Chemistry Seminar with Dr. Michael Walter from the University of North Carolina at 4:00pm

Abstract: Thiazolo[5,4-d]thiazoles (TTzs) are attractive materials for a variety of photochemical and electrochemical applications due to their simple syntheses, strong fluorescence, and high chemical stability. The unique fused, bicyclic TTz molecular structure enables multifunctional properties, high-performance fluorescence sensing, anolyte materials for redox-flow batteries, and as efficient photocatalysts. Dipyridinium, extended-viologen TTz derivatives exhibit high fluorescent quantum yields (> 90%) and reversible electrochromic properties. Simple TTz chromogenic hydrogel devices display electrochromism, electrofluorochromism, and photochromism and exhibit excellent reversibility and stable fluorescence cycling. We have also shown the ability of alkylated dipyridinium TTzs to drive the formal addition of potassium organotrifluoroborates (alkyl-BF3K) to imines with good efficiencies (isolated yields ~ 80-90%) and turnover numbers (TON, 400-700), using surprisingly low mol% (0.05-0.1) photocatalyst. Newly designed, asymmetrically substituted, push-pull TTz materials show strong solvatofluorochromism and are being evaluated as voltage-sensitive dyes for cell membrane potential sensing. Asymmetric TTzs can be used as a cell membrane VSD and have shown good cell membrane localization, insignificant cytotoxicity, and photostabilities that are 4 times higher than comparable dyes. Presented is the recent work covering these high-performance applications and current studies of TTz chromophores for efficient for solid-state fluorescence sensing, photoinduced electron transfer, photochromism, and related solar applications.