Our laboratory has a longstanding interest in the development of metal complex photosensitizers for phototherapy applications. We have been particularly focused on Ru(II)- and Os(II)-oligothiophene complexes, with our Ru-based TLD1433 having advanced to Phase 2 clinical trials for treating bladder cancer with PDT. Our approach involves tuning the orbital energy levels of metal complexes to drive the desired excited state photosensitization and photochemical reactions. This is accomplished through rational manipulation of the coligand identities and their substituents. To better understand the exceptional PDT activity of TLD1433 and related analogs, we have examined the effect of thiophene chain length and coligand identity on the excited state dynamics of these metal complex photosensitizers. We are now investigating the absolute energy levels and electrochemical characteristics of these Ru(II)-oligothiophene complexes. Together, the photophysical and electrochemical properties will inform which features and characteristics give rise to the potent PDT effect that we observe from such systems. This study focuses on the effect of CF3 substituents on bipyridyl coligands and thiophene chain length in the [Ru(dtfmbpy)2(IP-nT)]2+ family, where, dtfmbpy is 2,5′-di(triflouromethyl)-2,2′-bipyridine, IP is imidazo[4,5-f][1,10]phenanthroline, and nT is the number of thiophenes (n=0 to 4). In this vein, two complementary electrochemical techniques, cyclic voltammetry (CV) and cyclic differential pulse voltammetry (CDPV), were used in tandem to find the absolute energy levels and electrochemical properties of these metal complex photosensitizers.

Effects of triflouromethyl substitution and thiophene chain length on energy levels and electrochemical characteristics of [Ru(dtfmbpy)2(IP-nT)]2+

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ACS Fall 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.