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N, N ‐heterocyclic Ancillary Ligands for Enhanced Photoluminescence Quantum Yields of Orange/Red‐Emitting 1‐(4‐(Trifluoromethyl)phenyl)isoquinoline‐Based Iridium (III) Complexes
Author(s) -
Yang XiaoHan,
Dou ShaoBin,
Zhang Qian,
Yang RuiLian,
Liu Zhuo,
Li GaoNan,
Niu ZhiGang
Publication year - 2021
Publication title -
zeitschrift für anorganische und allgemeine chemie
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.354
H-Index - 66
eISSN - 1521-3749
pISSN - 0044-2313
DOI - 10.1002/zaac.202000298
Subject(s) - chemistry , iridium , photoluminescence , pyrazine , excited state , isoquinoline , trifluoromethyl , pyridine , intermolecular force , hydrogen bond , crystallography , phosphorescence , photochemistry , medicinal chemistry , stereochemistry , fluorescence , molecule , catalysis , organic chemistry , materials science , alkyl , optoelectronics , physics , quantum mechanics , nuclear physics
Four new cationic iridium (III) complexes: [(cf 3 piq) 2 Ir(pzpy)] + PF 6 − ( Ir1 ), [(cf 3 piq) 2 Ir(pzpyz)] + PF 6 − ( Ir2 ), [(cf 3 piq) 2 Ir(impy)] + PF 6 − ( Ir3 ), and [(cf 3 piq) 2 Ir(impyz)] + PF 6 − ( Ir4 ) (where cf 3 piq=1‐(4‐(trifluoromethyl)phenyl)isoquinoline, pzpy=2‐(1H‐pyrazol‐3‐yl)pyridine, pzpyz=2‐(1H‐pyrazol‐3‐yl)pyrazine, impy=2‐(1H‐imidazol‐2‐yl)pyridine, and impyz=2‐(1H‐imidazol‐2‐yl)pyrazine) have been synthesized and fully characterized. The single crystal structure of Ir3 has been determined by X‐ray diffraction, and confirmed to have two hydrogen bonds (C14−H14⋅⋅⋅N2 and C57−H57⋅⋅⋅N9) and one intermolecular π‐π stacking interaction. The UV‐vis absorption, photoluminescence, and electrochemistry properties of all complexes have been studied. These complexes emit orange‐red photoluminescence with quantum yields of 28–46 % and excited state lifetimes of 0.48‐0.65 μs in CH 2 Cl 2 solution at room temperature. Based on the DFT calculations, we concluded that their emission originated predominantly from a hybrid 3 MLCT/ 3 ILCT excited state.