10.1021/acs.inorgchem.7b00961.s001
Guijie Li
Guijie
Li
Alicia Wolfe
Alicia
Wolfe
Jason Brooks
Jason
Brooks
Zhi-Qiang Zhu
Zhi-Qiang
Zhu
Jian Li
Jian
Li
Modifying Emission Spectral Bandwidth of Phosphorescent
Platinum(II) Complexes Through Synthetic Control
American Chemical Society
2017
substituent
PMMA
Pt
solution
electron-accepting pyridyl moiety
T 1 state properties
Modifying Emission Spectral Bandwidth
photophysical properties
tetradentate cyclometalating ligand
pyridyl ring
MLCT
film
platinum complexes
electron-accepting pyridyl group
2017-06-26 11:48:42
Journal contribution
https://acs.figshare.com/articles/journal_contribution/Modifying_Emission_Spectral_Bandwidth_of_Phosphorescent_Platinum_II_Complexes_Through_Synthetic_Control/5144002
The design, synthesis,
and characterization of a series of tetradentate
cyclometalated Pt(II) complexes are reported. The platinum complexes
have the general structure Pt(<i>ppz</i>-O-CbPy-R), where
a tetradentate cyclometalating ligand is consisting of <i>ppz</i> (3,5-dimethyl-1-phenyl-pyrazole), CbPy (carbazolylpyridine) components,
and an oxygen bridging group. Variations of the R group on the pyridyl
ring with various electron withdrawing and donating substituents are
shown to have profound effects on the photophysical properties of
Pt complexes. Electrochemical analysis indicates that reduction process
occurs mainly on the electron-accepting pyridyl group, and the irreversible
oxidation process is primarily localized on the metal-phenyl portions.
The studies of their photophysical properties indicate that the lowest
excited state of the platinum complexes is a ligand-centered <sup>3</sup>π–π* state with minor to significant <sup>1</sup>MLCT/<sup>3</sup>MLCT character and are strongly dependent
on the nature of the electron-accepting pyridyl moiety. A systematic
study of the substituent effects on the pyridyl ring demonstrates
that the T<sub>1</sub> state properties can be tuned by altering the
functionality and positions of substituents. Importantly, it is revealed
that how the emission spectra of the Pt(II) complexes can be significantly
narrowed and why it can be achieved by incorporating an electron-donating
group on the 4-position of the pyridyl ring. Most of the Pt(II) complexes
reported here are highly emissive at room temperature in dichloromethane
solutions (Φ = 1.1–95%) and in doped PMMA films (Φ
= 29–88%) with luminescent lifetimes in the microsecond range
(τ = 0.6–13.5 μs in solution and 0.9–11.3
μs in thin film respectively) and λ<sub>max</sub> = 442–568
nm and 440–544 nm in solution and thin film, respectively.
Moreover, these complexes are neutral and thermally stable for sublimation,
indicating that they can be useful for display and solid-state lighting
applications.