A series of donor-acceptor pretzelanes has been synthesized, using self-assembly and template-directed protocols, and the dynamic processes that these pretzelanes undergo have been investigated in solution. These compounds exist as libraries of diastereoisomers as a result of their multiple stereoelements, which are dynamically interconverted by several different, in some cases competing, processes. Altering the structure of the pretzelanes changes the rates and mechanisms by which these diastereoisomers equilibrate. Additionally, inserting an element of fixed chirality allows the equilibrium to be biased, while maintaining the barrier to the equilibration processes. These results bode well for the future construction of molecular devices based on switchable diastereoisomerism involving metastable states.
Donor-Acceptor Pretzelanes and a Cyclic Bis[2]catenane Homologue
作者:Yi Liu、Paul A. Bonvallet、Scott A. Vignon、Saeed I. Khan、J. Fraser Stoddart
DOI:10.1002/anie.200500041
日期:2005.5.13
Sn(IV) Porphyrins as NMR Shift Reagents and Supramolecular Protecting Groups: Preparation of a Carboxylate−Catenane Porphyrin Complex
作者:Yin Tong、Darren G. Hamilton、Jean-Christophe Meillon、Jeremy K. M. Sanders
DOI:10.1021/ol990891j
日期:1999.11.1
Coordination of a carboxylic acid diaryl crown ether to a Sn(IV) porphyrin promotes its ability to act as a template for the formation of a [2]catenane: in the absence of the porphyrin the acid-crown yields only a tiny amount of the interlocked derivative, Once isolated the free acid-[2]catenane presents extremely broad resonances in its 500 MHz H-1 NMR spectrum, but complexation to a Sn(IV) porphyrin results in dramatic resolution via a combination of dynamic and dispersive effects.
Dynamic Chirality in Donor−Acceptor Pretzelanes
作者:Y. Liu、S. A. Vignon、X. Zhang、P. A. Bonvallet、S. I. Khan、K. N. Houk、J. F. Stoddart
DOI:10.1021/jo051430g
日期:2005.11.1
A series of donor-acceptor pretzelanes has been synthesized, using self-assembly and template-directed protocols, and the dynamic processes that these pretzelanes undergo have been investigated in solution. These compounds exist as libraries of diastereoisomers as a result of their multiple stereoelements, which are dynamically interconverted by several different, in some cases competing, processes. Altering the structure of the pretzelanes changes the rates and mechanisms by which these diastereoisomers equilibrate. Additionally, inserting an element of fixed chirality allows the equilibrium to be biased, while maintaining the barrier to the equilibration processes. These results bode well for the future construction of molecular devices based on switchable diastereoisomerism involving metastable states.
Flexible self-assembling porphyrin supramolecules
作者:Ken D. Johnstone、Kentaro Yamaguchi、Maxwell J. Gunter
DOI:10.1039/b506987d
日期:——
The design and chemical synthesis of a series of hybrid flexible self-assembling supramolecules utilising both crown ether–naphthalene diimide host–guest chemistry and metalloporphyrin–pyridyl coordination is discussed. The resulting compound structures and dynamics are probed using a variety of techniques, including diffusion ordered NMR spectroscopy (DOSY) and cold-spray ionisation mass spectrometry (CSI-MS).