Chiral differentiation of D- and L-alanine by permethylated β-cyclodextrin: IRMPD spectroscopy and DFT methods

초록

The gaseous chiral differentiation of alanine by permethylated beta-cyclodextrin was studied using IRMPD spectroscopy and density functional theory calculations. The protonated non-covalent complexes of permethylated beta-cyclodextrin and D- or L-alanine were mass-selected and investigated by IR laser pulses in the wavelength region of 2650-3800 cm(-1). The remarkably different features of the IRMPD spectra for D- and L-alanine are described, and their origin is elucidated by quantum chemical calculations. We show that the differentiation of the experimentally observed spectral features is the result of different local interactions of D- and L-alanine with permethylated beta-cyclodextrin. We also assign the extremely high-frequency ( 43700 cm(-1)) bands in the observed spectra to the stretch motions of completely isolated alanine -OH groups.

키워드