Dicyanopyrazine studies. Part VI: Absorption spectra and aggregation behaviour of tetrapyrazinoporphyrazines with long alkyl groups

Tetrapyrazinoporphyrazities with long alkyl groups drastically changed their absorption spectra by molecular aggregation depending on the polarity of solvent and temperature. Tetrapyrazinoporphyrazinato aluminium hydroxide showed red fluorescence with a small Stokes shift indicating less structure changes in the excited state and high efficiency of energy transformation of the absorbed light energy to the fluorescence. These porphyrazines have satisfactory solubility in chlorohydrocarbons, tetrahydrofuran and toluene. The syntheses and characterization of tetrapyrazinoporphyrazines derived from diaminomaleonitrile (DAMN) and phenylglyoxal or 1,2-dicarbonyl compounds with long alkyl groups are described.