
TY  - JOUR
A1  - Le Fevre, RJW 
A1  - Sousa, JB 
A1  - Werner, RL 
T1  - The stretching frequency of the Azo-group in Formazans
JF  - Australian Journal of Chemistry
JO  - Aust. J. Chem.
Y1  - 1956
VL  - 9
IS  - 2
SP  - 151
EP  - 159
KW  - 
UR  - https://doi.org/10.1071/CH9560151 
N2  - Infra-red spectra between 680 and 1600 cm-1 are recorded for 10 formazans and five copper complexes derived therefrom. A common feature at c. 1450 cm-1 in the formazans is removed by chelation ; it is therefore suggested that 1450 cm-l is the stretching frequency of -N:N- as modified by conjugation and hydrogen-bonding in a system Ar.N:N.CAr:N-. Analogies with keto-enol systems indicate that azo- groups in simpler environments would absorb a&quot; higher frequencies, so that of the two alternatives left open by Le Fèvre, O'Dwyer, and Werner (1953), namely, 1579 or 1406 cm-1, the larger is to be preferred. 
ER  -

