An Adjacent Dibenzotetraazaporphyrin:  A Structural Intermediate between Tetraazaporphyrin and Phthalocyanine

Abstract

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. With the expansion of the pi-system, the first reduction potential does not change significantly, while the first oxidation potential shifts negatively, indicating that the LUMO level remains almost constant while the HOMO level destabilizes significantly. These spectroscopic properties and redox potentials were reproduced by molecular orbital calculations within the framework of the Pariser-Parr-Pople approximation. Thermogravimetry analysis suggests that the skeleton of the adjacent dibenzotetraazaporphyrin complex decomposes at about 95 degrees lower than that of the tetra-tert-butylated phthalocyanine analogue.

Syntheses and properties of trimethylaminophenoxy-substituted Zn(ii)-phthalocyanines

“…A mixture of 2, 2′-bis(2, 3-dicyano-phenoxy)biphenyl 15 29 (302.3 mg, 0.69 mmol), phthalonitrile 2b (480.0 mg, 1.43 mmol) and zinc acetate (254.7 mg, 1.4 mmol) was dissolved in DMAE (100.0 mL). Two drops of DBN were added and the reaction mixture was refluxed for 15 h. Reaction work-up and purification as described above for 16a gave Boc-protected Pc as a blue solid (94.6 mg, 11.4%), mp > 250 °C.…”

Photophysical properties of a water-soluble adjacently substituted bisnaphthalophthalocyanine

“…Synthesis of tetracarboxyphenoxy bisnaphthalophthalocyanine (3, Scheme 1) was realized by statistical condensation method adopted from literature [8] as reported before [7]. The synthesis of this complex involved mixing 1 and 2 in a ratio of 1:2 and refluxing for 2 hrs in the presence of DBU in 1-pentanol as a solvent (Scheme 1).…”

Synthesis and some spectroscopic properties of tetra-2,3-pyridoporphyrazinatosilicon involving bulky axial ligands

“…Similar trends are also seen for SiPc derivatives. Accordingly, although the thermal stability of macrocycles is known to depend on their type [22], these observations additionally indicate that it is also dependent on the nature of the axial ligands and that, in this particular case, the bis(tri-n-hexylsiloxy) group-linked macrocycles are more stable than those containing bis(n-heptylcarbonyloxy) groups.…”

“…Molecular orbital calculations were performed for the pyrrole proton-deprotonated species within the framework of the Pariser-Parr-Pople (PPP) approximation [26,27], where the parameters and other conditions were exactly the same as those we used in our previous publications [15,16,22]. (OH) 2 SiPyD, 5.…”