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The Synthesis, Characterization and Reactivity of a Series of Ruthenium N-triphosPh Complexes
Published on: April 10, 2015
Solid state and solution structures of rhodium and iridium poly(pyrazolyl)borate diene complexes.
Christopher J Adams1, Kirsty M Anderson, Jonathan P H Charmant
1School of Chemistry, University of Bristol, Cantock's Close, Bristol, UK BS8 1TS.
Dalton Transactions (Cambridge, England : 2003)
|August 9, 2008
Summary
Poly(pyrazolyl)borate complexes exhibit diverse coordination structures and fluxional behavior. Steric hindrance influences ligand coordination, while NMR and IR spectroscopy reveal bonding modes, impacting electrochemical properties and electron transfer reversibility.
Area of Science:
- Organometallic Chemistry
- Coordination Chemistry
- Spectroscopy
Background:
- Poly(pyrazolyl)borate ligands are versatile ancillary ligands in organometallic chemistry.
- Understanding ligand coordination and dynamics is crucial for predicting complex reactivity and properties.
Purpose of the Study:
- To investigate the structural diversity of poly(pyrazolyl)borate complexes with rhodium and iridium.
- To correlate structural features with spectroscopic and electrochemical behavior.
Main Methods:
- Synthesis and characterization of poly(pyrazolyl)borate complexes.
- Nuclear Magnetic Resonance (NMR) spectroscopy (1H, 11B).
- Infrared (IR) spectroscopy.
- Electrochemical techniques (cyclic voltammetry).
- Electron Spin Resonance (ESR) spectroscopy.
Main Results:
- Diverse kappa-coordination modes (kappa3, kappa2) were observed, influenced by steric hindrance.
- Fast ligand exchange was detected for less hindered complexes via NMR spectroscopy.
- 11B NMR and IR spectroscopy differentiated bonding modes of the Tp' ligand.
- Electrochemical oxidation reversibility varied with ligand structure and metal center.
- ESR studies provided insights into the electronic structure of oxidized Rh(II) species.
Conclusions:
- Steric and electronic factors dictate the coordination geometry and fluxionality of poly(pyrazolyl)borate complexes.
- Spectroscopic methods effectively probe ligand bonding and dynamics.
- Electrochemical properties are intrinsically linked to the structural adaptability of these complexes.
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