An Adjacent Dibenzotetraazaporphyrin: A Structural Intermediate between Tetraazaporphyrin and Phthalocyanine.

An adjacent dibenzotetraazaporphyrin, in which two benzene units are fused to the adjacent pyrrole rings of tetraazaporphyrin skeleton, has been synthesized as a copper complex for the first time and characterized by electronic absorption and magnetic circular dichroism spectroscopy, by cyclic voltammetry and spectroelectrochemistry using an optically transparent thin layer electrochemical cell. The results were compared with those of tetraazaporphyrin and phthalocyanine analogues. The title compound shows intermediate characteristics between those of normal tetraazaporphyrins and phthalocyanines; the Q-band shifts to the red and becomes more intense while the Soret band broadens with increasing the size of the pi-system.