The Fluorine Effect in Zwitterionic Half-Sandwich Iridium(III) Anticancer Complexes

Area of Science:

• Organometallic Chemistry
• Medicinal Chemistry
• Cancer Biology

Background:

• Fluorine's success in organic anticancer drugs contrasts with limited reports on its role in metal-based complexes.
• Half-sandwich iridium(III) complexes offer a promising scaffold for developing novel anticancer agents.

Purpose of the Study:

• To synthesize and characterize novel half-sandwich zwitterionic iridium(III) complexes with varying substituents.
• To investigate the impact of fluorine substitution on the anticancer activity and mechanism of action of these complexes.

Main Methods:

• Synthesis and characterization of iridium(III) complexes.
• Single-crystal X-ray crystallography for structural determination.
• Evaluation of anticancer activity, lipophilicity, cellular uptake, and mechanism of action (ROS, apoptosis, cell cycle).

Main Results:

• Novel zwitterionic iridium(III) complexes were synthesized and characterized.
• Fluorinated complexes exhibited significantly enhanced anticancer activity compared to non-fluorinated analogs.
• Lipophilicity and cellular uptake were identified as key factors influencing cytotoxicity.
• Mechanism involves energy-dependent cellular entry, lysosomal localization, increased ROS, apoptosis induction, and cell-cycle perturbation.

Conclusions:

• Fluorine substitution is a viable strategy to enhance the anticancer potency of zwitterionic iridium(III) complexes.
• Lipophilicity and cellular uptake are critical determinants of efficacy.
• These complexes represent promising candidates for further development as metal-based anticancer drugs.