Chiral Softballs: Synthesis and Molecular Recognition Properties
作者:José M. Rivera、Tomás Martín、Julius Rebek
DOI:10.1021/ja004080i
日期:2001.6.1
dimeric softball chiral although the monomer itself is achiral. The dimers represent capsules with dissymmetric cavities with volumes ranging from 190 to 390 A(3). The cavities are distorted spheres, and asymmetric guests, such as naturally occurring terpenes, generally prefer one enantiomer of the capsule to its mirror image. The selectivities are moderate (up to 4:1). The complexation studies show that
The synthesis of the title compound, a triple-layered cyclophane, is described. The unusually strained structure was supported by its 1H NMR spectra, electronic spectra, and X-ray crystallographic analysis.
描述了标题化合物(三层环烷)的合成。其 1H NMR 光谱、电子光谱和 X 射线晶体学分析支持了异常应变的结构。
Redox responsive molecular tweezers with tetrathiafulvalene units: synthesis, electrochemistry, and binding properties
作者:Maciej Skibiński、Rafael Gómez、Enno Lork、Vladimir A. Azov
DOI:10.1016/j.tet.2009.10.052
日期:2009.12
Several new molecular tweezers with tetrathiafulvalene (TTF) arms as well as mono-TTF derivatives bearing 3,5-di-tert-butylbenzylthio groups to provide enhanced solubility were prepared starting from a bis-cyanoethyl-protected tetrathiafulvalene derivative. The X-ray crystallographic analysis of 3 and 7a showed highly distorted TTF groups and absence of close TTF-TTF contacts in the crystalline state. Comparative cyclic voltammetry (CV) measurements demonstrated that through space distance-dependent TTF-TTF interactions take place in the TTF-containing molecular tweezers, leading to electronic pairing with formation of mixed valence [TTF](2)(+center dot) species and splitting of the first oxidation wave. TTF-containing molecular tweezers were successfully tested as receptors for several electron-deficient substances. (C) 2009 Elsevier Ltd. All rights reserved.
Triple-layered [2.2]naphthalenophane
作者:Tetsuo Otsubo、Fumio Ogura、Soichi Misumi
DOI:10.1016/s0040-4039(00)94024-3
日期:1983.1
Synthesis and Self-Assembly of Pseudo-Spherical Homo- and Heterodimeric Capsules
作者:Carlos Valdes、Urs P. Spitz、Leticia M. Toledo、Stefan W. Kubik、Julius Rebek
DOI:10.1021/ja00156a010
日期:1995.12
Experimental details are given for the synthesis and characterization of several new molecules capable of self-assembly. The new molecules feature glycoluril subunits held apart by various rigid spacers, ethylene (2), naphthalene (3), and ethenoanthracene (4), and assemble through hydrogen bonds into pseudo-spherical dimeric capsules. The nature of their assembly is demonstrated by the X-ray crystal structure of capsules 1.1. The capsules are shown to enclose smaller guest molecules in a reversible manner. Direct evidence of the guest molecules inside the capsules from NMR is presented. In addition to self-assembling dimerically, these new molecules are shown to disproportionate into hybrid species or heterodimers. The resulting new capsules feature internal cavities of varying sizes and shapes. Formation of hybrid dimers 1.2, 1.4, and 3.4 is observed in solutions containing mixtures of two homodimers. The dispropoaionation equilibria could be manipulated by the addition of appropriately sized solvents as guests. Even the energetically unlikely hybrids 1.4 and 3.4 are found to be the dominant species when suitable guests such as CDBr3 are present. Evidence of the existence of the heterodimers is presented from NOE measurements. Factors controlling the heterodimerization are discussed.