Intermolecular hydrogen bonding effect on the VA and VCD spectra: Experimental and DFT studies of lactic acid in water and in methanol

PHYS 561

Martin Losada,, Department of Chemistry, University of Alberta, 11227 Saskatchewan Drive, Edmonton, AB T6G 2G2, Canada and Yunjie Xu,, Department of Chemistry, University of Alberta, Edmonton, AB T6G 2G2, Canada.
Understanding the structure, stability and formation of intermolecular hydrogen bonded complexes involving chiral molecules is of crucial importance in life sciences. In this work, vibrational absorption (VA) and vibrational circular dichroism (VCD) spectroscopic techniques were used to probe the solute-solvent H-bonding interactions of lactic acid-water and lactic acid-methanol in solution.

Geometry optimizations were carried out for both lactic acid-(water)n and lactic acid-(methanol)n complexes, with n = 1, 2, 3, using both B3LYP and B3PW91 functionals with the 6-311++G(d,p) basis set. Detailed spectral simulations were performed in order to understand the dependence of the VA and VCD spectra on the specific binding characters and on the relative stability of the conformers. Three solvent models were exploited to evaluate solvent effects, a pure implicit continuum approach, a explicit model (limited to three solvent molecules), and a combined one.


General Posters
7:30 PM-10:00 PM, Wednesday, March 28, 2007 Hyatt Regency Chicago -- Riverside Center, Poster

Division of Physical Chemistry

The 233rd ACS National Meeting, Chicago, IL, March 25-29, 2007