Absorption spectra and molecular structure

Summary

• 1. The absorption spectra of solutions of mono-, di-, tri-, and tetra-chloro derivatives of the phenylhydrazone of 9-acridinecarboxaldehyde hydrochloride in alcoholic hydrogen chloride were investigated.

• 2. It was shown that with respect to the hypsochromic effects of their halogen atoms, the monochloro derivatives fall into the sequence corresponding to the demands of the inductive effect of the substituent.

• 3. The presence of the substituents has little effect on the general shape of the curve and the positions of the short-wave absorption maxima. As the number of substituents increases, there is a regular displacement of the principal absorption maximum in the direction of the short waves. The effects of the substituents are approximately additive.

• 4. It can be inferred from the behavior of the chlorine derivatives of the phenylhydrazone of 9-acridine-carboxaldehyde hydrochloride that complete additivity of the effects of substituents is practically never observed. This fact is to be attributed to the mutual effects of atoms.

• 5. Nine new chloro derivatives of 9-acridinecarboxaldehyde phenylhydrasome were prepared.