Gating the photochromism of an azobenzene by strong host–guest interactions in a divalent pseudo[2]rotaxane
作者:Mirko Lohse、Karol Nowosinski、Nora L. Traulsen、Andreas J. Achazi、Larissa K. S. von Krbek、Beate Paulus、Christoph A. Schalley、Stefan Hecht
DOI:10.1039/c5cc02811f
日期:——
Photoisomerisation of an E-configured azobenzene guest is controlled by a complementary host leading to formation of a divalent pseudo[2]rotaxane complex.
一种E构型的偶氮苯客体的光异构化受到互补宿主的控制,导致形成二价伪[2]轮轴状复合物。
Naphthyridine tetramer with a pre-organized structure for 1:1 binding to a CGG/CGG sequence
A naphthyridine carbamate dimer (NCD) is a synthetic ligand for DNA containing a CGG/CGG sequence. Although NCD can bind selectively and tightly to a CGG/CGG sequence, the highly cooperative 2:1 binding mode has hampered precise analysis of the binding. We describe herein the synthesis of a series of naphthyridine tetramers consisting of two NCD molecules connected with various linkers to seek a ligand that binds to a CGG/CGG sequence exclusively with a 1:1 stoichiometry. Among the tested ligands, NCTB and Z -NCTS, which have linker moieties with restricted conformational flexibility [biphenyl and (Z) -stilbene linker, respectively], gave the exclusive formation of a 1:1 ligand–CGG/CGG complex. The (Z) -stilbene linker in Z -NCTS was designed to have pre-organized conformation appropriate for the binding and, in fact, resulted in the highest binding affinity. Thermodynamic parameters obtained by isothermal titration calorimetry indicated that the stronger binding of Z -NCTS was attributed to its lower entropic cost. The present study provides not only a novel 1:1 binding ligand, but also valuable feedback for subsequent molecular design of DNA and RNA binding ligands.
萘啶氨基甲酸酯二聚体(NCD)是含有 CGG/CGG 序列的 DNA 的合成配体。虽然 NCD 可以选择性地与 CGG/CGG 序列紧密结合,但其高度合作的 2:1 结合模式阻碍了对这种结合的精确分析。我们在本文中描述了一系列萘啶四聚体的合成过程,这些四聚体由两个 NCD 分子与各种连接体连接而成,目的是寻找一种配体,以 1:1 的化学计量学比例完全与 CGG/CGG 序列结合。在测试的配体中,NCTB 和 Z -NCTS 具有构象灵活性受限的连接分子[分别为联苯和 (Z) - 二苯乙烯连接分子],这两种配体都能形成 1:1 的配体-CGG/CGG 复合物。在 Z -NCTS 中,(Z) - 二苯乙烯连接体被设计成具有适合结合的预组织构象,事实上,这种连接体具有最高的结合亲和力。通过等温滴定量热法获得的热力学参数表明,Z -NCTS 的较强结合力归因于其较低的熵成本。本研究不仅提供了一种新型的 1:1 结合配体,还为后续 DNA 和 RNA 结合配体的分子设计提供了宝贵的反馈信息。
One-Step Synthesis of [16]Helicene
作者:Kazuyuki Mori、Takashi Murase、Makoto Fujita
DOI:10.1002/anie.201502436
日期:2015.6.1
folding via sextuple photocyclization to give a [16]helicene core in a single step. The phenylene and naphthylene units are arranged in the precursor such that unfavorable side reactions (anthracene or benzoperylene formation) are avoided, and this is the key to the success of the one‐step synthesis of [16]helicene, which is the longest [n]helicene that has been synthesized to date.
Multiply charged anions from molecules with extended π-systems
作者:Rainer Schenk、Klaus Müllen、Olof Wennerström
DOI:10.1016/s0040-4039(00)88569-x
日期:1990.1
been prepared by alkali metal reduction of molecules built from benzene rings joined by vinylene groups. Thus, a tetra(stilbenyl)ethylene can be reduced to an octaanion and a [28]paracyclophaneoctaene to three different anions, assigned as the tetra-, hexa-, and octaanion, respectively. The hexaanion, a cyclic 54 π-electron system, is diatropic.
Syntheses, Spectroscopic Properties, and Computational Study of (<i>E</i>,<i>Z</i>)-Ethenyl and Ethynyl-Linked BODIPYs
作者:Guanyu Zhang、Ning Zhao、Petia Bobadova-Parvanova、Maodie Wang、Frank R. Fronczek、Kevin M. Smith、M. Graça H. Vicente
DOI:10.1021/acs.jpca.8b05149
日期:2018.8.2
crystallography. The spectroscopic properties for this series of dimers were investigated in tetrahydrofuran solutions, and very similar absorption and emission profiles were observed for all dimers. Density functional theory calculations show minimal conjugation between the two BODIPY units in the dimers, as a result of the large dihedral angle between the BODIPYs and the linker. The (E)-ethenyl-linked dimer 1a
通过吡咯与相应的双苯甲醛缩合,然后氧化和硼络合,可以合成23-34%的一系列(E,Z)-乙烯基和乙炔基连接的硼二吡咯亚甲基(BODIPY)二聚体。BODIPY二聚体的特征在于1 H,13 C和11 B NMR光谱,高分辨率质谱,在1b,2和3的情况下,通过X射线晶体学。在四氢呋喃溶液中研究了该系列二聚体的光谱性质,并且观察到所有二聚体的吸收和发射曲线非常相似。密度泛函理论计算显示,由于BODIPY和连接基之间的大二面角,二聚体中两个BODIPY单元之间的共轭最小。(E)-乙烯基连接的二聚体1a在本研究中研究的所有二聚体中显示出最高的荧光量子产率。