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131.
132.
综述了Merrifield树脂在固相有机合成中的应用研究进展, 主要包括两个方面: (1)在合成Merrifield树脂上的不同连接体中的应用; (2)Merrifield树脂在有机合成反应中的应用. 相似文献
133.
A general method is reported for the parallel solid-phase synthesis of hydroxypiperazine derivatives based on the oxidation-Cope elimination of polymer-bound phenethylamine linker with m-CPBA. The key intermediate of phenethylamine N-oxide resins was separable on solid-phase for subsequent β-elimination, from which the desired hydroxypiperazine products could be obtained in high purities and yields without any significant contamination at 90 °C for 2 h. The utility of the methodology for solid-phase synthesis of general hydroxylamines was also investigated using the same linker. The progress of reactions could be monitored on polymer bound intermediates by ATR-FTIR spectroscopy on single bead. The desired products were obtained in good six-step overall yields upon cleavage from the resins and were characterized by LC/MS, 1H NMR, and 13C NMR spectroscopy. 相似文献
134.
135.
Yi-Fan Chang 《Tetrahedron letters》2008,49(3):543-547
The highly efficient and convenient protocol to prepare diverse α,β-unsaturated aldehydes, ketones, and acids via the parallel solid-phase synthesis is developed. The key sulfone linker cleavage strategy is performed by ozonolysis to generate a carbonyl moiety followed by base-mediated polymer-bound sulfinate elimination to release our desired molecules from the resin. All α,β-unsaturated carbonyl compounds are prepared in good purities and yields without further purification. 相似文献
136.
Ya-Ping Ou Jing Zhang Daizhi Kuang Fuxing Zhang Jiangxi Yu Xiaoming Zhu 《Journal of Coordination Chemistry》2017,70(4):722-733
A mononuclear iron complex with 2-ethynylbenzo[b]thiophene C-coordinated to the (η5-Cp*)(η2-dppe)Fe (Cp* = pentamethylcyclopentadienyl, dppe = 1,2-diphenylphosphinoethane) framework (1) was prepared and characterized by 1H NMR, elemental analysis, and single crystal X-ray diffraction. The redox behavior of 1 was investigated by voltammetric methods and anodic spectroelectrochemistry in the UV–vis-NIR-IR region and compared with reference complexes including 2-ferrocenylbenzo[b]thiophene (2) and the 2-ethynylpyridine derivative of 1. The spin density distribution along the linear molecular backbone in 1+ was analyzed by DFT (BLYP35) and TDDFT calculations of a truncated model complex. The combined experimental and theoretical results revealed an important role of the ethynylene linker in determining the redox properties of this family of complexes and participation of the 2-ethynylbenzo[b]thiophene framework in the largely iron-based anodic electron transfer. 相似文献
137.
Single‐Crystal to Single‐Crystal Linker Substitution,Linker Place Exchange,and Transmetalation Reactions in Interpenetrated Pillared–Bilayer Zinc(II) Metal–Organic Frameworks 下载免费PDF全文
Dinesh De Dr. Subhadip Neogi Prof. E. Carolina Sañudo Prof. Parimal K. Bharadwaj 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(48):17422-17429
A twofold interpenetrated pillared–bilayer framework, {[Zn3( L )2( L2 )(DMF)] ? (18DMF)(6H2O)}n ( 1 ), has been synthesized from the ligands tris(4′‐carboxybiphenyl)amine ( H3L ) and 1,2‐bis(4‐pyridyl)ethylene ( L2 ). The structure contains [Zn3(COO)6] secondary building units (SBUs), in which three ZnII ions are almost linear with carboxylate bridging. This framework undergoes reversible pillar linker substitution reactions at the terminal ZnII centers with three different dipyridyl linkers of different lengths to afford three daughter frameworks, 2 – 4 . Frameworks 2 – 4 are interconvertible through reversible linker substitution reactions. Also, competitive linker‐exchange experiments show preferential incorporation of linker L3 in the parent framework 1 . The larger linker L5 does not undergo such substitution reactions and framework 5 , which contains this linker, can be synthesized solvothermally as a twofold interpenetrated structure. Interestingly, when framework 5 is dipped in a solution of L3 in DMF, linker substitution takes place as before, but linker L5 now moves and diagonally binds two ZnII centers to afford 6 as a nonpenetrated single framework. This linker place exchange reaction is unprecedented. All of these reactions take place in a single‐crystal to single‐crystal (SC‐SC) manner, and have been observed directly through X‐ray crystallography. In addition, each 3D framework undergoes complete copper(II) transmetalation. 相似文献
138.
A Simple NMR‐Based Method for Studying the Spatial Distribution of Linkers within Mixed‐Linker Metal–Organic Frameworks 下载免费PDF全文
Andraž Krajnc Dr. Tomaž Kos Prof. Nataša Zabukovec Logar Prof. Gregor Mali 《Angewandte Chemie (International ed. in English)》2015,54(36):10535-10538
The spatial distribution of different linkers within mixed‐linker metal–organic frameworks crucially influences the properties of such materials. A simple and robust approach based on 1H spin‐diffusion magic‐angle‐spinning nuclear magnetic resonance measurements and modeling of spin‐diffusion curves is presented; this approach facilitates the distinction between homogeneous and clustered distributions. The performance of the approach is demonstrated with an example of an aluminum‐based metal–organic material DUT‐5, which has framework consisting of biphenyl and bipyridyl dicarboxylic linkers. The distribution is shown to be homogeneous in this material. The approach could be applied to studying other spatially disordered crystalline materials. 相似文献
139.
以四溴乙烷、吡唑及4-碘吡唑为原料在KOH-DMSO体系中合成了3种双二(吡唑)烷四齿桥联配体: 1,1,2,2-四(吡唑)乙烷(1)、1,1,2,2-四(4-硝基吡唑)乙烷(2)和1,1,2,2-四(4-碘吡唑)乙烷(3), 通过元素分析、红外光谱、1H NMR、13C NMR谱表征了它们的结构. 用X-射线单晶衍射法测试了化合物2以及不同分子构型的3-1和3-2的晶体结构. 用Gaussian09量子化学程序包, 采用密度泛函理论(DFT)中的B3LYP方法, 对化合物2, 3-1, 3-2的分子结构进行全参数优化计算, 研究了3个化合物的稳定性、电荷分布. 将量子化学计算结果与单晶衍射实验结果进行了对比分析, 发现二者具有相当高的一致性. 相似文献
140.
分别以CuI 和InAc3 作为铜源和铟源, 十二硫醇(DDT)作为硫源, 采用直接加热法合成不同尺寸的CuInS2 (CIS)量子点. 运用X射线衍射(XRD), 拉曼光谱(Raman), 高分辨率透射电镜(HRTEM), 紫外-可见(UVVis)吸收光谱表征其相结构、形貌及光学性能. 结果表明: 制备的CIS量子点为黄铜矿结构, 且随着时间的延长, 量子点逐渐长大, 吸收光谱的激子吸收峰逐渐红移, 表现出量子尺寸效应. 采用巯基乙酸为双功能耦联剂辅助吸附法制备CIS敏化的TiO2薄膜. 通过衰减全反射红外光谱(ATR-FTIR)分析得出, 巯基乙酸上的羧基与TiO2表面羟基连接, 另一端上的巯基代替长链的DDT与CIS 耦联, 将CIS 成功锚定在TiO2表面. 该方法不仅操作简单, 而且容易实现CIS在TiO2表面的吸附. 太阳电池光电性能测试表明, 粒径大小约为3.6 nm的CIS量子点表现出最优的吸附能力以及光电转换性能. 进一步采用连续离子吸附层法对CIS敏化的TiO2薄膜进行CdS包覆, 光电转换性能大大提高, 其效率达到2.83%, 这主要源于CdS的包覆钝化了CIS 的表面缺陷, 有效地降低了电子复合. 相似文献