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Heterovalent, Homometallic Rings: Synthesis, Optical, and EPR Studies of {TiIV 7TiIII} Complexes
Selena J Lockyer1, Lubomir Loci1, Yingzhao Ma1
1Department of Chemistry and Photon Science Institute, The University of Manchester, Manchester, England.
Chemistry (Weinheim an Der Bergstrasse, Germany)
|July 18, 2026
Summary
Researchers synthesized new titanium ring complexes with mixed-valence {TiIV7TiIII} cores. These complexes exhibit unique electronic properties and potential applications in photocatalysis, showing longer spin relaxation times than chromium-nickel analogs.
Area of Science:
- Inorganic Chemistry
- Materials Science
- Photochemistry
Background:
- Heterovalent, homometallic ring complexes are of interest for their unique electronic and magnetic properties.
- Titanium complexes, in particular, offer potential in catalysis and materials science.
Purpose of the Study:
- To report a new class of heterovalent, homometallic titanium ring complexes with {TiIV7TiIII} cores.
- To investigate their synthesis, electronic structure, and magnetic properties.
- To explore their potential relevance in photocatalysis.
Main Methods:
- Synthesis of novel titanium complexes using [Ti(OiPr)4], carboxylic acids, and amine ligands.
- Photoreduction of titanium precursors to generate {TiIV7TiIII} rings.
- Characterization using UV-vis/NIR spectroscopy and Electron Paramagnetic Resonance (EPR) spectroscopy.
Main Results:
- Successful synthesis of new {TiIV7TiIII} ring complexes: [py-CH2NH2Et][Ti7TiO8(O2CR)16].
- UV-vis/NIR spectroscopy indicated Robin and Day Class II mixed-valent behavior at room temperature.
- EPR spectroscopy revealed a localized 3d1 (s = 1/2) configuration at low temperatures.
- Comparison with isostructural {CrIII7NiII} rings showed significantly longer spin lattice relaxation times (T1) and maintained phase memory (Tm) to higher temperatures for the titanium complexes.
Conclusions:
- A new class of heterovalent titanium ring complexes with {TiIV7TiIII} cores has been synthesized and characterized.
- These complexes exhibit interesting mixed-valent and magnetic properties, with potential for photocatalysis.
- The superior spin relaxation properties compared to Cr-Ni analogs suggest potential for quantum computing applications.
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