Induced Circular Dichroism of Jet-Cooled Phenol Complexes with (R)-(-)-2-Butanol

Abstract

The induced circular dichroism (ICD) of phenol complexed with (R)-(-)-2-butanol [PhOH-(-)BOH] in a supersonic jet is investigated using resonant two-photon ionization circular dichroism (R2PICD) spectroscopy. The R2PICD spectrum of PhOH-(-)BOH exhibits nonzero ICD bands near the absorption region of bare PhOH, where (-)BOH is transparent. Two different conformers containing a single hydrogen bond between PhOH and (-)BOH are identified using ultraviolet-ultraviolet hole-burning and infrared ion-dip spectroscopy combined with quantum theoretical calculations. The ICD values of the two conformers are similar to each other. To understand these similar ICD effects of the conformers, the geometrical asymmetry of the PhOH moiety bound to (-)BOH and the coupling strength of the electric transition dipole moments between PhOH and (-)BOH are estimated. Comparing the ICD values of PhOH (-)BOH with those of PhOH-(-)-L-methyl lactate in the previous report [Hong, A.; et al. J. Phys. Chem. Lett.2018, 9, 476-480], we investigate the physical properties that may govern the differences of the ICD values between the two complexes.