π-Extended phenothiazines with fused pentagons and hexagons

Abstract

While π-conjugation extension represents an effective strategy to expand phenothiazine derivatives, the fusion of pentagonal and hexagonal rings into the phenothiazine core remains underexplored. Herein, we present a new class of π-extended phenothiazines synthesized via a ring-fusion strategy. Their structural and photophysical properties were comprehensively characterized through single-crystal X-ray analysis, UV-vis absorption and emission spectroscopy, electrochemical measurements, and computational studies, revealing how π-extension influences their behavior. Additionally, we evaluated the potential of the derivatives as antiproliferative agents, demonstrating their promise for biomedical applications.