o-Quinonemethide was efficiently produced by photoirradiation of phenolic Mannich bases in aqueous acetonitrile with low energy UV light. The photoreaction proceeds most effectively at neutral pH in aqueous solvents.
Synthesis and characterization of a novel poly(arylene ether sulfone) containing pendent imidazole groups for high temperature proton exchange membranes
作者:Jing Wang、Jifu Zheng、Zhuo Zhao、Suobo Zhang
DOI:10.1039/c2jm34417c
日期:——
A series of poly(arylene ether sulfone) containing pendent imidazole groups (PSf-Im-x) have been successfully synthesized based on a novel monomer 2,2′-bis-(2-methyl-imidazol-1-yl-methyl)-biphenyl-4,4′-diol (MIPO). The pendent imidazole groups along the polymer chain were expected to provide functional sites for the acid–base interaction with the doping phosphoric acid (PA) when they are used as polymer electrolyte membranes for high temperature fuel cell applications. The PA content of the linear PSf-Im-x membranes is about 172.3–235.8% in 85 wt% H3PO4 at room temperature. The volume swelling of these membranes is 114.4–194.0%, lower than that of polybenzimidazole (PBI) with similar PA content. The proton conductivities of the membranes are 0.021–0.053 S cm−1 at 140 °C under absolutely dehydrated state. The low volume swelling and good proton conductivity may be attributed to the “side-chain-type” structures of pendent imidazole groups, which facilitate ion transport. To obtain higher acid doping while maintaining mechanical properties, cross-linked membranes were prepared by the reaction of the imidazole group of the polymer and p-xylene dichloride. The PA content of the membranes with 20% cross-linking is 313.2% in 85 wt% H3PO4 at 80 °C. The stress at breaking and the proton conductivity of the membrane is 3.2 MPa at room temperature and 0.063 S cm−1 at 140 °C in an absolutely dehydrated state.
基于新型单体2,2'-双-(2-甲基-咪唑-1-基-甲基)-,成功合成了一系列含有咪唑侧基的聚亚芳基醚砜(PSf-Im-x)。联苯-4,4′-二醇(MIPO)。当它们用作高温燃料电池应用的聚合物电解质膜时,沿着聚合物链的悬挂咪唑基团有望为与掺杂磷酸(PA)的酸碱相互作用提供功能位点。室温下,在 85 wt% H3PO4 中,线性 PSf-Im-x 膜的 PA 含量约为 172.3-235.8%。这些膜的体积膨胀率为114.4-194.0%,低于具有相似PA含量的聚苯并咪唑(PBI)。在140 ℃、绝对脱水状态下,膜的质子电导率为0.021-0.053 S cm−1。低体积膨胀和良好的质子传导性可能归因于悬挂咪唑基团的“侧链型”结构,这有利于离子传输。为了在保持机械性能的同时获得更高的酸掺杂,通过聚合物的咪唑基团与对二甲苯二氯的反应制备了交联膜。 80°C、85 wt% H3PO4 中,20% 交联的膜的 PA 含量为 313.2%。在绝对脱水状态下,膜的断裂应力和质子电导率在室温下为3.2 MPa,在140 ℃下为0.063 S cm−1。
Mathai,K.P., Journal of the Indian Chemical Society, 1966, vol. 43, # 6, p. 421 - 424
作者:Mathai,K.P.
DOI:——
日期:——
A Potent, Water-Soluble and Photoinducible DNA Cross-Linking Agent
Water-soluble DNA cross-linking phenol and biphenol derivatives 3 and 6 have been synthesized by a Mannich reaction. Both of them can cross-link DNA by photoactivation using visible light (wavelength > 400 nm). Compound 6 can cross-link DNA at pH 5.0 and 7.7, whereas no cross-link was observed at pH 10.0. Density functional theory (DFT) calculation indicated that 6 displays a twist structure. Therefore, it could bind to DNA naturally and has potent property to cross-link DNA after photoactivation.
A thiol-inducible and quick-response DNA cross-linking agent
作者:Yuanzhen Xu、Hongbo Wei、Jianjun Chen、Kun Gao
DOI:10.1016/j.bmcl.2018.11.040
日期:2019.1
release the corresponding phenol derivatives (4–6) within 5 min. The quick response of 1–3 toward thiols was determined by 1H NMR and HPLC. Moreover, our results indicated that 1 could induce DNAcross-linking in the presence of glutathione, probably due to the quinone methide formation of phenol intermediate 4 followed by departure of 2,4-dinitrobenzenesulfonyl group.
三个新的2,4-二硝基苯衍生物1 - 3使用一个简单的过程中的第一次成功制备。它们被硫醇(谷胱甘肽和1-半胱氨酸)有效触发,在5分钟内释放出相应的苯酚衍生物(4 – 6)。的快速反应1 - 3朝向硫醇通过测定1 H NMR和HPLC。此外,我们的结果表明1可以在存在谷胱甘肽的情况下诱导DNA交联,这可能是由于苯酚中间体4的醌甲基化物形成,接着是2,4-二硝基苯磺酰基的离开。