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排序方式: 共有571条查询结果,搜索用时 140 毫秒
21.
Natsuki Yamashita Atsuhito Tadokoro Eiichiozu Toshihisa Maeshima Ion C. Baianu Lun-Shin Wei 《高分子科学杂志,A辑:纯化学与应用化学》2013,50(10):1223-1239
The anionic polymerization of acrolein (AL) with N, N-dimethylamino-propylacrylamide (DMAPA) in the presence of water was investigated in tetrahydrofuran, benzene, and ethanol at 0°C in a nitrogen atmosphere. The resulting polymers were found to be essentially vinyl polymers with one DMAPA attached and an aldehyde side chain. From observations of the polymerization process by 1H NMR, we find that polymerization was initiated by the hydroxyl anion formed in the thermodynamic equilibrium between the amine of DMAPA and water. The hydrogen transfer reaction of DMAPA was caused by the propagating poly-AL anion. On the other hand, the monomer reactivity ratios and the Q2-e2values of DMAPA were determined by the free-radical copolymerization of styrene (St, M1) with DMAPA and AIBN as initiator. 相似文献
22.
1-(Primary alkyl)benzotriazoles are obtained in convenient yields by treating the corresponding alcohol with triphenylphosphine, N-bromosuccinimide and benzotriazole. Under these conditions, the alcohols gave exclusively the corresponding 1-alkyl-benzotriazoles. Allyl and propargyl alcohols also reacted regiospecifically in a typical Sn2 manner, and no products derived from prototropic rearrangement were found. 相似文献
23.
The paper deals with the study of the thermotropic liquid crystalline properties of a new azomethinic symmetric dimer and some of its structural heterogeneous mixtures with one of its reagents. Their thermotropic behaviour was monitored by polarised light microscopy, differential scanning microscopy and variable temperature X-ray diffraction measurements. The influence of the structural heterogeneity on the mesomorphic behaviour was established and some similarities with the mesomorphic behaviour of the polydisperse polymers were underlined. 相似文献
24.
Ariana Hudita Bianca Galateanu Marieta Costache Carolina Negrei Rodica-Mariana Ion Lorena Iancu Octav Ginghina 《Molecules (Basel, Switzerland)》2021,26(5)
Chronic neuropathic pain, particularly peripheral pain, is a cause of great concern for diabetic patients. Current treatments include numerous agents such as capsaicinoids, a known deterrent of neuropathic pain despite the inconvenience associated with local side effects. In this context, the current work aims to elucidate the potential mechanisms involved in cytotoxicity by capsaicin and proposes an efficient formulation of capsaicin in alginate microcapsules, which significantly reduces side effects from capsaicin topical administration. For this, human dermal fibroblast cells were treated with alginate-microencapsulated capsaicin extracts and screened for potential cytotoxic effects produced by the treatment. Cell viability and morphology were examined, as well as oxidative stress status and anti-inflammatory potential. Our results show that the alginate encapsulated formulation of capsaicin exerted lower cytotoxic effects on human dermal fibroblasts as measured by cell viability and reactive oxygen species (ROS) production. Furthermore, the expression profiles of inflammatory cytokines were significantly altered by the treatment as compared with the control culture. 相似文献
25.
26.
Mihaela Badea Larisa Calu Mariana Carmen Chifiriuc Coralia Bleotu Alexandra Marin Sebastian Ion Gabriela Ioniţă Nicolae Stanică Luminiţa Măruţescu Veronica Lazăr Dana Marinescu Rodica Olar 《Journal of Thermal Analysis and Calorimetry》2014,118(2):1145-1157
A series of complexes of type [ML(CH3COO)(OH2)2] (M: Co, Ni; HL: 2-[(E)-1H-1,2,4-triazol-3-ylimino)methyl]phenol)) and [M2L2(CH3COO)2(OH2)n] (M: Cu, n = 2; M: Zn, n = 0) were synthesised by template condensation. The compounds were characterised with microanalytical, ESI–MS, IR, electronic, EPR spectra and magnetic data at room temperature. Based on the IR and ESI–MS spectra, a dinuclear structure with the acetate as bridge was proposed for Cu(II) and Zn(II) complexes. The dinuclear structure of Cu(II) complex is also consistent with both magnetic behaviour and EPR spectrum. The thermal analyses have evidenced processes as water elimination, acetate decomposition, as well as oxidative degradation of the Schiff base. The final decomposition product was the most stable metal oxide as indicated by powder X-ray diffraction. The cobalt and copper compounds exhibited a broad spectrum of antibacterial activity towards both planktonic and biofilm-embedded cells. The complexes exhibit a low cytotoxicity except for Cu(II) species that induces the early apoptosis for the HEp 2 cells. 相似文献
27.
A series of new poly(1,3,4-oxadiazole-amide)s containing pendent imide groups has been synthesized by solution polycondensation of aromatic diamines containing preformed 1,3,4-oxadiazole rings with two diacid chlorides containing imide rings. These polymers were also prepared by the reaction of the same diacid chlorides with p-aminobenzhydrazide which were subsequently cyclodehydrated in solid state. The polymers were soluble in polar amidic solvents and some of them gave transparent flexible films by casting from solutions. They showed high thermal stability with decomposition temperatures above 400°C and glass transition temperatures in the range of 245–327°C. They had low dielectric constants, in the range of 3.32–3.94, and good tensile properties. 相似文献
28.
Alan R. Katritzky Dai Cheng Peter Leeming Ion Ghiviriga Chris M. Hartshorn Peter J. Steel 《Journal of heterocyclic chemistry》1996,33(6):1935-1941
N,N-Dimethylaminobenzotriazolylcarbene ( 5 ) reacted with phenyl isocyanate in a [1+2+2] cycloaddition and then with nucleophiles to generate various hydantoins 10 in a one-pot procedure. It was also found that this novel carbene reacted with trans-dibenzoylethylene ( 11 ) in a [1+4] cycloaddition, generating 2-dimethylamino-3-benzoyl-5-phenylfuran ( 13 ) and 2-phenyl-3-[benzotriazol-1-yl]-4-benzoylfuran ( 14 ) whose structures were confirmed by 1H-13C long range correlations as well as the structure of furan 14 being confirmed by X-ray crystallography. 相似文献
29.
Cecilia-Sperana Georgescu Victor Butucea Adrians Sarbu Adrians Ionescu Ion Deaconescu Cornel Hagiopol 《Macromolecular Symposia》1989,29(1):329-337
Decomposition of potassium persulfate in sodium dodecyl sulfate solutions (of concentrations under and above CMC) and in the presence of poly(vinyl chloride) and vinyl chloride was studied. The decomposition rate has a maximum close to the CMC value of the final solutions. On the basis of experimental data a hemolytic mechanism in which a radical derived from dodecyl sulfate participates is proposed. 相似文献
30.
Natalia Terenti Gavril-Ionel Giurgi Lorant Szolga Ioan Stroia Anamaria Terec Ion Grosu Andreea Petronela Crian 《Molecules (Basel, Switzerland)》2022,27(4)
Four acceptor–donor–acceptor (A–D–A)-type molecules bearing indacenodithiophene as donating central core and various end-capping acceptor units have been designed and synthesised as n-type materials suitable for organic solar cells (OSCs). The studied optical and electrochemical properties supported by theoretical calculations revealed that the nature and the strength of the terminal groups exert a decisive influence on the polymer bulk-heterojunction OSC performance. 相似文献