Linear free energy relationships of the 13C NMR chemical shifts in 5-(3- and 4-substituted arylazo)-4,6-dimethyl-3-cyano-2-pyridones

Abstract

C NMR data for the corresponding 3-and 4-substituted-2',6'-dimethylazobenzenes and 3-and 4-substituted azobenzenes. A good linear dependence obtained in this way, provided a basis to discuss the influence of the ortho-methyl groups on the degree of coplanarity of azobenzene and pyridone systems, and on the efficiency of transmission of electronic substituent effect from one ring to the other one.