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DOI: 10.1039/A903120K (Paper) Reference Section for: J. Chem. Soc., Perkin Trans. 2, 1999, 1569-1576

Molecular engineering. Part 5.1 Tuning the constrictive binding of container host by the atomic order of portal pillars

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Chaesang Ihm, Minkyu Kim, Hyejae Ihm and Kyungsoo Paek

Abstract

Two D4h container hosts 12 and 13 with 4(CH2–O–bridge–O–CH2) portal pillars were obtained in good yields by stepwise synthetic routes and showed complementary complexation behaviors to their analogues with (O–CH2–bridge-CH2–O)4 portal pillars. 1H NMR spectral chemical shifts of host’s inward-turned OCH2O protons were sensitive to guest change. The stability orders of hemicarceplexes were 12–p-(CH3CH2)2C6H4 > 12–p-(CH3O)2C6H4 [double greater-than, compressed] 12–o-(CH3O)2C6H4 > 12–m-(CH3O)2C6H4 and 13–CH3COCH2CH3 > 13–CH3COCH2CH(CH3)2 > 13–CH3CON(CH3)2 > 13–CH3COOCH2CH3 > 13–CH3CH2CON(CH3)2 in terms of the activation energy barrier for decomplexation. Large solvent effects on the activation energy for decomplexation of hemicarceplexes were observed.

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