.2 × 103 M−1), which was completely opposite to the conventional azobenzene/β-CD system.
研究领域:
化学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
Revista Brasileira de Farmacognosia-Brazilian Journal of Pharmacognosy
·
2020
·Vol. 30
·期 1
·28-33
·
IF 1.407
Wang Cong,Zhang Pengpeng,Zhang Xiuli,Yu Mingming,Lv Zhihua
Huganning, a Chinese patent medicine, has been used in clinical practice for the treatment of hepatitis in China for more than 20 years, and its main physiologically active components are polydatin and emodin. In this study, a rapid and accurate proton nuclear magnetic resonance method for the quantification of these constituents was developed. 4-Nitrochlorobenzene was selected as an internal standard, and the signals for polydatin at δ 6.44 ppm and emodin at δ 7.54 ppm were chosen for the quantification. Validation of the method was performed in terms of specificity, precision, and stability. The results indicated that the method was precise and in line with the China Food and Drug Administration guidance. The method has been successfully applied to characterize tablets and capsules obtained from six pharmaceutical companies. This study indicated that the rapid 1 H NMR method is more suitable for the quality control of Huganning than the high-performance liquid chromatography method.
Graphical Abstract
研究领域:
药学
·
中药学
✓ 已验证
DOI
高影响因子
CEMENT & CONCRETE COMPOSITES
·
2024
·
IF 10.8
Lixiao Zhao,Pan Feng,Jinxiang Hong,Qi Liu,Guoqing Geng
Water-soluble organic admixtures (WSOAs) are widely used in cementitious materials, and may affect the porosity, but their effects on low-field nuclear magnetic resonance (LF-NMR) measurement are often overlooked. Using viscosity modifying admixture (VMA) as an example, this study demonstrates the presence of WSOAs would lead to an overestimation of porosity and a leftward shift of pore size distribution using LF-NMR. This is attributed to the formation of hydrogen bonds between polymer and water molecules, and the decreased distance between nuclear spins, respectively. A strategy is proposed to improve the accuracy of the porosity characterization by eliminating the additional effects of WSOAs in LF-NMR testing. The results show that the addition of small molecular mass non-ionic VMAs replacing mixing water (within a 20 % replacing rate) does not alter the porosity of the paste. This method can be extended to characterize the porosity of various porous materials containing WSOAs.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
ORGANIC & BIOMOLECULAR CHEMISTRY
·
2024
·
IF 2.9
Ting Jiang,Qian Zhou,Kang-Kang Yu,Shan-Yong Chen,Kun Li
N
6
-Methyladenosine (6mA) is a well-known prokaryotic DNA modification that has been shown to play epigenetic roles in eukaryotic DNA. Accurate detection and quantification of 6mA are prerequisites for molecular understanding of the impact of 6mA modification on DNA. However, the existing methods have several problems, such as high false-positive rate, time-consuming and complex operating procedures. Chemical sensors for the selective detection of 6mA modification are rarely reported in the literature. Fluorinated phenylboronic acid combined with 19F NMR analysis is an effective method for determining DNA or RNA modification. In this study, we presented a simple and fast chemical method for labelling the 6th imino group of 6mA using a boric-acid-derived probe. Besides, the trifluoromethyl group of trifluoromethyl phenylboronic acid (2a) could detect 6mA modification through 19F NMR. Combined with this sensor system, 6mA modification could be detected well and quickly in 6 types of deoxynucleoside mixtures and DNA samples. Taken together, the method developed in the current study has potential for specific detection of 6mA in biological samples.
研究领域:
生物化学
·
分子生物学
·
分析化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）