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Accessing Valuable Ligand Supports for Transition Metals: A Modified, Intermediate Scale Preparation of 1,2,3,4,5-Pentamethylcyclopentadiene
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Iridium Complexes with BIAN-Type Ligands: Synthesis, Structure and Redox Chemistry
Nikolai F Romashev1, Ivan V Bakaev1,2, Veronika I Komlyagina1,2
1Nikolaev Institute of Inorganic Chemistry SB RAS, Novosibirsk 630090, Russia.
International Journal of Molecular Sciences
|July 14, 2023
Summary
New iridium complexes with bis(diisopropylphenyl)iminoacenaphtene (dpp-bian) ligands were synthesized. The nitrosyl complex (2) is unstable, decomposing into iridium(II) species, which were characterized by EPR spectroscopy.
Area of Science:
- Organometallic Chemistry
- Coordination Chemistry
- Spectroscopy
Background:
- Iridium complexes are valuable in catalysis and materials science.
- Bis(diisopropylphenyl)iminoacenaphtene (dpp-bian) is a versatile ligand for transition metals.
Purpose of the Study:
- To synthesize and characterize novel iridium complexes with dpp-bian ligands.
- To investigate the structural, electrochemical, and magnetic properties of these complexes.
- To study the stability and decomposition pathways of the nitrosyl iridium complex.
Main Methods:
- Synthesis and characterization of iridium complexes.
- Spectroscopic techniques (NMR, IR, UV-Vis).
- Elemental analysis.
- X-ray diffraction analysis.
- Cyclic voltammetry (CV).
- Magnetochemical measurements.
- Electron Paramagnetic Resonance (EPR) spectroscopy.
- Density Functional Theory (DFT) calculations.
Main Results:
- Three iridium complexes, [Ir(cod)(dpp-bian)Cl] (1), [Ir(cod)(NO)(dpp-bian)](BF4)2 (2), and [Ir(cod)(dpp-bian)](BF4) (3), were successfully synthesized and characterized.
- Complexes 1-3 exhibit square-pyramidal geometry with a bent Ir-N-O bond in complex 2.
- Complex 2 is unstable in solution, decomposing to form complex 3 and a paramagnetic iridium(II) species (4).
- EPR spectroscopy confirmed the presence of a low-spin 5d7-Ir(II) state in the decomposition product.
Conclusions:
- The synthesized iridium-dpp-bian complexes display unique structural and electronic properties.
- The nitrosyl complex (2) demonstrates instability, highlighting potential reactivity pathways.
- The characterization of the iridium(II) decomposition product provides insights into redox behavior and electronic structure.
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