APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING
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2019
·Vol. 125
·期 9
·1-6
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IF 1.784
Zhao Tian,Dong Ming,Zhao Yi
[Fe(HB(pz) 3 ) 2 ], a well-studied spin-crossover (SCO) complex, has been entrapped in NH 2 -MIL-101(Al) metal–organic framework (MOF) via gas diffusion method. [Fe(HB(pz) 3 ) 2 ] would sublimate when temperature exceeds 100 °C, especially at low pressure. Thus, in the selected condition, [Fe(HB(pz) 3 ) 2 ] molecules can be sublimated to a gas phase and diffused into the pores of NH 2 -MIL-101(Al), which yield [Fe(HB(pz) 3 ) 2 ]@MIL-101 hybrid materials. The identity of composites, with a loading of iron complex at ~ 8 wt%, was characterized by X-ray diffraction and spectroscopic attestation. The hybrid materials demonstrate a gentle spin transition curve from 300 to 400 K, which is different from the SCO behavior of [Fe(HB(pz) 3 ) 2 ]. And for the pure [Fe(HB(pz) 3 ) 2 ] sample at 400 K, only 60% of Fe(II) is in HS, while in hybrid samples, HS state is complete. This interesting phenomenon might indicate that the spin transition in the hybrid sample can be triggered at lower temperature. The composite samples were thoroughly studied by X-ray diffraction, IR spectroscopy, atom absorption spectroscopy, nitrogen physisorption, and magnetic measurements. Thereby, a novel MOF-based material with isolated SCO units is proposed, which demonstrate a salient ‘matrix-effect’ on spin-crossover behavior of [Fe(HB(pz) 3 ) 2 ].
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高影响因子
APPLIED SURFACE SCIENCE
·
2009
·
IF 1.576
J.C. Chen,W.Q. Luo,H.D. Wang,J.M. Xiang,H.F. Jin,F. Chen,Z.W. Cai
A versatile method was developed for the chain-end functionalization of the grafted polymer chains for surface modification of nanoparticles with functionalized groups through a combination of surface-initiated atom-transfer radical polymerization (ATRP) and Huisgen [3 + 2] cycloaddition. First, the surface of SiO 2 nanoparticles was modified with poly(methyl methacrylate) (PMMA) brushes via the “grafting from” approach. The terminal bromides of PMMA-grafted SiO 2 nanoparticles were then transformed into an azide function by nucleophilic substitution. These azido-terminated PMMA brushes on the nanoparticle surface were reacted with alkyne-terminated functional end group via Huisgen [3 + 2] cycloaddition. FTIR and 1 H NMR spectra indicated quantitative transformation of the chain ends of PMMA brushes onto SiO 2 nanoparticles into the desired functional group. And, the dispersibility of the end-functional polymer-grafted SiO 2 nanoparticles was investigated with a transmission electron microscope (TEM).
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高影响因子
GREEN CHEMISTRY
·
2021
·Vol. 23
·期 6
·2352-2361
·
IF 10.182
Yuanlong Guo,Long Li,Gu Guo,Min Pei,Lihua Zhang,Haibo Xie,Hui Sun,Qiang Zheng
Recently, cellulose esters with particular functionality have obtained considerable attention as they can be used in various fields; therefore, the design and facile synthesis of cellulose esters is still a prime subject of research in this area. In this study, a novel cellulose derivative, namely cellulose-3-(2-hydroxyphenyl) propionate ester (CHP), was first prepared using cellulose and 3,4-dihydrocoumarin (DHC) in dimethylsulfoxide (DMSO)/1,8-diazabicyclo[5.4.0]undec-7-ene (DBU)/CO2, a newly developed cellulose solvent system, without adding any external catalyst. The effects of the reaction conditions on the substitution degree (DS), including DHC loading, reaction temperature and time, were systematically investigated, and the CHP with a DS of 2.35 could be prepared when the molar ratio of DHC to anhydroglucose units (AGU) was set at 6/1 at 120 °C in 3 h. The structures and thermal properties of the as-prepared CHP were fully elucidated by nuclear magnetic resonance spectroscopy (NMR), Fourier transform infrared (FT-IR) spectroscopy, differential scanning calorimetry (DSC), and thermal gravimetric analysis (TGA). The ultraviolet (UV) absorption properties and free radical scavenging ability were evaluated by UV-visible absorption spectroscopy and a well-developed 2,2-diphenyl-1-picrylhydrazyl (DPPH)-based colorimetric protocol. The CHPs were identified to have satisfactory UV absorption properties and antioxidant capacity, and the instant DPPH radical scavenging activity reached 68.1% to 100% in 30 min when 40 mM of CHP was applied at 25 °C. Kinetic studies demonstrated that the reaction followed a pseudo-first order reaction kinetic model, and the activation energy (Ea) and Arrhenius frequency factor (A) of CHP-3 to DPPH could be calculated to be 24.24 kJ mol−1 and 2.5918 s−1 by the Arrhenius equation, respectively. The cytotoxicity of the CHPs was also primary evaluated in L929 cells to identify the potential of CHPs for biomedical applications.
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高影响因子
MICROCHIMICA ACTA
·
2017
·Vol. 184
·期 7
·2325-2331
·
IF 4.58
Huang Xinan,Jiang Hong,Li Yongxin,Sang Lijia,Zhou Huipeng,Shahzad Sohail Anjum,Ibupoto Zafar Hussain,Yu Cong
A sensitive and selective luminescent nanoprobe (referred to as DEPN) is designed for the determination of Cu(II) ions. DEPN shows two emission peaks, one at 602 nm and caused by [Ru(bpy) 3 ] 2+ , the other (peaking at 500 nm) caused by silver nanoclusters (AgNCs). The luminescence of the ruthenium complex is inert and acts as the internal reference signal, while that of the AgNCs is quenched by Cu(II) ions. Under 350 nm photoexcitation, a linear relationship is found between the ratio of emission intensity (I 500 /I 602 ) and the concentration of Cu(II) ions in the 0.1–16 μM range. The detection limit of Cu(II) ions is estimated to be 50 nM. The DEPN was applied to the determination of Cu(II) ions in (spiked) water samples, and to intracellular imaging of Cu(II) in HeLa cells using confocal fluorescence microscopy.
Schematic presentation of a dual-emission photoluminescence nanoprobe for selective Cu 2+ sensing. The emission of the Ag nanoclusters (at 500 nm) is quenched by Cu 2+ , while that of the Ru(bpy) 3
2+ -doped silica nanoparticles (at 602 nm) remains unchanged and serves as a reference.
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高影响因子
LWT-FOOD SCIENCE AND TECHNOLOGY
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2021
·
IF 4.952
Shihuan Li,Jinhui Li,Senwei Feng,Linlin Bian,Zhuoting Liu,Yunfang Ping,Xu Wang,Ann Van Schepdael
The presence of fatty acid esters of 3-monochloropropane-1,2-diol (3-MCPDE), 2-monochloropropane-1,3-diol (2-MCPDE) and glycidyl (GE) in foods is a potential concern due to their toxicity, especially for infants. This study proposed a rapid, sensitive and environmentally friendly method for simultaneous determination of the 3-/2-MCPDE and GE in breast milk and infant formula using headspace solid-phase microextraction (SPME) and on-fiber derivatization combined with gas chromatography-tandem mass spectrometry (GC-MS/MS). The approach proved high sensitivity with detection limits of 0.10 μg/L and 0.15 μg/kg for MCPDEs in breast milk and infant formula, respectively. Mean recoveries were obtained ranging from 79.9 to 111.2% for breast milk and from 82.1 to 106.7% for infant formula, with relative standard deviation (RSD) of less than 9.5%. According to the levels of 3-MCPDE and GE determined in 30 breast milk and 23 infant formulas, the exposure to 3-MCPDE and GE may pose a potential health risk for infants from birth to <12 months fed by breast milk and infants from birth to 6 months fed by infant formula.
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高影响因子
JOURNAL OF SEPARATION SCIENCE
·
2017
·Vol. 40
·期 12
·2528-2540
·
IF 2.557
Jinmao You,Kun Dou,Cuihua Song,Guoliang Li,Zhiwei Sun,Shijuan Zhang,Guang Chen,Xianen Zhao,Na Hu,Wu Zhou
A rapid, sensitive, and selective precolumn derivatization method for the simultaneous determination of eight thiophenols using 3-(2-bromoacetamido)- N -(9-ethyl-9 H )-carbazol as a labeling reagent by high-performance liquid chromatography with fluorescence detection has been developed. The labeling reagent reacted with thiophenols at 50°C for 50 min in aqueous acetonitrile in the presence of borate buffer (0.10 mol/L, pH 11.2) to give high yields of thiophenol derivatives. The derivatives were identified by online postcolumn mass spectrometry. The collision-induced dissociation spectra for thiophenol derivatives gave the corresponding specific fragment ions at m/z 251.3, 223.3, 210.9, 195.8, and 181.9. At the same time, derivatives exhibited intense fluorescence with an excitation maximum at λ ex = 276 nm and an emission maximum at λ em = 385 nm. Excellent linear responses were observed for all analytes over the range of 0.033–6.66 μmol/L with correlation coefficients of more than 0.9997. Detection limits were in the range of 0.94–5.77 μg/L with relative standard deviations of less than 4.54%. The feasibility of derivatization allowed the development of a rapid and highly sensitive method for the quantitative analysis of trace levels of thiophenols from some rubber products. The average recoveries ( n = 3) were in the range of 87.21–101.12%.
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PubMed
高影响因子
ACS Omega
·
2024
·
IF 3.7
Tengjiao Fan,Lin Shen,Yaxin Huang,Xin Wang,Lijiao Zhao,Rugang Zhong,Peng Wang,Guohui Sun
Lung cancer ranks as the second most diagnosed cancer and the leading cause of cancer-related deaths worldwide. Novel chemotherapeutic strategies are crucial to efficiently target tumor cells while minimizing toxicity to normal cells. In this study, we proposed a combination strategy using energy blocker lonidamine (LND) and cytotoxic drug nimustine (ACNU, 1-[(4-amino-2-methyl-5-pyrimidinyl)methyl]-3-(2-chloroethyl)-3-nitrosourea) to enhance the killing of a human lung cancer cell line and investigated the potential chemo-sensitizing mechanism of LND. LND was found to remarkably increase the cytotoxicity of ACNU to A549 and H1299 cells without significantly affecting normal lung BEAS2B cells. The combination of LND and ACNU also produced significant effects on cell apoptosis, colony formation, cell migration, and invasion assays compared to single drug treatment. Mechanistically, LND decreased intracellular ATP levels by inhibiting glycolysis and inducing mitochondrial dysfunction. Furthermore, the combination of LND and ACNU could intensify cellular oxidative stress, decrease cellular GSH contents, and increase reactive oxygen species (ROS) production. Notably, LND alone dramatically downregulated the expression of DNA repair protein MGMT (O6-methylguanine-DNA methyltransferase), enhancing DNA interstrand cross-link formation induced by ACNU. Overall, LND represents a potential chemo-sensitizer to enhance ACNU therapy through energy inhibition, disrupting redox homeostasis and downregulating MGMT expression in human lung cancer cell line under preclinical and clinical background.
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PubMed
高影响因子
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