Polymerization of Nitro Compounds on Silver Surfaces During Surface-Enhanced Raman Scattering
Abstract
Surface-enhanced Raman scattering was observed from thin films formed by 1,4- and 1,3-dinitrobenzene spin-coated onto silver island films from dilute solutions. During laser irradiation of 1,4-DNB films on silver substrates at relatively high laser powers, new bands appeared near 1152, 1350, 1412, and 1460/cm and bands near 1118, 1358, and 1372/cm decreased in intensity. A band near 1598/cm shifted to near 1605/ cm. The bands near 1152 and 1412/ cm were assigned to stretching modes of Phi-N and -N=N- bonds of azo compounds, respectively, indicating that polymerization of 1,4-DNB had occurred. The extent of polymerization was greatest when the surface coverage of adsorbed 1,4-DNB was greatest and when the SERS experiments were carried out in a nitrogen atmosphere, indicating that reducing conditions were required for the polymerization. No polymerization was observed for 1,3-DNB under similar circumstances. The difference was attributed to orientation of the adsorbed species. Thus, it was concluded that 1,4-DNB was adsorbed with a horizontal configuration in which the aromatic rings were parallel to the substrate surface and both nitro groups were in contact with the surface while 1,3-DNB was adsorbed with a vertical configuration in which the rings were perpendicular to the surface and only one nitro group was in contact with the surface.
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 01, 1989
- Accession Number
- ADA216116
Entities
People
- F. James Boerio
- G. Montaudo
- S. J. Clarson
- W. H. Tsai
Organizations
- University of Cincinnati