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1. A New Cryptand/Paraquat [2]Pseudorotaxane | |||
Shijun Li,Feihe Huang,Lev N. Zakharov,Carla Slebodnick,Arnold L. Rheingold,Harry W. Gibson | |||
Chemistry 20 July 2009 | |||
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Abstract:A new cryptand/paraquat [2]pseudorotaxane and its crown ether analog were synthesized and charac-terized by proton NMR, mass spectrometry, and single crystal X-ray analysis. The Job plots based on proton NMR data demonstrated that both the complex between cryptand 1 and paraquat derivative 2a and the complex between bis(p-phenylene)-34-crown-10 (3) and paraquat derivative 2b have 1:1 stoichiometry in solution. The apparent association constants (Ka,exp) of 1•2a and 3•2b calculated for 1:1 complexes were 1.4 ( 0.2)  104 and 4.7 ( 0.5)  102 M1, respectively. X-ray analysis showed that 1•2a is stabilized by ten hydrogen bonds and face-to-face -stacking interactions in the solid state, while 3•2b is stabilized by four hydrogen bonds and face-to-face -stacking interactions. As well as in the X-ray structure of 1•2c, a water molecule acts as a hydrogen bridge between the -protons of 2a and the ether oxygen atoms of 1 in 1•2a. The successful preparation of 1•2a demonstrated that the tert-butyl group is not big enough to be a stopper for rotaxanes based on 1. | |||
TO cite this article:Shijun Li,Feihe Huang,Lev N. Zakharov, et al. A New Cryptand/Paraquat [2]Pseudorotaxane[OL].[20 July 2009] http://en.paper.edu.cn/en_releasepaper/content/33935 |
2. Complexes of Diquat with Dibenzo-24-Crown-8 | |||
Shijun Li,Feihe Huang,Carla Slebodnick,Mehdi Ashraf Khorassiani,Harry W. Gibson | |||
Chemistry 23 December 2008 | |||
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Abstract:Dibenzo-24-crown-8 (1) and diquat (2) form a 1:1 complex 1? in acetone with Ka = 2.0 X 102 M-1, but yield a crystalline 2:1 Host:Guest inclusion complex 12? as shown by X-ray analysis. | |||
TO cite this article:Shijun Li,Feihe Huang,Carla Slebodnick, et al. Complexes of Diquat with Dibenzo-24-Crown-8[OL].[23 December 2008] http://en.paper.edu.cn/en_releasepaper/content/26877 |
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