Raman spectroscopy azobenzenes

Gao, P., Gosztola, D. and Weaver, M.J. (1988) Surface-enhanced Raman spectroscopy as a probe of electroorganic reaction pathways. 1. Processes involving adsorbed nitrobenzene, azobenzene, and related species. The Journal of Physical Chemistry, 92, 7122-7130. 

The biaxial orientation in photoaddressable azobenzene films has been observed recently by polarized Raman spectromicroscopy [64]. Here, IR spectroscopy has been advantageously used as a complementary technique to measure the order... 

The relevant vibrations for this review are the N=N and C-N (Ph-N) stretching vibrations and, perhaps, torsional vibrations around the C-N bond. The E-azobenzene molecule has a center of inversion, and therefore the N=N vibration is infrared-inactive, but Raman-active, and has been found to be at 1442 cm". By IR spectroscopy, Kiibler et al. located the symmetric C-N stretching vibration at 1223 cm" in E- and at 866 cm in Z-azobenzene. The N=N vibration in Z-azobenzene is at 1511 cm" (in KBr pellets). These numbers are confirmed by newer work Biswas and Umapathy report 1439 and 1142 cm for the N=N and C-N vibrations (in CCE), and Fujino and Tahara found nearly identical results (1440 cm" and 1142 cm ). A thorough vibrational analysis of the E-isomer is given by Amstrong et al. The vibrations in the (n,7t ) excited state are very similar 1428 cm" and 1130 cm"h... 

The relevant vibrations for this review are the N=N and C-N (Ph-N) stretching vibrations and, perhaps, torsional vibrations around the C-N bond. The E-azobenzene molecule has a center of inversion, and therefore the N=N vibration is infrared-inactive, but Raman-active, and has been found to be at 1442 By IR spectroscopy, Kiibler et al. located the symmetric... 

The C=C groups show no special features in the IR spectra of Au complexes 62 (item C-4 in Table 2), pointing to the lack of conjugation of these groups with the Au atom. See also Section IV.D.l below. IR spectroscopy was used to elucidate the structure of gold complexes with azobenzene compounds (165-167), including formation of N-metal and C-metal bonds. The resonance Raman spectra of bihrubin (168) and its complexes with Cu(II), Ag(I) and Au(III) show that the complexes have different structures, due to the different ionic charge and ionic radius of the metal ions . 

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