Structural Dynamics of a Catalytic Monolayer Probed by Ultrafast 2D IR Vibrational Echoes.

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Bibliographic Details
Title:	Structural Dynamics of a Catalytic Monolayer Probed by Ultrafast 2D IR Vibrational Echoes.
Authors:	Rosenfeld, Daniel E., Gengeliczki, Zsolt, Smith, Brian J., Stack, T. D. P., Fayer, M. D.
Source:	Science (pre-March 2025). 11/4/2011, Vol. 334 Issue 6056, p634-639. 6p.
Subjects:	Structural dynamics, Infrared spectroscopy, Carbonyl compounds, Vibrational spectra, Ultrashort laser pulses, Monomolecular films
Abstract:	Ultrafast two-dimensional infrared (2D IR) vibrational echo spectroscopy has proven broadly useful for studying molecular dynamics in solutions. Here, we extend the technique to probing the interfacial dynamics and structure of a silica surface-tethered transition metal carbonyl complex-tricarbonyl (1,10-phenanthroline)rhenium chloride-of interest as a photoreduction catalyst. We interpret the data using a theoretical framework devised to separate the roles of structural evolution and excitation transfer in inducing spectral diffusion. The structural dynamics, as reported on by a carbonyl stretch vibration of the surface-bound complex, have a characteristic time of -150 picoseconds in the absence of solvent, decrease in duration by a factor of three upon addition of chloroform, and decrease another order of magnitude for the bulk solution. Conversely, solvent-complex interactions increase the lifetime of the probed vibration by 160% when solvent is applied to the monolayer. [ABSTRACT FROM AUTHOR]
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Database:	Psychology and Behavioral Sciences Collection

Description
Abstract:	Ultrafast two-dimensional infrared (2D IR) vibrational echo spectroscopy has proven broadly useful for studying molecular dynamics in solutions. Here, we extend the technique to probing the interfacial dynamics and structure of a silica surface-tethered transition metal carbonyl complex-tricarbonyl (1,10-phenanthroline)rhenium chloride-of interest as a photoreduction catalyst. We interpret the data using a theoretical framework devised to separate the roles of structural evolution and excitation transfer in inducing spectral diffusion. The structural dynamics, as reported on by a carbonyl stretch vibration of the surface-bound complex, have a characteristic time of -150 picoseconds in the absence of solvent, decrease in duration by a factor of three upon addition of chloroform, and decrease another order of magnitude for the bulk solution. Conversely, solvent-complex interactions increase the lifetime of the probed vibration by 160% when solvent is applied to the monolayer. [ABSTRACT FROM AUTHOR]
ISSN:	00368075
DOI:	10.1126/science.1211350