Rate constants for thermal cis-to-trans isomerization of N-(phenylazo)-substituted nitrogen ring heterocyles were determined as a function of phenyl ring substitution, cyclic amine ring size, and organic solvents. Observed first-order rate constants are found to increase with increasing electron-withdrawing character of the para substituent, with larger amine rings, and with increasing solvent polarity. Overall, trends observed are consistent with ...
