SURFACE-ENHANCED RAMAN-SPECTROSCOPY OF BIPYRIDINES AND PHENYLPYRIDINES

Raman and SERS spectra in the region 700-3150 cm-1 are reported for 2,2′-, 3,3′-, 4,4′-, 2,3′-, and 2,4′-bipyridines and for 2-, 3-, and 4-phenylpyridines. Spectra for 4,4′-dimethyl-2,2′-bipyridine, 1,10-phenanthroline, and N-methyl-4,4′-bipyridinium are also reported. Comparison of the Raman and SERS spectra, and, in particular, analysis of the C-H stretching frequencies and intensities, indicates that in all cases except 2-phenylpyridine the molecules sit perpendicular to the sol surface consistent with σ donation from the less sterically hindered nitrogen donor atom and an all-planar structure. © 1990 American Chemical Society.