Chen, Hsiao-Fan Hung, Wen-Yi Chen, Shou-Wei Wang, Ting-Chih Lin, Shih-Wei Chou, Shu-Hua Liao, Chih-Teng Su, Hai-Ching Pan, Hsiao-An Chou, Pi-Tai Liu, Yi-Hung Wong, Ken-Tsung Cationic Iridium Complexes with Intramolecular π–π Interaction and Enhanced Steric Hindrance for Solid-State Light-Emitting Electrochemical Cells Cationic iridium complexes incorporated 4,5-diaza-9,9′-spirobifluorene as N<sup>∧</sup>N ancillary ligands, in which one (<b>2</b>) or two (<b>3</b>) phenyl groups were introduced onto 4,5-diazafluorene to afford intraligand π–π interactions. The X-ray crystal structures of complexes <b>2</b> and <b>3</b> show that the pendant phenyl ring forms strong intramolecular face-to-face π-stacking with the difluorophenyl ring of the cyclometalated ligand with distances of 3.38 Å for complex <b>2</b> and 3.40 and 3.46 Å for complex <b>3</b>. This π–π stacking interaction minimizes the expansion of the metal–ligand bonds in the excited state, resulting in a longer device lifetime in the light-emitting electrochemical cell (LEC) devices. intraligand;device lifetime;cyclometalated ligand;electrochemical;intramolecular;Enhanced Steric Hindrance;3.40;difluorophenyl ring;LEC;CellsCationic;Intramolecular;complexes 2;3.46 Å;Interaction;3 show;interaction;diazafluorene;Cationic Iridium Complexes;pendant phenyl ring forms;crystal;iridium;Electrochemical;diaza;3.38 Å;bond 2012-11-19
    https://acs.figshare.com/articles/dataset/Cationic_Iridium_Complexes_with_Intramolecular__Interaction_and_Enhanced_Steric_Hindrance_for_Solid_State_Light_Emitting_Electrochemical_Cells/2467603
10.1021/ic300673k.s002