Abstract: Mono[2-deoxy-2-(O-p-toluensulfonyl)]-β-cyclodextrin (2-Ots-β-cyclodextrin, compound 1) was substituted with 2-butenedinitrile-2,3-dimercapto sodium salt to give the product mono[2-deoxy-2-(2-butenedinitrile-2,3-dimercapto sodium salt)]-β-cyclodextrin (2-Mnt-β-cyclodextrin, compound 2). Compound 2 was characterized by IR spectroscopy, UV spectroscopy, thermogravimetry, 1H- and 13C-NMR spectroscopy. Different from its isomer mono[6-deoxy-6-(2-butenedinitrile-2,3-dimercapto sodium salt)]-β-cyclodextrin (6-Mnt-β-cyclodextrin) showing splitting Cotton effects via mutual inclusion complexation, 2-Mnt-β-cyclodextrin exhibited the absence of any circular dichroism (CD) signal in solution. In the meantime, quantum chemistry methods (time dependent-density functional theory, TD-DFT) were recruited in assisting assignment and prediction of the CD signals in spectra. Based on both the theoretical approach and experimental data, the different conformations of the two ionized isomers were revealed.

Key words: 2-butenedinitrile-2,3-dimercapto, β-cyclodextrin, circular dichroism, TD-DFT, mutual penetrating model