117271-77-9Relevant articles and documents
Enantioselective Limiting Transport into a Fixed Cavity via Supramolecular Interaction for the Chiral Electroanalysis of Amino Acids Regardless of Electroactive Units
Gao, Li,Kong, Yong,Pan, Fei,Tao, Yongxin,Wu, Datong
, p. 13711 - 13717 (2020/12/01)
Although an increasing number of researchers are developing electroanalytical protocols for the chiral recognition of amino acids, the electroactive units of the tested isomers still need to provide corresponding electrical signals. In this study, a supramolecular system was developed for the chiral electroanalysis of amino acids regardless of electroactive units. As a model system, an enantiopure electroactive molecule Fc-(S,S)-1 that includes a ferrocenyl group was synthesized and acted as a guest. Moreover, hydrophobic cyclobis-(paraquat-p-phenylene) (CBPQT4+-2) was used as the host. In the presence of π-πstacking and the attraction of π-electrons, CBPQT4+-2 can encapsulate Fc-(S,S)-1 into its cavity. Next, a screen-printed electrode was utilized for electrochemical chiral recognition. The host was fixed on the surface of the working electrode, and the guest was used as the electroactive chiral selector to support electron transfer. Once different configurations of amino acids (threonine, histidine, glutamine, and leucine) were mixed with the guest, regardless of whether they contained electroactive units, differences in the cyclic voltammetry results of the probe enantiomers could be observed, namely, in the peak currents or peak potentials. However, glutamine was an exception because the L-isomer had a stronger binding affinity with Fc-(S,S)-1 + Cu(II), which would limit the transport of the complex into the cavity of CBPQT4+-2, thereby resulting in a low peak current. Thus, an inverse phenomenon was observed with glutamine. In summary, we believe that this work can increase the testing scope for the chiral recognition of different kinds of isomers using electrochemical tools.
Synthesis of ExnBox cyclophanes
Barnes, Jonathan C.,Juricek, Michal,Vermeulen, Nicolaas A.,Dale, Edward J.,Stoddart, J. Fraser
, p. 11962 - 11969 (2014/01/06)
A rapid and efficient synthesis of the extended bipyridinium-based class of cyclophanes - that is, ExnBox4+ (n = 0-3), where n is the number of p-phenylene rings inserted between the pyridinium rings - is demonstrated, resulting in much higher yields of products along with a reduced output of oligomeric byproducts. Although each cyclophane can be synthesized readily without the use of a precise stoichiometric amount of template, ExBox4+ can be prepared in 66% yield (following crystallization) using six equivalents of pyrene in a template-directed protocol. This new methodology has been employed to synthesize, in modest yield, a nearly 2.5 nm long cyclophane consisting of 12 aromatic rings.
Redox-responsive reverse vesicles self-assembled by pseudo[2]rotaxanes for tunable dye release
Zhang, Kang-Da,Zhou, Tian-You,Zhao, Xin,Jiang, Xi-Kui,Li, Zhan-Ting
, p. 14839 - 14844,6 (2012/12/12)
Reverse vesicles exhibiting functions similar to those of normal vesicles have been constructed through the self-assembly of TTF/CBPQT4+-based pseudo[2]rotaxanes in a nonpolar solvent. The ends of the threads of the pseudo[2]rotaxanes are attached with a Frechet-type G-3 dendron and a hydrogen-bonded arylamide foldamer. These vesicles exhibit a response to redox. By exploiting the dynamic feature-spontaneously slow disassociation of the pseudorotaxanes-the sustained release of dyes embedded in the reverse vesicles has been demonstrated, which can be further tuned by changing the solvent polarity.
