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13:21
Preparation, Purification, and Characterization of Lanthanide Complexes for Use as Contrast Agents for Magnetic Resonance Imaging
Published on: July 21, 2011
Non-innocent ligand effects on low-oxidation-state indium complexes.
Christopher J Allan1, Benjamin F T Cooper, Hugh J Cowley
1Department of Chemistry and Biochemistry, University of Windsor, 401 Sunset Avenue, Windsor, Ontario, N9B 3P4 (Canada).
Chemistry (Weinheim an Der Bergstrasse, Germany)
|September 17, 2013
Summary
Low oxidation state indium chemistry is stabilized by α-diimine ligands, forming discrete molecules or metallopolymers. This research overcomes indium disproportionation challenges, enabling novel coordination compounds.
Area of Science:
- Inorganic Chemistry
- Coordination Chemistry
- Materials Science
Background:
- Low oxidation state indium centers are prone to disproportionation, limiting stable coordination compound synthesis.
- Neutral ligand coordination to In(I) is challenging due to competing decomposition pathways.
Purpose of the Study:
- To explore the coordination chemistry of indium(I) triflate (InOTf) with α-diimine ligands.
- To investigate the structural and electronic properties of resulting indium complexes.
- To understand the factors influencing the formation of discrete molecules versus metallopolymers.
Main Methods:
- Synthesis and characterization of indium-α-diimine complexes.
- X-ray structural analysis to determine molecular and polymeric structures.
- Cyclic voltammetry and DFT studies to probe electronic properties and reactivity.
- Electron Paramagnetic Resonance (EPR) spectroscopy to investigate radical and spin states.
Main Results:
- Reaction of InOTf with N,N-dimesityl-2,3-dimethyl-diazabutadiene ((Mes)DAB(Me)) yielded a discrete molecular compound with a pyramidal In(I) center.
- Use of the less electron-rich N,N-dimesityl-diazabutadiene ((Mes)DAB(H)) ligand resulted in a metallopolymer linked by C-C and In-In bonds.
- Electronic studies suggest facile electron transfer to the (Mes)DAB(H) ligand.
- EPR studies revealed ligand-based radicals in solution and a spin triplet in the solid state.
Conclusions:
- α-Diimine ligands can stabilize low oxidation state indium, preventing disproportionation.
- The electronic properties of the α-diimine ligand dictate the formation of discrete molecular compounds or metallopolymers.
- The observed reactivity and structures offer new avenues for indium coordination chemistry and materials development.
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