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Octahedral molybdenum cluster complexes with aromatic sulfonate ligands
Olga A Efremova1, Yuri A Vorotnikov, Konstantin A Brylev
1Department of Chemistry, University of Hull, Cottingham Road, Hull, HU6 7RX, UK. o.efremova@hull.ac.uk.
Dalton Transactions (Cambridge, England : 2003)
|September 9, 2016
Summary
New molybdenum clusters with aromatic sulfonate ligands exhibit red photoluminescence and singlet oxygen generation. Complexes with iodide ({Mo6I8}4+) cores show the highest quantum yields and enhanced electrochemical stability.
Area of Science:
- Inorganic Chemistry
- Materials Science
- Photochemistry
Background:
- Molybdenum-based metal clusters are known for their unique electronic and photophysical properties.
- Aromatic sulfonate ligands offer tunable steric and electronic characteristics for metal cluster complexes.
- Understanding the structure-property relationships of these complexes is crucial for developing new functional materials.
Purpose of the Study:
- To synthesize and characterize novel octahedral molybdenum cluster complexes with aromatic sulfonate ligands.
- To investigate the spectroscopic (photoluminescence) and redox properties of these new complexes.
- To evaluate the impact of ligand choice and cluster core composition on their photophysical and electrochemical behavior.
Main Methods:
- Synthesis of tetrabutylammonium salts of octahedral molybdenum clusters with p-toluenesulfonate (OTs-) and benzenesulfonate (PhSO3-) ligands.
- Structural characterization of the synthesized complexes.
- Photoluminescence spectroscopy to determine emission wavelengths and quantum yields.
- Cyclic voltammetry to assess electrochemical properties and stability.
Main Results:
- Successful synthesis of (nBu4N)2[{Mo6X8}(OTs)6] and (nBu4N)2[{Mo6X8}(PhSO3)6] complexes (X = Cl, Br, I).
- All synthesized complexes displayed red photoluminescence and generated singlet oxygen.
- Complexes featuring the {Mo6I8}4+ core exhibited the highest photoluminescence quantum yields (>0.6) and narrowest emission bands.
- The new sulfonate-ligated complexes demonstrated enhanced stability towards electrochemical oxidation compared to their halide counterparts.
Conclusions:
- Aromatic sulfonate ligands can be effectively incorporated into octahedral molybdenum clusters, leading to novel functional materials.
- These complexes possess promising photoluminescent properties and the ability to generate singlet oxygen, suggesting potential applications in photodynamic therapy or sensing.
- The {Mo6I8}4+ core appears to be particularly advantageous for achieving high photoluminescence efficiency.
- The enhanced electrochemical stability of sulfonate-ligated complexes broadens their potential application scope in redox-active systems.
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