Synthesis, spectroscopy, and quantum-chemical calculations on 1-substituted phenyl-3,5-diphenylformazans.

In this study 1-substituted phenyl-3,5-diphenylformazans were synthesized from benzaldehyde-N-phenylhydrazone and appropriate phenyldiazonium salts having CH(3), Br, and Cl at the o-, m-, and p-positions of 1-phenyl ring. Their structures were determined by infrared and ultraviolet-visible spectra. Bathochromic effect in accordance with the electron-donating effect of CH(3), Br, and Cl group and its magnitude were dependent upon type and position of substituent on the ring. The ground-state geometries and absorption wavelengths for 1-phenyl substituted formazans were studied with density functional theory and time-dependent density functional theory. The calculations were carried out by using PBE1PBE functional with 6-311G(2d,2p) basis set for lambda(max) of the UV-vis spectra for the studied formazans. A good agreement was obtained between the experimental and computed values.