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Triangular platinum(II) metallacycles: syntheses, photophysics, and nonlinear optics
1Beijing National Laboratory for Molecular Sciences, Department of Applied Chemistry, Center for Soft Matter Science and Engineering, the Key Laboratory of Polymer Chemistry and Physics of the Ministry of Education, College of Chemistry, Peking University, Beijing 100871, China.
ACS Applied Materials & Interfaces
|March 5, 2015
Summary
Novel platinum(II) metallacycles with oligo(phenylene-ethynylene) ligands exhibit tunable photophysical properties. These complexes display significant two-photon absorption and reverse saturable absorption, making them promising for advanced optical applications.
Area of Science:
- Coordination Chemistry
- Photophysics
- Materials Science
Background:
- Metallacycles offer tunable electronic and photophysical properties.
- Oligo(phenylene-ethynylene) (OPE) ligands are known for their unique electronic characteristics and extended conjugation.
Purpose of the Study:
- To synthesize and characterize novel triangular platinum(II) diimine metallacycles with cyclic OPE bisacetylide ligands.
- To investigate the photophysical properties, including excited state behavior and two-photon absorption (2PA) capabilities.
- To explore the potential of these metallacycles in optical applications, such as two-photon excitation phosphorescence and reverse saturable absorption.
Main Methods:
- Synthesis of three triangular platinum(II) diimine metallacycles.
- Spectroscopic studies to analyze photophysical properties.
- Solvatochromic studies to understand excited state behavior in different solvents.
- Density functional theory (DFT) and time-dependent density functional theory (TD-DFT) calculations for theoretical validation.
Main Results:
- The synthesized metallacycles exhibit two distinct types of triplet excited states: ligand/metal-to-ligand charge-transfer and acetylide-ligand-centered.
- The lowest triplet state can switch between these two types in varied solvents due to energy level inversion influenced by solvent polarity.
- The complexes demonstrate significant two-photon absorption (2PA) cross-sections, reaching up to 1020 GM at 680 nm and 670 GM at 1040 nm.
- Pronounced reverse saturable absorption (RSA) was observed, attributed to strong transient triplet-state absorption.
Conclusions:
- The photophysical properties of platinum(II) metallacycles are strongly dependent on the size and electronic features of the cyclic OPE ligands.
- Solvent polarity plays a crucial role in tuning the excited state characteristics of these complexes.
- The demonstrated 2PA and RSA properties highlight the potential of these metallacycles for applications in nonlinear optics and optical limiting.
Keywords:
nonlinear opticsplatinum metallacycleplatinum(II) acetylidereverse saturable absorptiontwo-photon absorptionMore Related Videos
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