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Rational Color Tuning and Luminescent Properties of Functionalized Boron‐Containing 2‐Pyridyl Pyrrolide Complexes
Author(s) -
Chen H.Y.,
Chi Y.,
Liu C.S.,
Yu J.K.,
Cheng Y.M.,
Chen K.S.,
Chou P.T.,
Peng S.M.,
Lee G.H.,
Carty A. J.,
Yeh S.J.,
Chen C.T.
Publication year - 2005
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.200400250
Subject(s) - materials science , reagent , electroluminescence , photoluminescence , quantum yield , time dependent density functional theory , density functional theory , chelation , photochemistry , analytical chemistry (journal) , chemistry , nanotechnology , optoelectronics , fluorescence , computational chemistry , organic chemistry , optics , layer (electronics) , physics , metallurgy
Three systematically functionalized pyrrolide ligands were prepared via the coupling of methyl vinyl ketone and the respective carbaldehyde reagents, followed by treatment of the pre‐formed dicarbonyl compounds with (NH 4 ) 2 CO 3 in order to generate the required pyrrole fragment. These ligands readily reacted with the boron reagent BPh 3 to afford the complexes [(pyro)BPh 2 ] ( 2a ), [(noro)BPh 2 ] ( 2b ), and [(xaro)BPh 2 ] ( 2c ), where (pyro)H, (noro)H, and (xaro)H represents the 2‐pyridyl, 2‐quinolinyl, and 2‐quinoxalinyl pyrrole groups, respectively. Complexes 2a – 2c give stable solutions in air, and show strong photoluminescence with emission peak maxima located at 490 nm, 510 nm, and 575 nm, respectively. Calculations based upon time‐dependent density function theory (TDDFT) show that the S 1 state in these complexes is attributed to an allowed (π‐symmetry) → π* (π‐symmetry) transition located at the chelating pyrrolide moieties. Electroluminescence (EL) devices based on 2c were fabricated. The EL emission from 2c as the host‐emitter, with the emission peak maximum shifted to 580 nm, was observed when BCP was used as the hole blocking material. This device produces saturated red‐orange light‐emission at an onset voltage of 8 V and a maximum brightness of 5000 cd m –2 at a driving voltage of 15 V; the external quantum yield is estimated to be 0.5 %.