Dibenzothiophene Tetradentate Pt/Pd Complexes for Temperature Sensing
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Solution Overview
Problem
Existing platinum and palladium complexes with sulfur coordination bonds, primarily bidentate and tridentate, suffer from poor electrochemical and thermal stability and low phosphorescence efficiency, limiting their application beyond OLEDs.
Innovation Solution
Development of tetradentate platinum and palladium metal complexes based on dibenzothiophene coordination, featuring a 6/5/6 type tetradentate cyclometallated structure with Pt—S bonds, providing enhanced rigidity and temperature-responsive luminescence characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If bidentate and tridentate Pt(II) complexes with S coordination bonds are used, then the coordination bond strength is improved according to HSAB theory, but the electrochemical and thermal stability deteriorates and phosphorescence efficiency becomes low
Solution Approach 1:
The patent merges multiple coordination modes into a single tetradentate ligand structure that combines both S-coordination (for strong bonding per HSAB theory) and N-coordination (for planar rigidity). The ligand contains both dibenzothiophene S atoms and pyridine N atoms, creating a unified tetradentate coordination system that simultaneously achieves strong coordination bonds and high stability.
Solution Approach 2:
The patent creates a composite coordination environment by integrating S-donating dibenzothiophene units and N-donating pyridine units into a single tetradentate ligand framework. This composite ligand structure provides both the soft S-coordination needed for strong Pt/Pd bonding and the rigid planar N-coordination geometry needed for stability and high phosphorescence efficiency.
2Strength
If bidentate and tridentate Pt(II) complexes are used, then the coordination bond strength is improved, but the phosphorescence efficiency deteriorates
Solution Approach 1:
The patent merges multiple coordination modes into a single tetradentate ligand structure that combines both S-coordination (for strong bonding per HSAB theory) and N-coordination (for planar rigidity). The ligand contains both dibenzothiophene S atoms and pyridine N atoms, creating a unified tetradentate coordination system that simultaneously achieves strong coordination bonds and high stability.
Solution Approach 2:
The patent creates a composite coordination environment by integrating S-donating dibenzothiophene units and N-donating pyridine units into a single tetradentate ligand framework. This composite ligand structure provides both the soft S-coordination needed for strong Pt/Pd bonding and the rigid planar N-coordination geometry needed for stability and high phosphorescence efficiency.
3Use of energy by moving object
If tetradentate Pt(II) complexes with planar structure are used, then the quantum efficiency and molecular stability are improved, but the application scope in temperature response fields is limited
Solution Approach 1:
The patent changes the chemical composition parameters of the ligand by incorporating dibenzothiophene units with S atoms, which have different electronic properties compared to traditional N-donor ligands. This parameter change in ligand composition introduces temperature-responsive luminescence characteristics while maintaining the high quantum efficiency benefits of tetradentate planar structures, thereby expanding application scope to include optical thermometry.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The complexes exhibit significant temperature-dependent luminescence changes, allowing temperature estimation by naked eye and expanding applications to optical thermometers and other temperature-responsive fields.
Implementation Method 1
tetradentate Pt (II) complexes have attracted considerable attention due to the strong spin-orbit coupling of Pt atoms
Implementation Method 2
The provided materials have temperature response characteristics, and the corresponding relationship between temperature and fluorescence intensity can be obtained
Data Source
AI summary
The present invention provides a bivalent platinum or palladium metal complex phosphorescent material based on dibenzothiophene coordination and the use thereof. Wherein the phosphorescent material has the general structure shown in Formula (I):The complexes of the present invention are based on novel tetradentate ligands of 4-phenyldibenzothiophene and pyridoxyl anions and derivatives thereof, which are coordinated with central metal ions to form 6/5/6 type tetradentate cyclometallated complex phosphorescent materials, and the presence of Pt—S coordination bonds makes such materials have significant temperature response characteristics. The luminescence intensity increases with the decrease of temperature, and the emission wavelength blue-shifted with the decrease of temperature. The blue-green luminescence was observed at 77 K, but the yellow luminescence was observed at 289 K, which indicated the potential application in optical thermometers.