Synthesis and characterization of two [2]catenanes based on phenylene-diacetylene crown ethers
Mu-juan Chen , Song-gen Zhou , Mei Li , Chun-yan Lei , Rui Xiao , La-sheng Jiang
Chemical Research in Chinese Universities ›› 2013, Vol. 29 ›› Issue (6) : 1094 -1097.
Synthesis and characterization of two [2]catenanes based on phenylene-diacetylene crown ethers
Two charged donor-acceptor [2]catenanes were synthesized by the cyclization of the π-acceptor 1,1′-[1, 4-phenylenebis-(methylene)]bis(4,4′-bipyridinium)bis(hexafluorophosphate)(2) and bis(bromomethyl)benzene with the templates of the π-donor phenylene-diacetylene crown ethers 1a and 1b in the yields of 31%, 35%, respectively. The mass spectra, 1H and 13C NMR spectra confirm that the phenylene-diacetylene crown ethers, with a nonaromatic π-system, successfully template the cyclization of CBPQT4+. The X-ray crystallography analysis shows that the CBPQT4+ ring encircles around the phenylene motif of the crown ethers, leaving the 1,3-butadiyne fragment out of the cavity of CBPQT4+ ring. The mechanically interlocked structure of [2]catenanes was stabilized by the cooperative effects of π-stacking and hydrogen bonding interactions.
[2]Catenane / Crystal structure / Crown ether
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