Infrared spectroscopy azobenzenes

Hamm, R, Ohline, S. M., and Zinth, W. (1997). Vibrational cooling after ultrafast photoisomerization of azobenzene measured by femtosecond infrared spectroscopy. /. Chvm. P ys. 106, 519-529. 

Langmuir-Blodgett Films of Azobenzene-Containing Long Chain Fatty Acids and Their Salts Studied by Ultraviolet-visible and Infrared Spectroscopy. Langmuir 10, 236i (1994). 

Sato, X, Ozaki, Y., and Iriyama, K. Molecular a r laon and photoisomerization of Laiigmuir-Blodgett-fihns of azobenzene-containing long-diain fatty-acids and tiieir salts studied by ultraviolet-visible and infrared spectroscopies. 1994, 10, 2363-2369. 

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... 

When the potential was scanned to 0 mV, a pair of waves due to the redox of the azobenzene moiety appeared, in addition to that of ferrocene in the first potential scan (sohd line in Fig. 13c). The wave due to the redox of azobenzene, however, disappeared, and the redox potential and the peak separation of the redox wave due to ferrocene became more negative and smaller, respectively, in the second scan (dotted line in Fig. 13c). The redox potential and the peak separation returned to the original values after UV irradiation. These changes in the electrochemical characteristics of the latter electrode were reversible. On the basis of the structural analysis results by in situ Fourier-transform infrared reflection absorption spectroscopy (FT-IRRAS), we concluded that the electrochemical properties, that is, the redox potential and the charge transfer rate, of the ferrocene group in the SAM-modified gold electrode can be reversibly controlled... 

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