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Visible Light‐Gated Organocatalysis Using a Ru II ‐Photocage
Author(s) -
GonzálezDelgado José A.,
Romero Miguel A.,
Boscá Francisco,
Arteaga Jesús F.,
Pischel Uwe
Publication year - 2020
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.202001893
Subject(s) - chemistry , organocatalysis , photochemistry , catalysis , acetic anhydride , spectroscopy , irradiation , absorption (acoustics) , visible spectrum , organic chemistry , materials science , physics , quantum mechanics , nuclear physics , composite material , enantioselective synthesis , optoelectronics
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.