Date of Award
Chemistry and Biochemistry
Strong photoinduced oxidants are important to organic synthesis and solar energy conversion to chemical fuels or electric. For these applications, visible light absorption is important to solar energy conversion and long-lived excited states are needed to drive catalysis. With respect to these desirable qualities, a series of five 5,6-dicyano[2,1,3]benzothiadiazole ((CN)2BTD) dyes are examined as organic chromophores that can serve as strong photooxidants in catalytic systems. The series utilizes a ((CN)2BTD) core with aryl groups on the periphery varying electron donation strengths relative to the core. The dyes are studied via both steady-state and transient absorption and emission studies. Additionally, computational analysis, voltammetry, crystallography, and absorption spectroelectrochemistry are also used to better understand the behavior of these dyes. Ultimately, a stronger photooxidant than Fukuzumi's acridinium catalyst is arrived at with an exceptionally long excited state lifetime for an organic chromophore of 16 µs. These properties suggest the longest-lived excited state photosensitizer is well-suited for use in catalysis, and visible light driven water oxidation is demonstrated using a water-soluble version of this photosensitizer.
Li, Ivy, "Dicyanobenzothiadiazole-based Organic Dye as a Visible Light Absorbing Strong Photoinduced Oxidant with a 16 Microsecond Long-Lived Excited State" (2022). Honors Theses. 2477.
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