PHYSICAL CHEMISTRY CHEMICAL PHYSICS
·
2011
·Vol. 13
·期 32
·14542-14549
·
IF 3.454
Kelei Zhuo,Yujuan Chen,Jing Chen,Guangyue Bai,Jianji Wang
Extensive applications of ionic liquids (ILs) may result in their accumulation in the ecological environment and organisms. Although ILs are popularly called “green solvents”, their toxicity, in fact, has been exhibited. Therefore the interaction of ILs with biomolecules is a cutting-edge research subject. Herein, the interactions of 1-butyl-3-methylimidazolium carboxylate ionic liquids ([C4mim][HCOO], [C4mim][CH3COO] and [C4mim][CH3CH2COO]) with glucose in water were studied for their volumetric properties, viscosity, conductivity and NMR spectra. Limiting apparent molar volumes (V0Φ,IL), viscosity B-coefficients, limiting molar conductivities (Λ0) and Walden products (Λ0η0) were evaluated for the ILs in glucose + water solutions. Volumetric interaction parameters were also obtained from the transfer volumes of the ionic liquids. The contributions of the solvent properties (B1) and the ionic liquid–solvent interactions (B2) to the B-coefficient were extracted, together with molar activation energies (Δμ0≠IL) of the ionic liquids for viscous flow of the aqueous glucose + IL solution. In addition, the 13C and 1H NMR spectra of methyl β-D-glucopyranoside and ILs in β-D-glucopyranoside + IL + D2O were studied. The NMR results show that no special and strong interactions were observed between glucopyranoside and the ILs. However, it was confirmed that the H2 on the imidazolium ring has more activity (acidity) than atoms H4 and H5. The macro-properties and their changes were also discussed in terms of the size, structure and solvation of the ILs and glucose.
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TETRAHEDRON
·
2017
·
IF 2.651
Zhenyu Tian,Kun Meng,Yanhong Shi,Naixia Zhang,Xuehui Liu,Hongwei Jin,Yongmin Zhang,Lihe Zhang,Demin Zhou,Sulong Xiao
A newly synthesized hexavalent oleanolic acid/per- O -methylated α -cyclodextrin conjugate shows significant differences in NMR spectra with previously synthesized analogs. Characterization of the product by 1 H NMR, 13 C NMR, COSY, HSQC , HMBC , TOCSY , NOE, and ROESY experiments were performed. Detailed investigations revealed that the compound has two conformations in solution and the ratio of them was 1:1. Further variable-temperature NMR study revealed that the two conformations were stable at temperature range of 273–323 K in CDCl 3 solution.
研究领域:
有机化学
·
药物化学
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EUROPEAN FOOD RESEARCH AND TECHNOLOGY
·
2016
·Vol. 242
·期 7
·1177-1185
·
IF 1.433
Ma Fumin,Dang Yali,Xu Shiying
In this study, water-extractable arabinoxylan, WEAX, of wheat was isolated and mixed with gluten to observe small and large strain behavior and microscopic structure of the mixtures. The results showed that WEAX improves the viscoelasticity of gluten and makes the microscopic structure of gluten less compact. Free sulfhydryl, fluorescence anisotropy and CP/MAS 13 C NMR measurements were used to gain a better understanding of the interactions between WEAX and gluten proteins of wheat. It was demonstrated that when gluten was mixed with WEAX, the free –SH of gluten proteins cross-linked to each other or to WEAX. The cross-linking happened mainly to LMW-GS. It was shown from the fluorescence anisotropy that the conformation of glutenin was more greatly influenced by WEAX than gliadin because of the difference in their molecular conformation. In addition, it was found in this study that tyrosine groups of glutenin also played an important role in the interactions between WEAX and gluten.
研究领域:
食品科学
·
分子生物学
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INDUSTRIAL CROPS AND PRODUCTS
·
2024
·
IF 5.6
Jiayu Xie,Xuran Jin,Hong Cheng,Wei Chen,Wancheng Yu,Linlin Wang
Glycerol has been proved to be an effective plasticizer for polyvinyl alcohol (PVA), which can significantly increase PVA’s processability and ductility, whose molecular origin remains unclear. In current study, the physical structure and chain dynamics of polyol plasticized PVA were studied in detail, including ethylene glycol , glycerol, erythritol , xylitol , and sorbitol under the same addition level. The glycerol plasticized PVA exhibits the most significant reduction in Young’s modulus, enhanced superior toughness, and the lowest melting temperature (195 °C) as compared with other polyols. The molecular mechanism was elucidated through comprehensive analysis, with a particular focus on solid state NMR (SS NMR) results. The physical structure was first elucidated by the Small Angle X-ray Scattering (SAXS) and Wide Angle X-ray Scattering (WAXS). The crystallinity of the glycerol plasticized PVA was the lowest 29 % by WAXS and the thickness of the amorphous layer was the largest 7.76 nm by SAXS among different plasticized PVA films. This suggests the significant influence of glycerol on structure change of PVA. The molecular dynamics information was further accessed by Low Field Nuclear Magnetic Resonance (LF NMR), where two key features are obtained: i) Different dynamics dimensionality. The 1 H spin diffusion NMR was used to check the dimensionality from the aspect of chain dynamics. Compared with other plasticizers, LF NMR result shows that glycerol plasticized PVA has a two-dimensional (2D) structure; ii) Chain dynamics heterogeneity in the interphase . With respect to the chain dynamics heterogeneity in the interphase, the glycerol plasticized PVA shows the most heterogeneous dynamics, with the lowest ratio of the rigid amorphous fraction (RAF) of 0.507 in the interphase. Current study provides a versatile analytical strategy to quantify the plasticizing effect.
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CARBOHYDRATE POLYMERS
·
2026
·
IF 13.2
Minghao Shi,Jiewen Fu,Xiang Shi,Xusheng Lv,Yonghong Liu,Qingxia Yuan,Longyan Zhao
Chemical sulfation of well-defined, low-molecular-weight, non-animal polysaccharides represents a potential approach to anticoagulants that potently inhibit the intrinsic tenase complex (iFXase) while causing fewer side effects, notably a low risk of bleeding. From Lessonia flavicans , we isolated a 5.5-kDa laminarin (LFP0) with a (1 → 3)-β-D-glucan core and trace branching. LFP0 was sulfated under anhydrous and short-time conditions to afford four derivatives (LFP0-S1–S4) with degrees of substitution (DS, 0.1–1.5), molecular weights (6.2–10.9 kDa), and sulfate contents (5.8%–46.2%). Physicochemical analysis and 2D NMR confirmed an intact structure with predominant C-6- O -sulfation, then C-2/C-4 sulfation. The sulfated laminarins prolonged APTT in proportion to DS and left PT unaltered. LFP0-S4, with high FIXa affinity, surpassed LMWH in iFXase inhibition by 80.6% but showed only 58.7% of its TT prolongation, indicating higher selectivity for intrinsic-pathway inhibition. In mice, LFP0-S4 exhibited potent antithrombotic activity without obvious bleeding risk, and showed no toxicity at doses up to 2000 mg/kg. These findings position L. flavicans laminarin as a promising structural blueprint for developing intrinsically targeted anticoagulants and warrant further investigation of its pharmacological and toxicological profiles.
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JOURNAL OF MOLECULAR LIQUIDS
·
2025
·
IF 5.2
Chengping Deng,Teng He,Xingcai Yu,Haiyang He,Yuqiang Mao,Han Wang,Dianwen Liu
The wettability has an important effect on the floatability of carbon particles (low-rank coal and fly ash), including surface and pore wettability. The pore wettability of the porous carbon particles is a dynamic process and can further affect their surface wettability. In order to enhance the flotation performance of porous carbon particles, the roles of n-hexadecane on their pore wetting kinetics, chemical properties and surface hydrophobicity were studied by six classic flotation kinetic models, 1 H low-field nuclear magnetic resonance ( 1 H LF-NMR), fourier transform infrared spectroscopy (FTIR), contact angle and flotation experiments. 1 H LF-NMR could accurately characterize the volume of pure water and n-hexadecane in the pores of the particles. The wetting processes of total pores in the particles wetted by pure water and n-hexadecane both fitted the first-order model with rectangular distribution. However, the pore wetting degree and rate of the particles in n-hexadecane at the same time were all smaller than those in pure water. A larger number of methyl and methylene contained in n-hexadecane could physically adsorbed to the particles by the van der Waals forces, resulting in an increase of surface hydrophobicity. Therefore, the good flotation performance of the porous particles was achieved by non-polar liquid n-hexadecane. This work attempts to provide a new inspiration for the efficient flotation of porous carbon particles.
研究领域:
矿物加工
·
表面化学
·
煤浮选
·
低场核磁共振
·
胶体与界面科学
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Nano Energy
·
2020
·
IF 16.602
Zhenjing Jiang,Tongyao Zhao,Jinjun Ren,Yanfei Zhang,Yuanzheng Yue
Recently it has been demonstrated that the electrochemical performances of semiconducting amorphous anodes for Li-ion batteries (LIBs) can be greatly enhanced by the discharging/charging induced nanocrystals . However, the structural origin of those nano-domains remains elusive, although it is critically important for designing superior glass anodes for LIBs. In this work, we probe the local structural evolution in a glass anode for LIBs during cycles by means of the state-of-the-art solid-state nuclear magnetic resonance (SSNMR). The structural evolution is manifested as the disassociation of the structural network into isolated units, followed by formation of different types of nano-domains with a high degree of order. These domains are highly favorable for rate capability and long-term cycling stability. From SSNMR and electrochemical characterizations, we have obtained a clear picture about the detailed redox reactions . These findings provide a chemical principle that is helpful for designing the stable glass electrodes for high-performance LiBs.
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POWDER TECHNOLOGY
·
2021
·
IF 5.134
Wencheng Xia,Yuqiang Mao,Guangyuan Xie,Yaoli Peng
The filling of pores by flotation-reagent-contained water plays an important role in porous mineral flotation . This paper studied the role of sodium oleate (NaOL, a commonly used flotation reagent) solution in the in-situ wetting process of pores of porous active carbon using 1 H LF-NMR, FTIR as well as contact angle measurements. The floatability of active carbon particles wetted by NaOL solutions was evaluated by particles-bubble attachment measurements. The pore wetting percentage decreased as the NaOL concentration increased. The variation trend in pore wetting percentage by NaOL solutions was from fast to slow. Increasing the NaOL concentration contributed to achieve a lower pore wetting percentage as well as rate. The NaOL solution with a high concentration significantly improved the hydrophobicity of the sample, which further prevents the pore wetting process.
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Journal of Physical Chemistry C
·
2019
·
IF 4.309
Xuyang Zhang,Lili Hu,Jinjun Ren
Oxyfluoride glasses in the systems (55 – x)SiO2–(15 + x – z)Al2O3–zLa2O3–10CaO–20CaF2–yErF3 (x = 0, 5, 10, 15; y = 0.5, 1, 1.5; z = 0, 2, 5 mol %) were prepared by conventional melt-quenching method and afterward heated to synthesize transparent glass ceramics containing CaF2 nanocrystals. The local structures of glasses and glass ceramics were characterized by advanced one- and two-dimensional solid-state nuclear magnetic resonance (SSNMR) techniques. La3+ ions were investigated as the diamagnetic mimics for paramagnetic rare-earth ions (REIs) in local structure. The bond connectivities between F– ions and positive ions were probed by 19F magic angle spinning (MAS) NMR spectra and 19F {27Al} double-resonance techniques. F– ions have bond connectivities with Ca2+, La3+, and Al3+ ions, respectively. Ca2+ ions have comparable competition ability in capturing F– ions with La3+ ions, but stronger than Al3+ ions. Multiple F–Al linkages exist in the glasses. 19F static spin echo decay results indicate that F– ions aggregate around Ca2+ ions forming F–Ca linkages-enriched microregions, which form the precursors of CaF2 nanocrystals. However, both La3+ and Al3+ ions can disperse the distribution of F– ions around Ca2+ ions and consequently suppress the crystallization of CaF2. 139La wideband uniform-rate smooth truncation QCPMG (WURST-QCPMG) spectra and the paramagnetic effects of Er3+ on the NMR spectra were measured to reveal the distribution of REIs. The average local environments of most REIs have no significant change during the crystallization of CaF2. Only partial REIs have entered CaF2 nanocrystals after the crystallization, which results in the intensive Er3+ upconversion luminescence. The glass structural evolution during the crystallization is investigated by the evolution of the 19F, 27Al, 29Si, and 139La NMR spectra with the heat treatment conditions. On the basis of the comprehensive glass structure study at the atomic level, the microcrystallization mechanisms of the glasses are revealed.
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Journal of Energy Chemistry
·
2024
·
IF 14
Fan Li,Tiantian Dong,Yi Ji,Lixin Liang,Kuizhi Chen,Huanrui Zhang,Guanglei Cui,Guangjin Hou
Solid polymer electrolytes (SPEs) have become increasingly important in advanced lithium-ion batteries (LIBs) due to their improved safety and mechanical properties compared to organic liquid electrolytes. Cross-linked polymers have the potential to further improve the mechanical property without trading off Li-ion conductivity. In this study, focusing on a recently developed cross-linked SPE, i.e., the one based on poly(vinylene carbonate)-poly(ethylene oxide) cross-linked network (PVCN), we used solid-state nuclear magnetic resonance (NMR) techniques to investigate the fundamental interaction between the chain segments and Li ions, as well as the lithium-ion motion. By utilizing homonuclear/heteronuclear correlation, CP (cross-polarization) kinetics, and spin–lattice relaxation experiments, etc., we revealed the structural characteristics and their relations to lithium-ion mobilities. It is found that the network formation prevents poly(ethylene oxide) chains from crystallization, which could create sufficient space for segmental tumbling and Li-ion conduction. As such, the mechanical property is greatly improved with even higher Li-ion mobilities compared to the poly(vinylene carbonate) or poly(ethylene oxide) based SPE analogues.
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JOURNAL OF FOOD PROCESS ENGINEERING
·
2026
·Vol. 49
·期 5
·e70517
·
IF 3.5
Fengping Pang,Wanbing Cheng,Mingyang Liao,Chengtao Nong,Lisha Ye,Ligao Deng,Jianbin Li
To explore the changes in flavor compounds during the hydrolysis of sulfited sugarcane syrup (SS) by sucrase. This study characterized non-volatile organic compounds (NVOCs) via nuclear magnetic resonance (NMR) spectroscopy. Volatile organic compounds (VOCs) were characterized using gas chromatography–mass spectrometry (GC–MS) and gas chromatography–ion mobility spectrometry (GC–IMS). About 14 NVOCs were identified, with 7 NVOCs, including sucrose, fructose, α-glucose, and β-glucose, showing significant dynamic changes. About 80 VOCs were identified by GC–MS. Pyrazines were the predominant compound in the SS, whereas pyrazines and acids became the major components in the hydrolyzed SS. Enzymatic hydrolysis significantly increased the overall VOCs content, particularly acids and aldehydes, while reducing unpleasant S-containing compounds. Orthogonal partial least squares-discriminant analysis (OPLS-DA) revealed that 30 differential VOCs (Variable Importance in Projection, VIP > 1) served as markers for distinguishing among the five syrup samples. Furthermore, three key differential aroma compounds (2,5-dimethylpyrazine, dimethyl sulfide, and β-damascenone) were identified by VIP and Odor Activity Value (OAV). Additionally, we detected 56 VOCs by GC–IMS. The fingerprint profiles and OPLS-DA confirmed significant differences in VOCs during enzymatic hydrolysis. Overall, these findings offer new insights into the flavor chemistry of SS during enzymatic hydrolysis and a theoretical basis for optimizing flavored syrup processing.
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JOURNAL OF MOLECULAR STRUCTURE
·
2012
·
IF 1.634
Fu Liu,Zhongbo Wei,Liansheng Wang,Zunyao Wang
4,4′-Dihydroxydiphenyl ether and 4,4′-oxybis(1-methoxybenzene) are synthesized. Experimental and theoretical studies on molecular structure, infrared spectra (IR), Raman spectra and nuclear magnetic resonance ( 1 H NMR) chemical shifts of the two synthesized compounds have been worked out. All the theoretical results, which are obtained with B3LYP/6-311G(d,p) method by using the Gaussian 09 program, have been applied to simulate molecular structure, infrared, Raman and NMR spectra of the compounds. The compared results reveal that the calculated geometric parameters match well with experimental values; the scaled theoretical vibrational frequencies are in good accordance with observed spectra; and computational chemical shifts are consistent with the experimental values in most part, except for some minor deviations. These great coincidences prove that the computational method B3LYP/6-311G(d,p) can be used to predict the properties of other similar materials where it is difficult to arrive at experimental results.
研究领域:
化学
·
理论计算化学
·
光谱学
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