Organometallic Triazoles with Phototunable Properties as Cytotoxic Agents for Potential Anticancer Applications

The creation of organometallic–organic hybrid molecules opens the way to the creation of biologically active molecules with a broad spectrum of activity. To simplify the creation of such compounds, it is necessary to establish structure–activity relationships and physicochemical property–activity relationships. 1,2,3-Triazoles containing a cymantrenylalkyl or ferrocenylalkyl moiety were investigated in this work. Studies of the photophysical properties revealed that fluorescence was most influenced by the viscosity of the medium and the formation of aggregates. The redox properties of 1,2,3-triazoles were determined by the organometallic moiety and its position in the heterocyclic ring. Experimental and theoretical studies showed that the organometallic moiety played a key role in varying the electronic properties and reactivity of 1,2,3-triazoles. Only cymantrene derivatives exhibited photochemical activity, and photolysis resulted in the formation of stable chelate complexes with a Mn–N2 bond in the heterocycle. It is worth noting that the chelates were the most reactive and underwent oxidation most readily. Studies on the antitumor activity of 1,2,3-triazoles showed that 1-cymantrenylethyl-4-phenyl-1,2,3-triazole (4) exhibited the highest cytotoxicity in the dark (A549 (CC50 = 9.0 ± 0.6 µM) and HCT116 (CC50 = 15.9 ± 2.2 µM)), whereas the effect of irradiation was inconsistent and depended on the incubation time. Thus, this study opens the way for the rational design of biologically active molecules based on phototunable organometallic compounds.