A Mild and Efficient Deprotection of Geminal Diacetates Catalyzed by FeCl3 ·6H2O in Ionic Liquid

The selective deprotection of geminal diacetates promoted by FeCl3·6H2O in the ionic liquid [bmim] [BF4] canbe efficiently achieved in good yields. The ionic liquid and the catalyst can be recycled easily and the process is car ried out under mild conditions.     

β-环糊精对菁染料光稳定性的影响

超分子化学;β-环糊精对菁染料光稳定性的影响     

苯胺与氨基甲酸甲酯合成苯氨基甲酸甲酯反应研究

以无水氯化锌为催化剂,考察了温度、时间、催化剂含量及原料配比等条件对合成反应的影响,确定了最优化反应条件,并初步探讨了反应机理.最佳反应条件下MPC收率可达89.90%,选择性为99.76%.     

硝酸氯冰溶胶水解反应过程的计算模拟

用二级微扰(MP2)和密度泛函理论(B3LYP),辅以不同的基组,对硝酸氯在冰表面上水解反应的机理进行了理论计算研究.根据关键部位化学键的松弛效应和关键原子的电荷分布,对冰表面催化的原因进行了深入分析.水分子一方面作为桥,辅助分子间质子发生迁移;另一方面作为连续介质,通过偶极相互作用加快硝酸氯的水解过程.     

染料分子对硫纳米微粒共振散射光谱的影响

在聚丙烯酰胺存在下液相硫纳米微粒在 470nm处产生 1个强共振散射峰 ;在可见光范围内无吸收峰且吸收值较小。硫微粒质量浓度在 0 0 5～ 1 0mg/L范围内与I4 70nm间有良好线性关系。研究了乙醇、丙酮 ,以及溴酚蓝、溴甲基紫、结晶紫、亮绿等有机染料对硫纳米微粒共振散射的影响。结果发现 ,染料分子吸收是产生共振散射峰的一个重要原因 ;随着染料分子非辐射吸收值的增大 ,硫纳米微粒共振散射光强度降低。实验证明 ,溴酚蓝浓度在 0～ 1 0× 10 -5mol/L范围内 ,在溴酚蓝最大吸收波长 5 90nm处的ΔI590nm与溴酚蓝浓度呈线性关系。     

专业课"课程思政"策略的构建与实践——以基础化学原理课程为例

目前高等教育仅依靠思想政治理论课对大学生进行价值引领的局限性日趋凸显,亟需构建和实施全员育人的大思政教育体系——"课程思政"。尝试构建了专业课"课程思政"的策略。通过"培养学生的爱国主义精神、民族自豪感和自信心、对学生进行生态文明和生态安全教育、培养学生的专业品质、培养学生的专业能力"等途径,进行了基础化学原理"课程思政"实践,充分发挥了基础化学原理课程的"育德功能"。     

危险化学品家族

The dangerous chemicals are special chemicals. They are very important to human being though they are dangerous generally. In this paper, we will vividly introduce the family of dangerous chemicals and classification so that readers can better understand them.     

注重基础促进交叉尊重选择培育英才 ——北京大学化学学科"拔尖计划"十年

北京大学化学与分子工程学院在实施基础学科拔尖学生培养计划过程中,实行动态管理制度,低年级统一培养,高年级通过制定个性化教学方案和参加科研训练的办法遴选拔尖学生,探索"扎根课堂打好基础,依托科研提高能力,着眼交流开阔眼界"的培养模式,实现"以高水平科研带动创新人才培养"的目标。在基础核心课程中设置平行的英文班和阅读讨论班以适应不同学生的需求。2016年,随着北京大学综合改革计划的推进,进一步明确了"一体化、多层次、开放式、重基础、求创新"的教学指导思想,在注重化学基础理论知识和基本实验方法培养、注重数学和物理基础知识学习的基础上,构建多样化和多模式的立体课程体系,为学生提供适合的课程学习和个性化学术发展途径。     

碳纳米管薄膜的制备及其在柔性电子器件中的应用

近年来,柔性电子器件的发展日新月异。以碳纳米管为代表的碳纳米材料,尤其是其组装成的宏观结构碳纳米管薄膜具有良好的柔性和优异的导电性,且具有化学稳定、热稳定、光学透明性等优点,在柔性电子领域展现了极大的应用潜力。本文简要综述了近年来碳纳米管薄膜在柔性电子器件领域的研究进展。首先详细介绍了碳纳米管薄膜的两类主要制备方法,分别为干法制备和湿法制备;继而介绍了碳纳米管薄膜在多种柔性电子器件的组装、性能与应用方面的最新研究进展;最后总结了碳纳米管薄膜基柔性电子领域的发展现状,并讨论了该领域所面临的挑战及其未来前景。     

1, 1'-双(二苯基膦基)二茂铁介导的芳烃碳氢键芳基化反应制备联芳基骨架

The broad existence of the biaryl linkage in bioactive organic molecules and functional materials makes it an attractive synthesis target via construction of aryl-aryl carbon bonds. Transition metal catalyzed cross-coupling reactions of two pre-functionalized aryl partners, e.g., Suzuki-Miyaura cross-coupling and Negishi cross-coupling reactions, are the main methods typically used for the construction of biaryl linkages. Since the end of the last century, transition metal catalyzed direct C―H arylation of unactivated arenes has emerged as a practical alternative to the well-established cross-coupling strategies. However, the use of transition metal catalysts and/or organometallic reagents would lead to problems, such as the disposal of waste from large-scale syntheses and the removal of heavy metal contaminants from pharmaceutical intermediates. In this regard, the base-promoted homolytic aromatic substitution (BHAS) reaction of aryl halides with unactivated arenes offers a simpler strategy for the synthesis of biaryl scaffolds, and avoids the use of transition metals. Although the BHAS reaction can proceed to a small extent without any additives, particularly at elevated temperatures, the addition of organic promoters would significantly accelerate the reaction rate and improve the overall efficiency of the process. Over the past ten years, a wide variety of N- and O-based organic promoters have been developed to promote the BHAS reaction in the presence of the tert-butoxide base. The mechanism of the BHAS reaction has been studied extensively, and is accepted as occurring via a radical chain process involving an aryl radical. However, the role and mode of initiation of most organic promoters studied remain controversial. The development of more and varied organic promoters will surely promote the mechanistic understanding and further development of the BHAS reaction. Herein, we report that 1, 1'-bis(diphenylphosphino)ferrocene (dppf, or DPPF) can act as a P-based promoter to facilitate the direct arylation of unactivated arenes with aryl iodides using potassium tert-butoxide as the base and electron donor. A broad range of aryl iodides and arenes reacted smoothly under the optimized reaction conditions, giving arylated products in good yields and with high regio-selectivity. Intramolecular C―H arylation also worked well following a sequence of single electron transfer (SET)/initiation, 5-exo-trig aryl radical addition, ring expansion, deprotonation, and re-aromatization/propagation. A mechanistic study indicated that the diphenylphosphino group of dppf played a vital role in the initiation step by enhancing the SET-inhibiting ability of the tert-butoxide anion. A primary kinetic isotope effect was observed in the parallel reactions between 4-methoxy-iodobenzene with benzene and deuterated benzene, implying that the deprotonation of the cyclohexadienyl radical intermediate by tert-butoxide was the rate-determining step in the radical chain pathway.