This thesis describes and interprets experiments using two-dimensional infrared spectroscopy (2D-IR) and infrared pump-probe spectroscopy (IPP) as applied to the organometallic catalyst Vaska's complex (VC) and its I2 and O2 adducts (VC-I2 and VC-O2 respectively) in a variety of solvation environments. The IPP observations yield information about the speed of vibrational relaxation and how it changes as the solvent is altered, giving suggestions as to the mechanism of the relaxation of vibrational energy. The 2D-IR experiments give information about the dynamics occurring in the solvation shell of the solute molecules and specifics about the molecular origins of the lineshapes found in linear infrared spectroscopy (FTIR). These studies are presented in light of possible connections between solvent dynamics and chemical reaction rates occurring in those solvents. The solvation dynamics of VC and VC-O2 are characterized by 2D-IR first in 3 neat solvents. 2D-IR spectra were analyzed using the inverse center line slope (CLS) as a representative of the frequency-frequency correlation function (FFCF). The dynamics are compared to previously determined oxidative addition rate constants. Next, an IPP and linear infrared spectroscopic study was performed on VC-I2 and VC-O2 in two different sets of binary solvent mixtures. The vibrational lifetime changes linearly with solvent composition. Evidence that relaxation proceeds directly into the solvent modes is shown. In the third study presented, 2D-IR was performed on the VC-I2 vibrational mode to dissect the linear lineshape into its homogeneous and inhomogeneous contributions in binary solvent mixtures of either chloroform or benzyl alcohol in d6-benzene. The full FFCF was determined. Inhomogeneous dynamics are implicated as the dominant broadening mechanism. Finally, an IPP, 2D-IR, and kinetics study on VC and VC-O2 in binary solvent mixtures of d6-benzene with chloroform and benzyl alcohol is presented. The vibrational lifetimes for VC, in contrast to VC-O2 and VC-I2, show a decrease with increasing mole fraction of the more polar solvent in both sets of mixtures. There is evidence of correlation between the rate constants and the homogeneous linewidth of VC-O2, as well as its inhomogeneous amplitude.
University of Minnesota Ph.D. dissertation.February 2015. Major: Chemistry. Advisor: Aaron Massari. 1 computer file (PDF); xv, 252 pages.
Dynamics, Solvent, and Reactions: Ultrafast Infrared Spectroscopy of Vaska's Complex and its Adducts.
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