4 research outputs found
Cobalt in a Bis-Ī²-diketiminate Environment
The reaction of Co<sub>2</sub>(mesityl)<sub>4</sub> with
acetonitrile
leads to the formation of a planar, low spin, bis-Ī²-diketiminate
cobaltĀ(II) complex, (1-mesitylbutane-1,3-diimine)<sub>2</sub>Co (<b>1</b>). EPR spectroscopy, magnetic studies, and DFT calculations
reveal the CoĀ(II) ion to reside in a tetragonal ligand field with
a <sup>2</sup>B<sub>2</sub>(d<sub><i>yz</i></sub>)<sup>1</sup> ground state electronic configuration. Oxidation of <b>1</b> with ferrocenium hexafluorophosphate furnishes (1-mesitylbutane-1,3-diimine)<sub>2</sub>CoĀ(THF)<sub>2</sub>PF<sub>6</sub> (<b>2</b>). The absence
of significant changes in the metalāligand bond metrics of
the X-ray crystal structures of <b>1</b> and <b>2</b> supports
ligand participation in the oxidation event. Moreover, no significant
changes in CāC or CāN bond lengths are observed by X-ray
crystallography upon oxidation of a Ī²-diketiminate ligand, in
contrast to typical redox noninnocent ligand platforms
Cobalt in a Bis-Ī²-diketiminate Environment
The reaction of Co<sub>2</sub>(mesityl)<sub>4</sub> with
acetonitrile
leads to the formation of a planar, low spin, bis-Ī²-diketiminate
cobaltĀ(II) complex, (1-mesitylbutane-1,3-diimine)<sub>2</sub>Co (<b>1</b>). EPR spectroscopy, magnetic studies, and DFT calculations
reveal the CoĀ(II) ion to reside in a tetragonal ligand field with
a <sup>2</sup>B<sub>2</sub>(d<sub><i>yz</i></sub>)<sup>1</sup> ground state electronic configuration. Oxidation of <b>1</b> with ferrocenium hexafluorophosphate furnishes (1-mesitylbutane-1,3-diimine)<sub>2</sub>CoĀ(THF)<sub>2</sub>PF<sub>6</sub> (<b>2</b>). The absence
of significant changes in the metalāligand bond metrics of
the X-ray crystal structures of <b>1</b> and <b>2</b> supports
ligand participation in the oxidation event. Moreover, no significant
changes in CāC or CāN bond lengths are observed by X-ray
crystallography upon oxidation of a Ī²-diketiminate ligand, in
contrast to typical redox noninnocent ligand platforms
Iron in a Trigonal Tris(alkoxide) Ligand Environment
Mononuclear
FeĀ(II) and FeĀ(III) complexes residing in a trigonal trisĀ(ditox) (ditox
= <sup>t</sup>Bu<sub>2</sub>(Me)ĀCO<sup>ā</sup>) ligand environment
have been synthesized and characterized. The FeĀ(III) ditox complex
does not react with oxidants such as PhIO, whereas NMe<sub>3</sub>O substitutes a coordinated tetrahydrofuran (THF) in the apical position
without undergoing oxo transfer. In contrast, the FeĀ(II) ditox complex
reacts rapidly with PhIO or Me<sub>3</sub>NO in THF or cyclohexadiene
to furnish a highly reactive intermediate, which cleaves CāH
bonds to afford the FeĀ(III)āhydroxide complex. When generated
in 1,2-difluorobenze, this intermediate can be intercepted to oxidize
phosphines to phosphine oxide. The fast rates at which these reactions
occur is attributed to a particularly weak ligand field imparted by
the trisĀ(alkoxide) ancillary ligand environment
Iron in a Trigonal Tris(alkoxide) Ligand Environment
Mononuclear
FeĀ(II) and FeĀ(III) complexes residing in a trigonal trisĀ(ditox) (ditox
= <sup>t</sup>Bu<sub>2</sub>(Me)ĀCO<sup>ā</sup>) ligand environment
have been synthesized and characterized. The FeĀ(III) ditox complex
does not react with oxidants such as PhIO, whereas NMe<sub>3</sub>O substitutes a coordinated tetrahydrofuran (THF) in the apical position
without undergoing oxo transfer. In contrast, the FeĀ(II) ditox complex
reacts rapidly with PhIO or Me<sub>3</sub>NO in THF or cyclohexadiene
to furnish a highly reactive intermediate, which cleaves CāH
bonds to afford the FeĀ(III)āhydroxide complex. When generated
in 1,2-difluorobenze, this intermediate can be intercepted to oxidize
phosphines to phosphine oxide. The fast rates at which these reactions
occur is attributed to a particularly weak ligand field imparted by
the trisĀ(alkoxide) ancillary ligand environment