A Bistable Poly[2]catenane Forms Nanosuperstructures
作者:Mark A. Olson、Adam B. Braunschweig、Lei Fang、Taichi Ikeda、Rafal Klajn、Ali Trabolsi、Paul J. Wesson、Diego Benítez、Chad A. Mirkin、Bartosz A. Grzybowski、J. Fraser Stoddart
DOI:10.1002/anie.200804558
日期:2009.2.23
Side‐chain poly[2]catenanes at the click of a switch! A bistable side‐chain poly[2]catenane has been synthesized and found to form hierarchical self‐assembled hollow superstructures of nanoscale dimensions in solution. Molecular electromechanical switching (see picture) of the material is demonstrated, and the ground‐state equilibrium thermodynamics and switching kinetics are examined as the initial
作者:Megan M. Boyle、Jeremiah J. Gassensmith、Adam C. Whalley、Ross S. Forgan、Ronald A. Smaldone、Karel J. Hartlieb、Anthea K. Blackburn、Jean-Pierre Sauvage、J. Fraser Stoddart
DOI:10.1002/chem.201202070
日期:2012.8.13
AbstractA trans isomer of a figure‐of‐eight (Fo8) compound was prepared from an electron‐withdrawing cyclobis(paraquat‐p‐phenylene) derivative carrying trans‐disposed azide functions between its two phenylene rings. Copper(I)‐catalyzed azide–alkyne cycloadditions with a bispropargyl derivative of a polyether chain, interrupted in its midriff by an electron‐donating 1,5‐dioxynaphthalene unit acting as the template to organize the reactants prior to the onset of two click reactions, afforded the Fo8 compound with Ci symmetry. Exactly the same chemistry is performed on the cis‐bisazide of the tetracationic cyclophane to give a Fo8 compound with C2 symmetry. Both of these Fo8 compounds exist as major and very minor conformational isomers in solution. The major conformation in the trans series, which has been characterized by X‐ray crystallography, adopts a geometry which maximizes its CH⋅⋅⋅O interactions, while maintaining its π⋅⋅⋅π stacking and CH⋅⋅⋅π interactions. Ab initio calculations at the M06L level support the conformational assignments to the major and minor isomers in the trans series. Dynamic 1H NMR spectroscopy, supported by 2D 1H NMR experiments, indicates that the major and minor isomers in both the cis and trans series equilibrate in solution on the 1H NMR timescale rapidly above and slowly below room temperature.
Thermodynamic forecasting of mechanically interlocked switches
作者:Mark A. Olson、Adam B. Braunschweig、Taichi Ikeda、Lei Fang、Ali Trabolsi、Alexandra M. Z. Slawin、Saeed I. Khan、J. Fraser Stoddart
DOI:10.1039/b911874h
日期:——
Mechanically interlocked molecular (MIM) switches in the form of bistable [2]rotaxanes and [2]catenanes have proven to be—when incorporated in molecular electronic devices (MEDs) and in nanoelectromechanical systems (NEMS)—a realistic and viable alternative to the silicon chip density challenge. Structural modifications and chemical environment can have a large impact on the relaxation thermodynamics
Photochemical Bromination of 2,5‐Dimethylbenzoic Acid as Key Step of an Improved Alkyne‐Functionalized Blue Box Synthesis**
作者:Ahmad Bachir、Fabiana Ciocchetti、Daniel P. Couto、Simone Di Noja、Cristian Pezzato、Giulio Ragazzon
DOI:10.1002/ejoc.202300498
日期:2023.8
In this work, the synthesis of an alkyne-functionalized blue box has been revised. Overcoming the limits of the existing synthesis for every single step, the overall yield was increased five times. Importantly, photochemical bromination was adopted to obtain a key intermediate. The target compound was functionalized by using click-chemistry, and it was confirmed by electrochemical techniques that it