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Visible Light-Gated Organocatalysis Using a RuII -Photocage.

José A González-DelgadoMiguel A RomeroFrancisco BoscáJesús F ArteagaUwe Pischel
Published in: Chemistry (Weinheim an der Bergstrasse, Germany) (2020)
The light-gated organocatalysis via the release of 4-N,N-dimethylaminopyridine (DMAP) by irradiation of the [Ru(bpy)2 (DMAP)2 ]2+ complex with visible light was investigated. As model reaction the acetylation of benzyl alcohols with acetic anhydride was chosen. The pre-catalyst releases one DMAP molecule on irradiation at wavelengths longer than 455 nm. The photochemical process was characterized by steady-state irradiation and ultrafast transient absorption spectroscopy. The latter enabled the observation of the 3 MLCT state and the spectral features of the penta-coordinated intermediate [Ru(bpy)2 (DMAP)]2+ . The released DMAP catalyzes the acetylation of a wide range of benzyl alcohols with chemical yields of up to 99 %. Control experiments revealed unequivocally that it is the released DMAP which takes the role of the catalyst.
Keyphrases
  • visible light
  • energy transfer
  • radiation induced
  • high resolution
  • single cell
  • ionic liquid
  • radiation therapy
  • atomic force microscopy
  • magnetic resonance
  • cerebral ischemia
  • blood brain barrier
  • quantum dots