Efficient synthesis of carbazolyl- and thienyl-substituted beta-diketonates and properties of their red- and green-light-emitting Ir(III) complexes.
The efficient synthesis of novel beta-diketonates equipped with functional carbazolyl moieties and their subsequent transformations in 5-hexyl-thienyl substituted carbazole derivatives is presented by utilizing an effective Stille cross-coupling reaction. The introduced beta-diketonates served as ancillary ligands for novel heteroleptic red- and green-emitting Ir(III) complexes, when combined with 2-(naphthalen-1-yl)pyridine and 2-phenylpyridine as cyclometalating ligands. These novel Ir(III) complexes revealed color-tunability and a very good thermal stability until at least 207 degrees C. In polystyrene blends, the heteroleptic Ir(III) complexes revealed remarkable quantum yields up to 36% and suitably short phosphorescence lifetimes ranging from 1 to 4 micros. In the case of the orange-red Ir(III) emitter, equipped with 2-(naphthalen-1-yl)pyridine cyclometallating ligands, a luminous efficiency as high as 7.7 cd/A at 7.4 V was achieved. All fabricated diodes exhibited in addition favorable color stability.
Tian
Nan
N
Functional Polymers Group and Institute of Polymer Technology, University of Wuppertal, Gaussstrasse 20, D-42097 Wuppertal, Germany.
Thiessen
Alexander
A
Schiewek
Ralf
R
Schmitz
Oliver J
OJ
Hertel
Dirk
D
Meerholz
Klaus
K
Holder
Elisabeth
E