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Tuning the Decay Time of Lanthanide‐Based Near Infrared Luminescence from Micro‐ to Milliseconds through d→f Energy Transfer in Discrete Heterobimetallic Complexes
Author(s) -
Torelli Stéphane,
Imbert Daniel,
Cantuel Martine,
Bernardinelli Gérald,
Delahaye Sandra,
Hauser Andreas,
Bünzli JeanClaude G.,
Piguet Claude
Publication year - 2005
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.200401158
Subject(s) - lanthanide , luminescence , chromophore , intermetallic , kinetic energy , materials science , stokes shift , infrared , crystallography , chemistry , ion , photochemistry , physics , optoelectronics , optics , organic chemistry , alloy , quantum mechanics , composite material
Inert and optically active pseudo‐octahedral Cr III N 6 and Ru II N 6 chromophores have been incorporated by self‐assembly into heterobimetallic triple‐stranded helicates HHH ‐[CrLnL 3 ] 6+ and HHH ‐[RuLnL 3 ] 5+ . The crystal structures of [CrLnL 3 ](CF 3 SO 3 ) 6 (Ln=Nd, Eu, Yb, Lu) and [RuLnL 3 ](CF 3 SO 3 ) 5 (Ln=Eu, Lu) demonstrate that the helical structure can accommodate metal ions of different sizes, without sizeable change in the intermetallic M⋅⋅⋅Ln distances. These systems are ideally suited for unravelling the molecular factors affecting the intermetallic n d→4f communication. Visible irradiation of the Cr III N 6 and Ru II N 6 chromophores in HHH ‐[MLnL 3 ] 5/6+ (Ln=Nd, Yb, Er; M=Cr, Ru) eventually produces lanthanide‐based near infrared (NIR) emission, after directional energy migration within the complexes. Depending on the kinetic regime associated with each specific d–f pair, the NIR luminescence decay times can be tuned from micro‐ to milliseconds. The origin of this effect, together with its rational control for programming optical functions in discrete heterobimetallic entities, are discussed.