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Title: Phosphorescent heteroleptic iridium(III) cyclometallates: Improved syntheses of acetylacetonate complexes and quantum chemical studies of their excited state properties

Abstract

We have investigated methods to prepare cyclometallated iridium(III) complexes with efficient photoluminescence spanning a broad color palette. In particular, we find that addition of ancillary ligands to chloro-bridged iridium dimers proceeds cleanly in refluxing 1,2-dimethoxyethane (DME) without the need for additional product purification. This represents an improvement over the conventional use of 2-ethoxyethanol which requires column chromatographic separation. Our efforts in this work have focused on acetylacetonate complexes such as (F 2ppy) 2Ir(acac), where F 2ppy = 2-(4',6'-diflurophenyl)pyridinato. We have prepared fifteen compounds by the route, eight of which are newly reported; in four cases we were able to prepare complexes which were inaccessible via the conventional route. Nine of the complexes were characterized by single crystal x-ray diffraction and possess the same distorted octahedral geometry around the iridium with two bidentate phenylpyridine ligands and one bidentate acetylacetonate ligand. Seven of the complexes exhibited efficient photoluminescence with colors ranging from yellow to blue and quantum yields of 0.51–0.74. All of the compounds with trifluoromethyl or phenyl substituents on the acetylacetone displayed emission in the orange with low quantum efficiency. The use of TD-DFT calculations, along with natural transition orbitals (NTOs), permitted a detailed interpretation of the electronic structures for themore » complexes. Here, the nature of the acceptor orbitals for the low energy triplet state NTOs proved to be an important predictor for the emission spectra of the compounds.« less

Authors:
ORCiD logo [1];  [1];  [2];  [2]
  1. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
  2. Univ. of Minnesota, Minneapolis, MN (United States)
Publication Date:
Research Org.:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Sponsoring Org.:
USDOE National Nuclear Security Administration (NNSA); USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22). Chemical Sciences, Geosciences & Biosciences Division
OSTI Identifier:
1583044
Report Number(s):
LLNL-JRNL-800583
Journal ID: ISSN 0277-5387; 1003765
Grant/Contract Number:  
AC52-07NA27344; AC03-76SF00098; CHEM5755; FG02-17ER16362
Resource Type:
Accepted Manuscript
Journal Name:
Polyhedron
Additional Journal Information:
Journal Volume: 176; Journal Issue: C; Journal ID: ISSN 0277-5387
Publisher:
Elsevier
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; Photoluminescence; Phosphorescent iridium complex; DFT calculations; OLED; Cyclometallated iridium synthesis

Citation Formats

Sanner, Robert D., Cherepy, Nerine J., Pham, Hung Q., and Young, Jr., Victor G. Phosphorescent heteroleptic iridium(III) cyclometallates: Improved syntheses of acetylacetonate complexes and quantum chemical studies of their excited state properties. United States: N. p., 2019. Web. doi:10.1016/j.poly.2019.114256.
Sanner, Robert D., Cherepy, Nerine J., Pham, Hung Q., & Young, Jr., Victor G. Phosphorescent heteroleptic iridium(III) cyclometallates: Improved syntheses of acetylacetonate complexes and quantum chemical studies of their excited state properties. United States. doi:10.1016/j.poly.2019.114256.
Sanner, Robert D., Cherepy, Nerine J., Pham, Hung Q., and Young, Jr., Victor G. Thu . "Phosphorescent heteroleptic iridium(III) cyclometallates: Improved syntheses of acetylacetonate complexes and quantum chemical studies of their excited state properties". United States. doi:10.1016/j.poly.2019.114256.
@article{osti_1583044,
title = {Phosphorescent heteroleptic iridium(III) cyclometallates: Improved syntheses of acetylacetonate complexes and quantum chemical studies of their excited state properties},
author = {Sanner, Robert D. and Cherepy, Nerine J. and Pham, Hung Q. and Young, Jr., Victor G.},
abstractNote = {We have investigated methods to prepare cyclometallated iridium(III) complexes with efficient photoluminescence spanning a broad color palette. In particular, we find that addition of ancillary ligands to chloro-bridged iridium dimers proceeds cleanly in refluxing 1,2-dimethoxyethane (DME) without the need for additional product purification. This represents an improvement over the conventional use of 2-ethoxyethanol which requires column chromatographic separation. Our efforts in this work have focused on acetylacetonate complexes such as (F2ppy)2Ir(acac), where F2ppy = 2-(4',6'-diflurophenyl)pyridinato. We have prepared fifteen compounds by the route, eight of which are newly reported; in four cases we were able to prepare complexes which were inaccessible via the conventional route. Nine of the complexes were characterized by single crystal x-ray diffraction and possess the same distorted octahedral geometry around the iridium with two bidentate phenylpyridine ligands and one bidentate acetylacetonate ligand. Seven of the complexes exhibited efficient photoluminescence with colors ranging from yellow to blue and quantum yields of 0.51–0.74. All of the compounds with trifluoromethyl or phenyl substituents on the acetylacetone displayed emission in the orange with low quantum efficiency. The use of TD-DFT calculations, along with natural transition orbitals (NTOs), permitted a detailed interpretation of the electronic structures for the complexes. Here, the nature of the acceptor orbitals for the low energy triplet state NTOs proved to be an important predictor for the emission spectra of the compounds.},
doi = {10.1016/j.poly.2019.114256},
journal = {Polyhedron},
number = C,
volume = 176,
place = {United States},
year = {2019},
month = {12}
}

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