Synthesis and optical properties of tetrapyrazinoporphyrazine containing phenylene dendron unit as a peripheral substituent

A dendritic shell can create a distinct micro-environment within its core. It also has the advantage of possessing unique photochemical, photophysical, electrochemical, and catalytic properties. Polyphenylene dendrons, which are characterized by their shape-persistent structures and out-of-plane twisted phenyl components, have previously been successfully attached to various functional groups. We have recently developed a convenient method for synthesizing a new type of porphyrazine that contains both flexible (linear) and more rigid (dendritic) groups. The synthesis of this completely aromatic and dendronic structure is unique in that it is based on a [2+4] Diels-Alder cycloaddition of tetraphenylcyclopentadienone to an ethynyl compound, followed by the elimination of carbon monoxide. In this study, tetrapyrazinoporphyrazinato metal and metal-free complexes were prepared by mixing 2,3-dicyano-5-polyphenylpyrazines with magnesium in n-butanol. The synthesized tetrapyrazinoporphyrazines were characterized by UV-visible spectroscopy, MALDI-TOF-MS (matrix-assisted laser desorption/ionization time-of-flight mass) spectrometry, elemental analysis and 1 H NMR spectroscopy.