Surface-enhanced Raman spectroscopic monitoring of the catalytic oxidation of 4-(dimethylamino)benzaldehyde by gold nanoparticles

PHYS 541

Rachel M. Krieger, and Paul W. Jagodzinski, Department of Chemistry and Geochemistry, Colorado School of Mines, 1400 Illinois St., Golden, CO 80401
Introduction of 4-(dimethylamino)benzaldehyde (DABA) to a solution of gold nanoparticles (gold citrate colloid) results in the catalytic oxidation of DABA to the acid (DABH). The rate of reaction is a function of pH and proceeds much faster in alkaline solution. The aggregation rate of the colloidal particles, which is also a function of pH, combined with the rate of reaction, controls whether surface-enhanced Raman spectra of DABA or DABH are observed. At all measured pH values of the colloidal solution, DABA and/or DABH are adsorbed to the gold surface through the aromatic ring. This results in the dramatic enhancement of signals of the vibrational normal modes with significant contributions from the carbonyl or dimethylamino moieties.

Poster Session
7:30 PM-10:00 PM, Wednesday, 13 September 2006 Moscone Center -- Hall D, Poster

8:00 PM-10:00 PM, Monday, 11 September 2006 Moscone Center -- Hall D, Sci-Mix

Division of Physical Chemistry

The 232nd ACS National Meeting, San Francisco, CA, September 10-14, 2006