Abstract
The synthesis and electronic structure of reduced aryl-substituted bis(imino)pyridine manganese compounds have been explored. Stirring a THF slurry of [( iPrPDI)MnCl 2] { iPrPDI = 2,6-(2,6-iPr 2-C 6H 3N=CMe) 2C 5H 3N} with excess Na and catalytic (0.5 mol-%) naphthalene furnished the bis(THF) compound [( iPrPDI)Mn(THF) 2]. Performing the reduction with excess Na(Hg) in toluene furnished the bis(chelate) manganese compound [( iPrPDI) 2Mn]. For both compounds, a combination of EPR spectroscopy, magnetic measurements and metrical parameters determined from X-ray diffraction established high-spin Mn II compounds with reduced, redox-active bis(imino)pyridine ligands. Substitution of the THF ligands with carbon monoxide yielded [( iPrPDI)Mn(CO) 2], a low-spin Mn I, d 6 compound with an experimentally observed bis(imino)pyridine-centred radical. Oxidation and reduction of this compound furnished [( iPrPDI)Mn(CO) 3] + and [( iPrPDI)Mn(CO) 2] -, respectively, and provided a series of three manganese carbonyl compounds over three oxidation states. Elucidation of the electronic structure of these compounds established that oxidation events within the series are ligand-rather than manganese-based, most likely a result of the stable low-spin Mn I, d 6 electron configuration imparted by the strong-field carbonyl ligands.
Original language | English (US) |
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Pages (from-to) | 535-545 |
Number of pages | 11 |
Journal | European Journal of Inorganic Chemistry |
Issue number | 3 |
DOIs | |
State | Published - Jan 2012 |
All Science Journal Classification (ASJC) codes
- Inorganic Chemistry
Keywords
- Catalysts
- Chelates
- Manganese
- Non-innocent ligands
- Redox chemistry