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Controlling Lanthanide Exchange in Triple‐Stranded Helicates: A Way to Optimize Molecular Light‐Upconversion
Author(s) -
Zare Davood,
Suffren Yan,
Nozary Homayoun,
Hauser Andreas,
Piguet Claude
Publication year - 2017
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201709156
Subject(s) - lanthanide , chemistry , tripod (photography) , gallium , photon upconversion , lability , dodecahedron , scrambling , energy transfer , kinetic energy , luminescence , crystallography , chemical physics , materials science , optoelectronics , ion , organic chemistry , optics , physics , linguistics , philosophy , quantum mechanics
The kinetic lability of hexadentate gallium‐based tripods is sufficient to ensure thermodynamic self‐assembly of luminescent heterodimetallic [GaLn( L3 ) 3 ] 6+ helicates on the hour time scale, where Ln is a trivalent 4f‐block cation. The inertness is, however, large enough for preserving the triple‐helical structure when [GaLn( L3 ) 3 ] 6+ is exposed to lanthanide exchange. The connection of a second gallium‐based tripod further slows down the exchange processes to such an extent that spectroscopically active [CrErCr( L4 ) 3 ] 9+ can be diluted into closed‐shell [GaYGa( L4 ) 3 ] 9+ matrices without metal scrambling. This feature is exploited for pushing molecular‐based energy‐transfer upconversion (ETU) at room temperature.