Article: Luminescent organoplatinum(II) complexes with functionalized cyclometalated C^N^C Ligands: Structures, Photophysical Properties, and Material Applications

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TitleLuminescent organoplatinum(II) complexes with functionalized cyclometalated C^N^C Ligands: Structures, Photophysical Properties, and Material Applications
AuthorsKui, SCF1
Hung, FF1
Lai, SL1
Yuen, MY1
Kwok, CC1
Low, KH1
Chui, SSY1
Che, CM1
Keywordscyclometalation
luminescence
metallacycles
platinum
tridentate ligands
Issue Date2012
PublisherWiley - V C H Verlag GmbH & Co KGaA. The Journal's web site is located at http://www.wiley-vch.de/home/chemistry
CitationChemistry - A European Journal, 2012, v. 18 n. 1, p. 96-109 [How to Cite?]
DOI: http://dx.doi.org/10.1002/chem.201101880
AbstractA series of [(R'-C^N^C-R')Pt(L)] complexes with doubly deprotonated cyclometalated R'-C^N^C-R' ligands (R'-C^N^C-R'=2,6-diphenylpyridine derivatives) functionalized with carbazole, fluorene, or thiophene unit(s) have been synthesized and their photophysical properties studied. The X-ray crystal structures reveal extensive intermolecular π̄π and C-H̄π interactions between the cyclometalated C^N^C ligands. Compared to previously reported cyclometalated platinum(II) complexes [(C^N^C)Pt(L)], which are non-emissive in solution at room temperature, the carbazole-, fluorene-and thiophene-functionalized [(R'-C^N^C-R')Pt(L)] (L=DMSO 1-9, C=N-Ar, 1a-9a) complexes are emissive in solution at room temperature with λ max at 564-619nm and ∥=0.02-0.26. The emissions of the [(R'-C^N^C-R')Pt(L)] complexes are attributed to electronic excited states with mixed 3MLCT and 3IL character. The carbazole/fluorene/ thiophene unit(s) allow the tuning of the electronic properties of the [(R'-C^N^C-R')Pt] moiety, with the emission maxima in a range of 564-619nm. These are the first examples of organoplatinum(II) complexes bearing doubly deprotonated cyclometalated C^N^C ligands that are emissive in solution at room temperature. In non-degassed DMSO, the emission intensities of 6a-9a are enhanced upon exposure to ambient light. This phenomenon is caused by reacting photogenerated 1O 2 with a DMSO molecule to form dimethyl sulfone, leading to the removal of dissolved oxygen in solution. Self-assembled nanowires and nanorods are obtained from precipitation of 3a in THF/H 2O and 8a in DMSO/Et 2O, respectively. The [(R'-C^N^C-R')Pt(L)] complexes are soluble in common organic solvents with a high thermal stability (>300°C), rendering them as phosphorescent dopants for organic light-emitting diode (OLEDs) applications. Red OLEDs with CIE coordinates of (0.65 ±0.01, 0.35 ±0.01) were fabricated from 7a or 8a. A maximum external efficiency (η Ext) of 12.6% was obtained for the device using 8a as emitter. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
ISSN0947-6539
2011 Impact Factor: 5.925
2011 SCImago Journal Rankings: 0.455
DOIhttp://dx.doi.org/10.1002/chem.201101880
ReferencesReferences in Scopus
GrantsResearch and development of phosphorescent organic light emitting diode (OLED) materials and prototype devices for lighting applications
Institute of Molecular Functional Materials
Self-assembled metal coordination polymers and supramolecular systems containing π-conjugated organic ligands
DC Field
Value
dc.contributor.authorKui, SCF
dc.contributor.authorHung, FF
dc.contributor.authorLai, SL
dc.contributor.authorYuen, MY
dc.contributor.authorKwok, CC
dc.contributor.authorLow, KH
dc.contributor.authorChui, SSY
dc.contributor.authorChe, CM
dc.date.accessioned2012-07-16T09:44:49Z
dc.date.available2012-07-16T09:44:49Z
dc.date.issued2012
dc.description.abstractA series of [(R'-C^N^C-R')Pt(L)] complexes with doubly deprotonated cyclometalated R'-C^N^C-R' ligands (R'-C^N^C-R'=2,6-diphenylpyridine derivatives) functionalized with carbazole, fluorene, or thiophene unit(s) have been synthesized and their photophysical properties studied. The X-ray crystal structures reveal extensive intermolecular π̄π and C-H̄π interactions between the cyclometalated C^N^C ligands. Compared to previously reported cyclometalated platinum(II) complexes [(C^N^C)Pt(L)], which are non-emissive in solution at room temperature, the carbazole-, fluorene-and thiophene-functionalized [(R'-C^N^C-R')Pt(L)] (L=DMSO 1-9, C=N-Ar, 1a-9a) complexes are emissive in solution at room temperature with λ max at 564-619nm and ∥=0.02-0.26. The emissions of the [(R'-C^N^C-R')Pt(L)] complexes are attributed to electronic excited states with mixed 3MLCT and 3IL character. The carbazole/fluorene/ thiophene unit(s) allow the tuning of the electronic properties of the [(R'-C^N^C-R')Pt] moiety, with the emission maxima in a range of 564-619nm. These are the first examples of organoplatinum(II) complexes bearing doubly deprotonated cyclometalated C^N^C ligands that are emissive in solution at room temperature. In non-degassed DMSO, the emission intensities of 6a-9a are enhanced upon exposure to ambient light. This phenomenon is caused by reacting photogenerated 1O 2 with a DMSO molecule to form dimethyl sulfone, leading to the removal of dissolved oxygen in solution. Self-assembled nanowires and nanorods are obtained from precipitation of 3a in THF/H 2O and 8a in DMSO/Et 2O, respectively. The [(R'-C^N^C-R')Pt(L)] complexes are soluble in common organic solvents with a high thermal stability (>300°C), rendering them as phosphorescent dopants for organic light-emitting diode (OLEDs) applications. Red OLEDs with CIE coordinates of (0.65 ±0.01, 0.35 ±0.01) were fabricated from 7a or 8a. A maximum external efficiency (η Ext) of 12.6% was obtained for the device using 8a as emitter. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
dc.description.grantResearch and development of phosphorescent organic light emitting diode (OLED) materials and prototype devices for lighting applications
dc.description.grantInstitute of Molecular Functional Materials
dc.description.grantSelf-assembled metal coordination polymers and supramolecular systems containing π-conjugated organic ligands
dc.description.grantcode104987
dc.description.grantcode101180
dc.description.grantcode99415
dc.description.naturelink_to_OA_fulltext
dc.identifier.citationChemistry - A European Journal, 2012, v. 18 n. 1, p. 96-109 [How to Cite?]
DOI: http://dx.doi.org/10.1002/chem.201101880
dc.identifier.doihttp://dx.doi.org/10.1002/chem.201101880
dc.identifier.epage109
dc.identifier.hkuros209974
dc.identifier.hkuros205180
dc.identifier.isiWOS:000298547800014
Funding AgencyGrant Number
Innovation and Technology Commission of the HKSAR GovernmentITF/016/08NP
GHP/043/10
University Grants Committee of the Hong Kong SARAoE/P-03/08
Research Grants Council of Hong Kong SARHKU 7008/09P
National Natural Science Foundation of China/Research Grants CouncilN_HKU 752/08
Chinese Academy of Sciences-Croucher Foundation
Guangdong Special Project of the Introduction of Innovative RD Teams, China
Funding Information:

We acknowledge support from the Innovation and Technology Commission of the HKSAR Government (ITF/016/08NP and GHP/043/10), the University Grants Committee of the Hong Kong SAR (AoE/P-03/08), Research Grants Council of Hong Kong SAR (HKU 7008/09P), National Natural Science Foundation of China/Research Grants Council Joint Research Scheme [N_HKU 752/08] and The Chinese Academy of Sciences-Croucher Foundation Funding Scheme For Joint Laboratories. This work was also supported by Guangdong Special Project of the Introduction of Innovative R&D Teams, China.

dc.identifier.issn0947-6539
2011 Impact Factor: 5.925
2011 SCImago Journal Rankings: 0.455
dc.identifier.issue1
dc.identifier.scopuseid_2-s2.0-84555190151
dc.identifier.spage96
dc.identifier.urihttp://hdl.handle.net/10722/152642
dc.identifier.volume18
dc.languageeng
dc.publisherWiley - V C H Verlag GmbH & Co KGaA. The Journal's web site is located at http://www.wiley-vch.de/home/chemistry
dc.publisher.placeGermany
dc.relation.ispartofChemistry - A European Journal
dc.relation.referencesReferences in Scopus
dc.subjectcyclometalation
dc.subjectluminescence
dc.subjectmetallacycles
dc.subjectplatinum
dc.subjecttridentate ligands
dc.titleLuminescent organoplatinum(II) complexes with functionalized cyclometalated C^N^C Ligands: Structures, Photophysical Properties, and Material Applications
dc.typeArticle
Author Affiliations
  1. The University of Hong Kong