Christoph Kerzig University of Basel
Sensitized triplet-triplet annihilation is the most promising mechanism for pooling the energy of two visible photons, but its applications in solution were so far limited to organic solvents, with a current maximum of the excited-singlet state energy of 3.6 eV. By combining tailor-made iridium complexes with naphthalenes, we demonstrate blue-light driven upconversion in water with unprecedented singlet-state energies approaching 4 eV. The annihilators have outstanding excited-state reactivities enabling challenging photoreductions driven by sTTA. Specifically, we found that an aryl-bromide bond activation can be achieved with blue photons, and we obtained full conversion for the very energy-demanding decomposition of a persistent ammonium compound as typical water pollutant, not only with a cw laser but also with an LED light source. These results provide the first proof-of-concept for the usage of low-power light sources for challenging reactions employing blue-to-UV upconversion in water, and pave the way for the further development of sustainable light-harvesting applications.
Version 1 including Supplementary Information (SI)
download asset Blue_to-UV_upconversion_Pfund_et_al_V1.pdf 1 MB [opens in a new tab] cloud_download
pdf : 1 MB
download asset Blue_to-UV_upconversion_SI_Pfund_et_al_V1.pdf 3 MB [opens in a new tab] cloud_download
pdf : 3 MB
Blue to-UV upconversion SI Pfund et al V1