Luminescent Pt( ii ) complexes featuring imidazolylidene–pyridylidene and dianionic bipyrazolate: from fundamentals to OLED fabrications
Pt( ii ) complexes bearing imidazolylidene–pyridylidene (impy) and dianionic biazolate chelates were synthesized, for which the end products depend on the alkyl substituents of the impy chelate. Treatment of Pt(DMSO) 2 Cl 2 with dimethyl substituted imidazolium–pyridinium pro-ligand Me 2 impy(PF 6 )...
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Published in | Journal of materials chemistry. C, Materials for optical and electronic devices Vol. 5; no. 6; pp. 1420 - 1435 |
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Main Authors | , , , , , , , , , |
Format | Journal Article |
Language | English |
Published |
2017
|
Subjects | |
Online Access | Get full text |
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Summary: | Pt(
ii
) complexes bearing imidazolylidene–pyridylidene (impy) and dianionic biazolate chelates were synthesized, for which the end products depend on the alkyl substituents of the impy chelate. Treatment of Pt(DMSO)
2
Cl
2
with dimethyl substituted imidazolium–pyridinium pro-ligand Me
2
impy(PF
6
)
2
, followed by addition of 5,5′-(1-methylethylidene)-bis-(3-trifluoromethyl-1
H
-pyrazole) (mepzH
2
), 5,5′-di(trifluoromethyl)-3,3′-bis-pyrazole (bipzH
2
), and 5,5′-di(pentafluoroethyl)-3,3′-bis-pyrazole (biepzH
2
), afforded Pt(
ii
) complexes [Pt(Me
2
impy)(mepz)] (
1
), [Pt(Me
2
impy)(bipz)] (
2
) and [Pt(Me
2
impy)(biepz)] (
3
), respectively. In contrast, reactions with ethyl and isopropyl substituted Et
2
impy(PF
6
)
2
and Pr
2
impy(PF
6
)
2
and with bipzH
2
gave [Pt(EtimHpy)(bipz)] (
4
) and [Pt(PrimHpy)(bipz)] (
5
) respectively, where notable alkyl-to-hydrogen transformations on the pyridylidene fragment took place. The reaction of Pt(DMSO)
2
Cl
2
with Et
2
impy(PF
6
)
2
followed by addition of (biepzH
2
) gave two products [Pt(Et
2
impy)(biepz)] (
6
) and [Pt(EtimHpy)(biepz)] (
7
). Single crystal X-ray diffraction analyses of
1
,
2
and
5
revealed negligible intermolecular Pt⋯Pt interactions. Hybrid-DFT and TD-DFT computations were carried out on
1
,
2
and
5
to model the observed crystal structures and explain the photophysical data successfully. Organic light emitting diodes (OLEDs) were fabricated from complexes
4
or
5
using a multiple layered device architecture. The associated OLED performances (
i.e. η
max
= 12.5%, 11.2%,
η
L
= 44.0 cd A
−1
, 40.6 cd A
−1
, and
η
P
= 28.0 lm W
−1
, 25.8 lm W
−1
for
4
and
5
) confirmed their suitability in serving as potential OLED phosphors. |
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Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 2050-7526 2050-7534 |
DOI: | 10.1039/C6TC05154E |