由于CO 2 固有的热力学稳定性和动力学惰性,将CO 2非均相催化转化为环状碳酸酯通常需要苛刻的操作条件、高温高压和助催化剂的添加。因此,在无助催化剂和温和条件下开发高效的多相催化剂用于 CO 2转化一直是一个挑战。在此,合成了一种罕见的四配位Cd-MOF并用于催化CO 2在不添加任何助催化剂的情况下高效地进行环加成反应,并通过一系列实验系统地研究了其催化机理,包括荧光分析、X射线光电子能谱、微量热法和密度泛函理论(DFT)计算。Cd-MOF具有 3D 超分子结构,具有 1D 11.6 × 7.7 Å 2通道,丰富的路易斯酸/碱和 I -位点位于受限通道中,提高了 CO 2的效率在 60 °C 和 0.5 MPa 条件下,转化率最高为 98.2%,周转数值为 1080.11,远远超过大多数原始 MOF 基催化系统。结合实验和 DFT 计算表明,暴露的 Cd(II) Lewis 酸位点迅速参
Synthesis and characterization of trinuclear N-heterocyclic carbene–palladium(<scp>ii</scp>) complexes and their applications in the Suzuki–Miyaura cross-coupling reaction
Five novel trinuclear N-heterocyclic carbene–palladium(II) complexes 5a–e were conveniently synthesized through one-pot reactions of imidazolium salts, tridentate N-heterocycles tris(4-(pyridin-4-yl)phenyl)amine or tris(4-(pyridin-3-yl)phenyl)amine} and palladium chloride in one step. All of the new complexes have been fully characterized by elemental analysis, 1H, 13C NMR, and IR spectra. Among them
五个新颖三核N-杂环卡宾-钯(II)配合物5A-E是方便地通过咪唑鎓盐,三齿N-杂环三(4-(吡啶-4-基)苯基)胺或三的一锅反应合成(一步合成4-(吡啶-3-基)苯基)胺}和氯化钯。所有这些新的配合物均已通过元素分析,1 H,13 C NMR和IR光谱进行了全面表征。其中,配合物5d的分子结构已经通过X射线单晶衍射确定。另外,得到的三核钯(II)络合物是芳烃以及苄基氯与芳基硼酸的Suzuki-Miyaura偶联的有效催化剂前体。在最佳反应条件下,以良好至几乎定量的产率获得了预期的联芳基产物。
Pillar–template strategy switching the redox activity and magnetic properties of trisphenylamine-based coordination polymers
作者:Ya-Ru Qiu、Bang Li、Yan Zhou、Jian Su、Jing-Yuan Ge
DOI:10.1039/d0ce00256a
日期:——
two-dimensional (2D) layered CPs. Compound 4, [Co(m-NPy3)(TPA)0.5Cl·CH3OH]n (TPA = bidentate terephthalic acid), is a three-dimensional (3D) CP, which is pillared by linear bidentate terephthalic acid (TPA) linkers. Notably, with the presence of TPA, the layered compound 1 can be further assembled to the 3D pillared-layer architecture 4 by single-crystal-to-single-crystal (SC–SC) transformation. All the compounds
Dynamic Metal–Iodide Bonds in a Tetracoordinated Cadmium-Based Metal–Organic Framework Boosting Efficient CO<sub>2</sub> Cycloaddition under Solvent- and Cocatalyst-Free Conditions
resulting large steric hindrance facilitates leaving of the coordinated iodide ions in a reversibly dynamic fashion convenient for the rate-determining step ring-opening as a strong nucleophile. Such a pristine MOF catalyst with self-independent catalytic ring-opening overcomes the complicated operation limitation of the traditional cocatalyst-free MOF systems based on encapsulating/postmodifying cocatalysts
由于CO 2 固有的热力学稳定性和动力学惰性,将CO 2非均相催化转化为环状碳酸酯通常需要苛刻的操作条件、高温高压和助催化剂的添加。因此,在无助催化剂和温和条件下开发高效的多相催化剂用于 CO 2转化一直是一个挑战。在此,合成了一种罕见的四配位Cd-MOF并用于催化CO 2在不添加任何助催化剂的情况下高效地进行环加成反应,并通过一系列实验系统地研究了其催化机理,包括荧光分析、X射线光电子能谱、微量热法和密度泛函理论(DFT)计算。Cd-MOF具有 3D 超分子结构,具有 1D 11.6 × 7.7 Å 2通道,丰富的路易斯酸/碱和 I -位点位于受限通道中,提高了 CO 2的效率在 60 °C 和 0.5 MPa 条件下,转化率最高为 98.2%,周转数值为 1080.11,远远超过大多数原始 MOF 基催化系统。结合实验和 DFT 计算表明,暴露的 Cd(II) Lewis 酸位点迅速参
Anion-induced differential assembly and structural transformation of supramolecular coordination cages
The intimate host-anion interactions will regulate thermodynamics and kinetics in the self-assembly of cationic cages mimicking biological counterparts. Herein, we report construction and transformation of three Pd(II)-based metal-organic cages (MOCs) depending on different anions. Stoichiometric conversions of the lantern-shaped MOC-34 into either octahedral MOC-35 or tricapped trigonal prism MOC-36