TY - JOUR

T1 - Red-to-NIR Iridium(III) Emitters

T2 - Synthesis, Photophysical and Computational Study, the Effects of Cyclometallating and beta-Diketonate Ligands

AU - Kuznetsov, Kirill M.

AU - Kritchenkov, Ilya S.

AU - Shakirova, Julia R.

AU - Gurzhiy, Vladislav V.

AU - Pavlovskiy, Vladimir V.

AU - Porsev, Vitaly V.

AU - Sokolov, Viktor V.

AU - Tunik, Sergey P.

N1 - Publisher Copyright: © 2021 Wiley-VCH GmbH

PY - 2021/6/14

Y1 - 2021/6/14

N2 - In this work nine novel heteroleptic Ir(III) complexes of general formulae [Ir((Formula presented.) #)2((Formula presented.) #)] containing four different cyclometallating and four β-diketonate ligands were synthesized and fully characterized. Six of them display phosphorescence in the deep red and NIR regions with quantum yields reaching 24.6 % in degassed solution for one of the NIR emitters. Variation in the nature of orthometalating ligands results in dramatic changes in photophysical behavior: the compounds containing 2-phenylpyridine ((Formula presented.) 1) and 2-(benzo[b]thiophen-2-yl)pyridine ((Formula presented.) 2) ligands give non-emissive complexes, whereas those with methyl 2-phenylquinoline-4-carboxylate ((Formula presented.) 3) and 6-(benzo[b]thiophen-2-yl)phenanthridine) ((Formula presented.) 4) are luminescent, but display different character of electronic transitions responsible for absorption and emission. Complexes with the (Formula presented.) 3 ligand luminesce from 3LC excited state and do not change their emission characteristics upon variations in the nature of β-diketonates. On the contrary, the compounds based on the (Formula presented.) 4 cyclometalating ligand emit from the excited state with considerable contribution of 3MLCT character and show systematic bathochromic shift of absorption and emission bands upon increase in electron donicity of (Formula presented.) # ligands. This conclusion was supported by DFT and TD-DFT calculations and by the analysis of correlations between the 13C chemical shift of the diketonate C(H) carbon and emission maxima of the compounds under study.

AB - In this work nine novel heteroleptic Ir(III) complexes of general formulae [Ir((Formula presented.) #)2((Formula presented.) #)] containing four different cyclometallating and four β-diketonate ligands were synthesized and fully characterized. Six of them display phosphorescence in the deep red and NIR regions with quantum yields reaching 24.6 % in degassed solution for one of the NIR emitters. Variation in the nature of orthometalating ligands results in dramatic changes in photophysical behavior: the compounds containing 2-phenylpyridine ((Formula presented.) 1) and 2-(benzo[b]thiophen-2-yl)pyridine ((Formula presented.) 2) ligands give non-emissive complexes, whereas those with methyl 2-phenylquinoline-4-carboxylate ((Formula presented.) 3) and 6-(benzo[b]thiophen-2-yl)phenanthridine) ((Formula presented.) 4) are luminescent, but display different character of electronic transitions responsible for absorption and emission. Complexes with the (Formula presented.) 3 ligand luminesce from 3LC excited state and do not change their emission characteristics upon variations in the nature of β-diketonates. On the contrary, the compounds based on the (Formula presented.) 4 cyclometalating ligand emit from the excited state with considerable contribution of 3MLCT character and show systematic bathochromic shift of absorption and emission bands upon increase in electron donicity of (Formula presented.) # ligands. This conclusion was supported by DFT and TD-DFT calculations and by the analysis of correlations between the 13C chemical shift of the diketonate C(H) carbon and emission maxima of the compounds under study.

KW - Cyclometalated ligands

KW - Diketonate ligands

KW - Iridium

KW - Ligand impact

KW - Phosphorescence

KW - IR(III) COMPLEXES

KW - PROPERTY

KW - EXCITED-STATES

KW - MOLECULAR DESIGN

KW - VISIBLE-LIGHT

KW - PHOSPHORESCENT

KW - LUMINESCENCE

KW - LIGHT-EMITTING DEVICES

UR - http://www.scopus.com/inward/record.url?scp=85106040364&partnerID=8YFLogxK

UR - https://www.mendeley.com/catalogue/c59db82b-4c48-3633-b83e-60e57dd3fd05/

U2 - 10.1002/ejic.202100189

DO - 10.1002/ejic.202100189

M3 - Article

AN - SCOPUS:85106040364

VL - 2021

SP - 2163

EP - 2170

JO - Berichte der deutschen chemischen Gesellschaft

JF - Berichte der deutschen chemischen Gesellschaft

SN - 0365-9496

IS - 22

ER -