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Title: Highly efficient phosphorescence from cyclometallated iridium(III) compounds: Improved syntheses of picolinate complexes and quantum chemical studies of their electronic structures

Abstract

In this work, we report a new method to make heteroleptic cyclometallated iridium(III) complexes that employs 1,2-dimethoxyethane (DME) instead of the commonly used 2-ethoxyethanol for the addition of ancillary ligands to chloro-bridged dimeric iridium species. Thus, picolinic acid was quickly and cleanly added to [(F 2ppy)2Ir(Cl)]2 (where F 2ppy=2-(4',6'-difluorophenyl)pyridinato) with base under DME reflux to afford (F 2ppy) 2Ir(picolinate) (FIrpic) in excellent yield. The high purity of the products obviates the need for further purification, an improvement over the common route in which column chromatography is required. We prepared eleven picolinate complexes by this route, eight of which were characterized by single crystal x-ray diffraction. The complexes possess the same distorted octahedral geometry with two bidentate phenylpyridine ligands and one bidentate 2-picolinate ligand. All of the compounds exhibited efficient phosphorescence with colors ranging from blue to orange; photophysical measurements revealed emission quantum yields as high as 0.92, while most surpassed 0.5. Time-dependent density functional theory calculations, coupled with the use of natural transition orbitals (NTOs), allowed a detailed interpretation of the electronic structures for the complexes. The nature of the acceptor orbital for the lowest-energy triplet state NTO was discovered to be an important predictor for the emission spectra ofmore » FIrpic and its congeners.« less

Authors:
 [1];  [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), Office of Defense Nuclear Nonproliferation (NA-20); USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22). Chemical Sciences, Geosciences & Biosciences Division
OSTI Identifier:
1580469
Alternate Identifier(s):
OSTI ID: 1576636
Report Number(s):
LLNL-JRNL-769051
Journal ID: ISSN 0020-1693; 960489
Grant/Contract Number:  
AC52-07NA27344; AC03-76SF00098; FG02-17ER16362
Resource Type:
Accepted Manuscript
Journal Name:
Inorganica Chimica Acta
Additional Journal Information:
Journal Volume: 496; Journal Issue: C; Journal ID: ISSN 0020-1693
Publisher:
Elsevier
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; Photoluminescencel Phosphorescent iridium complex; Blue emission; DFT calculations; OLED; FIrpic synthesis

Citation Formats

Sanner, Robert D., Cherepy, Nerine J., Martinez, H. Paul, Pham, Hung Q., and Young, Victor G. Highly efficient phosphorescence from cyclometallated iridium(III) compounds: Improved syntheses of picolinate complexes and quantum chemical studies of their electronic structures. United States: N. p., 2019. Web. doi:10.1016/j.ica.2019.119040.
Sanner, Robert D., Cherepy, Nerine J., Martinez, H. Paul, Pham, Hung Q., & Young, Victor G. Highly efficient phosphorescence from cyclometallated iridium(III) compounds: Improved syntheses of picolinate complexes and quantum chemical studies of their electronic structures. United States. doi:10.1016/j.ica.2019.119040.
Sanner, Robert D., Cherepy, Nerine J., Martinez, H. Paul, Pham, Hung Q., and Young, Victor G. Thu . "Highly efficient phosphorescence from cyclometallated iridium(III) compounds: Improved syntheses of picolinate complexes and quantum chemical studies of their electronic structures". United States. doi:10.1016/j.ica.2019.119040.
@article{osti_1580469,
title = {Highly efficient phosphorescence from cyclometallated iridium(III) compounds: Improved syntheses of picolinate complexes and quantum chemical studies of their electronic structures},
author = {Sanner, Robert D. and Cherepy, Nerine J. and Martinez, H. Paul and Pham, Hung Q. and Young, Victor G.},
abstractNote = {In this work, we report a new method to make heteroleptic cyclometallated iridium(III) complexes that employs 1,2-dimethoxyethane (DME) instead of the commonly used 2-ethoxyethanol for the addition of ancillary ligands to chloro-bridged dimeric iridium species. Thus, picolinic acid was quickly and cleanly added to [(F2ppy)2Ir(Cl)]2 (where F2ppy=2-(4',6'-difluorophenyl)pyridinato) with base under DME reflux to afford (F2ppy)2Ir(picolinate) (FIrpic) in excellent yield. The high purity of the products obviates the need for further purification, an improvement over the common route in which column chromatography is required. We prepared eleven picolinate complexes by this route, eight of which were characterized by single crystal x-ray diffraction. The complexes possess the same distorted octahedral geometry with two bidentate phenylpyridine ligands and one bidentate 2-picolinate ligand. All of the compounds exhibited efficient phosphorescence with colors ranging from blue to orange; photophysical measurements revealed emission quantum yields as high as 0.92, while most surpassed 0.5. Time-dependent density functional theory calculations, coupled with the use of natural transition orbitals (NTOs), allowed a detailed interpretation of the electronic structures for the complexes. The nature of the acceptor orbital for the lowest-energy triplet state NTO was discovered to be an important predictor for the emission spectra of FIrpic and its congeners.},
doi = {10.1016/j.ica.2019.119040},
journal = {Inorganica Chimica Acta},
number = C,
volume = 496,
place = {United States},
year = {2019},
month = {7}
}

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This content will become publicly available on July 25, 2020
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