Octa- and tetra-substituted phthalocyanines with methoxyeugenol group: synthesis, characterization and in vitro antimicrobial activity

Abstract

In this study, the novel phthalonitrile derivatives 1 and 2 were synthesized. Tetra-substituted metal-free 1a (H₂Pc) and metallophthalocyanines (ZnPc 1b, CoPc 1c and CuPc 1d) bearing four peripheral 4-allyl-2,6-dimethoxyphenol (methoxy-eugenol) groups and octa-substituted metal-free 2a and metallophthalocyanines (ZnPc 2b, CoPc 2c and CuPc 2d) bearing eight peripheral methoxy-eugenol group were synthesized. All new synthesized compounds are characterized by IR, ¹³C{¹H} NMR (for 1 and 2), UV-Vis (for 1a–2d) and mass spectroscopy. Antimicrobial activities of the synthesized phthalonitrile derivatives (1 and 2) and phthalocyanine compounds 1a–2d were determined by microdilution broth method against nine different bacteria and one yeast species. In this study, CoPc (2c) compound, which has eight peripheral 4-allyl-2,6-dimethoxyphenol, had the highest antibacterial activity (minimum inhibitory concentration [MIC] = 312 μg/mL). In addition, 1b, 1d, 2b and 2d were found to be effective on at least three different bacterial species at different concentrations (MIC = 1250–5000 μg/mL). Shigella flexneri were the most affected bacteria, but none of the compounds were effective against fungal isolate.

Graphical Abstract

Keywords:

• Octa-phthalocyanine
• eugenol
• characterization
• metallophthalocyanine
• antimicrobial activity

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

We are grateful to the research fund of Artvin Çoruh University (P.N: 2019.F90.02.02) and the Scientific & Technological Research Council of Turkey (TUBITAK, project no. 118Z578).