The CO2 reduction abilities of rhenium bipyridine (Re(bipy)) have been studied in the past as a potential route for artificial photosynthesis. Rhenium bipyridine photochemically reduces CO2 to CO in high quantum yields. The efficiency of this reaction is dependent on the lifetime of the metal to ligand charge transfer (MLCT) species which is reached when the system is exposed to light. Ligand effects have been noted to change the stability of the MLCT species and the corresponding CO2 reduction potential of the complex. A more stable catalyst is able to regenerate and thus reduce more CO2 than a decomposing catalyst. However, a highly stable excited state results in an arrested complex that will not undergo the reduction mechanism. This research studies the substituent effects on the 4,4 region of Re(4,4'-R-2,2'-bipyridine) (R= Br, OCH3, NO2, tert-butyl, H) to determine if functional group changes at this region would affect the reduction ability and the overall stability of the catalyst. Solutions of the rhenium complex with a sacrificial electron donor (triethanolamine) are tested for CO2 reduction abilities after saturation with CO2. Reduction ability (concentration of CO produced) is determined through GC-MS analysis of the reaction product. The overall stability of the MLCT species is investigated through the analysis of fluorescence and Uv-Vis spectrometry throughout the reduction process.

Ligand effects of Re(4,4'-R-2,2'-bipyridine) on carbon dioxide reduction ability

2019 Spring National Meeting

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