Alpha-naphtholbenzein

Synthesis of Phthalocyanine Compounds Containing α-Naphtholbenzene Units

Özçeşmeci M. Journal of Organometallic Chemistry, 2014, 767: 16-21.

Alpha-naphtholquinone is a pH indicator that changes color when a neutral solution becomes alkaline. The precursors required for the synthesis of phthalocyanine complexes can be prepared through the nucleophilic aromatic substitution reaction between 4-nitrophthalonitrile and α-naphtholbenzene.
Synthetic procedure of phthalocyanine complexes
·α-Naphtholbenzein (1.081 g, 2.890 mmol) and 4-nitrophthalonitrile (0.500 g, 2.890 mmol) were stirred and dissolved in 50 mL dry DMF at room temperature.
· Anhydrous K2CO3 (0.800 g, 5.780 mmol) was added portionwise over 2 h under a nitrogen atmosphere, then the reaction mixture was stirred vigorously for further 3 days. After the reaction was completed, the mixture was purified to obtain compound 1.
· Cyclotetramerization reactions of the new dinitrile derivative were accomplished in dry dimethylformamide at refluxed temperature. Then metal-free phthalocyanine (2) and zinc(II) phthalocyanine (3) were prepared respectively.