scholarly journals Unravelling the mechanism of cobalt-catalysed remote C–H nitration of 8-aminoquinolinamides and expansion of substrate scope towards 1-naphthylpicolinamide

2020 ◽  
Vol 11 (2) ◽  
pp. 534-542
Author(s):  
Melody Chu ◽  
Oriol Planas ◽  
Anna Company ◽  
Xavi Ribas ◽  
Alex Hamilton ◽  
...  
Keyword(s):  
High Spin ◽  
Computational Studies ◽  
Radical Coupling

Computational studies of the Co-catalyzed remote nitration of 8-aminoquinolinamides have found the mechanism to operate through an unexpected high-spin induced remote radical-coupling.

Biocatalytic oligomerization of azoles; experimental and computational studies

2021 ◽  
Author(s):  
Neda Mashhadi ◽  
Keith E. Taylor ◽  
Nihar Biswas ◽  
Paul Meister ◽  
James W. Gauld
Keyword(s):  
Wastewater Treatment ◽  
Computational Studies ◽  
Soybean Peroxidase ◽  
Radical Coupling

Soybean peroxidase effectively transformed selected amino- and hydroxyl-azoles by radical coupling to dimers and trimers, showing feasibility for wastewater treatment.

scholarly journals SET activation of nitroarenes by 2-azaallyl anions as a straightforward access to 2,5-dihydro-1,2,4-oxadiazoles

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Dong Zou ◽  
Lishe Gan ◽  
Fan Yang ◽  
Huan Wang ◽  
Youge Pu ◽  
...  
Keyword(s):  
Transition Metal ◽  
Experimental Evidence ◽  
Radical Anion ◽  
Reaction Pathway ◽  
Cycloaddition Reaction ◽  
Electron Donors ◽  
Ring Closure ◽  
Computational Studies ◽  
Metal Free ◽  
Radical Coupling

AbstractThe use of nitroarenes as amino sources in synthesis is challenging. Herein is reported an unusual, straightforward, and transition metal-free method for the net [3 + 2]-cycloaddition reaction of 2-azaallyl anions with nitroarenes. The products of this reaction are diverse 2,5-dihydro-1,2,4-oxadiazoles (>40 examples, up to 95% yield). This method does not require an external reductant to reduce nitroarenes, nor does it employ nitrosoarenes, which are often used in N–O cycloadditions. Instead, it is proposed that the 2-azaallyl anions, which behave as super electron donors (SEDs), deliver an electron to the nitroarene to generate a nitroarene radical anion. A downstream 2-azaallyl radical coupling with a newly formed nitrosoarene is followed by ring closure to afford the observed products. This proposed reaction pathway is supported by computational studies and experimental evidence. Overall, this method uses readily available materials, is green, and exhibits a broad scope.

scholarly journals Imido Cobalt Complexes with Imidyl Character

2021 ◽  
Author(s):  
alexander Reckziegel ◽  
Manjinder Kour ◽  
Beatrice Battistella ◽  
Stefan Mebs ◽  
Katrin Beuthert ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Spin Density ◽  
High Spin ◽  
Bond Activation ◽  
High Spin State ◽  
Cobalt Complexes ◽  
Spectroscopic Methods ◽  
Computational Studies ◽  
Ancillary Ligand ◽  
Unpaired Spin

We report on the synthesis of a variety of trigonal imido cobalt complexes [Co(NAryl)L<sub>2</sub>)<sup>–</sup>, (L = N(Dipp)SiMe<sub>3</sub>), Dipp = 2,6-diisopropylphenyl) bearing very long Co–NAryl bonds of around 1.75 Å. The electronic structure was interrogated using a variety of physical and spectroscopic methods indicating the first authenticated examples of cobalt bound imidyl species. Computational studies corroborate these findings and reveal that the high-spin state of these complexes gives rise to unpaired spin-density on the imide nitrogen and leads to its imidyl character. Obtained complexes are capable of intermolecular H atom abstraction from C–H bonds that yields the corresponding cobalt amides. Exchange of the Dipp-substituent on the imide by the smaller mesityl function (2,4,6-trimethylphenyl) effectuates the unexpected Me<sub>3</sub>Si shift from the ancillary ligand set to the imide nitrogen, followed by intramolecular C–H bond activation.<br>

scholarly journals Spectroscopic and Computational Studies of a Series of High-Spin Ni(II) Thiolate Complexes

2010 ◽  
Vol 49 (14) ◽  
pp. 6535-6544 ◽  
Author(s):  
Katherine M. Van Heuvelen ◽  
Jaeheung Cho ◽  
Timothy Dingee ◽  
Charles G. Riordan ◽  
Thomas C. Brunold
Keyword(s):  
High Spin ◽  
Computational Studies ◽  
Thiolate Complexes

scholarly journals Imido Cobalt Complexes with Imidyl Character

2021 ◽  
Author(s):  
alexander Reckziegel ◽  
Manjinder Kour ◽  
Beatrice Battistella ◽  
Stefan Mebs ◽  
Katrin Beuthert ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Spin Density ◽  
High Spin ◽  
Bond Activation ◽  
High Spin State ◽  
Cobalt Complexes ◽  
Spectroscopic Methods ◽  
Computational Studies ◽  
Ancillary Ligand ◽  
Unpaired Spin

We report on the synthesis of a variety of trigonal imido cobalt complexes [Co(NAryl)L<sub>2</sub>)<sup>–</sup>, (L = N(Dipp)SiMe<sub>3</sub>), Dipp = 2,6-diisopropylphenyl) bearing very long Co–NAryl bonds of around 1.75 Å. The electronic structure was interrogated using a variety of physical and spectroscopic methods indicating the first authenticated examples of cobalt bound imidyl species. Computational studies corroborate these findings and reveal that the high-spin state of these complexes gives rise to unpaired spin-density on the imide nitrogen and leads to its imidyl character. Obtained complexes are capable of intermolecular H atom abstraction from C–H bonds that yields the corresponding cobalt amides. Exchange of the Dipp-substituent on the imide by the smaller mesityl function (2,4,6-trimethylphenyl) effectuates the unexpected Me<sub>3</sub>Si shift from the ancillary ligand set to the imide nitrogen, followed by intramolecular C–H bond activation.<br>

HFEPR and Computational Studies on the Electronic Structure of a High-Spin Oxidoiron(IV) Complex in Solution

2016 ◽  
Vol 55 (8) ◽  
pp. 3933-3945 ◽  
Author(s):  
Lukas Bucinsky ◽  
Gregory T. Rohde ◽  
Lawrence Que ◽  
Andrew Ozarowski ◽  
J. Krzystek ◽  
...  
Keyword(s):  
Electronic Structure ◽  
High Spin ◽  
Computational Studies

scholarly journals Structure and Reactivity of a High-Spin, Non-Heme Iron(III)-Superoxo Complex Supported by Phosphinimide Ligands

2021 ◽  
Author(s):  
Charles Winslow ◽  
Heui Beom Lee ◽  
Mackenzie J. Field ◽  
Simon J Teat ◽  
Jonathan Rittle
Keyword(s):  
Single Crystals ◽  
High Spin ◽  
Heme Iron ◽  
Computational Studies ◽  
Oxidation Processes ◽  
Transient Nature ◽  
Non Heme Iron ◽  
The Stability ◽  
Oxidation Chemistry ◽  
High Spin Iron

Non-heme iron oxygenases utilize dioxygen to accomplish challenging chemical oxidations. Further understanding of the Fe-O<sub>2</sub> intermediates implicated in these processes is challenged by their highly transient nature. To that end, we have developed a ligand platform featuring phosphinimide donors intended to stabilize oxidized, high-spin iron complexes. O<sub>2</sub> exposure of single crystals of a three-coordinate Fe(II) complex of this framework allowed for in crystallo trapping of a terminally-bound Fe-O<sub>2</sub> complex suitable for XRD characterization. Spectroscopic and computational studies of this species support a high-spin Fe(III) center antiferromagnetically coupled to a superoxide ligand, similar to that proposed for numerous non-heme iron oxygenases. In addition to the stability of this synthetic Fe-O<sub>2</sub> complex, its ability to engage in a range of stoichiometric and catalytic oxidation processes demonstrates that this iron-phosphinimide system is primed for development in modelling oxidizing bioinorganic intermediates and green oxidation chemistry.

scholarly journals Structure and Reactivity of a High-Spin, Non-Heme Iron(III)-Superoxo Complex Supported by Phosphinimide Ligands

2021 ◽  
Author(s):  
Charles Winslow ◽  
Heui Beom Lee ◽  
Mackenzie J. Field ◽  
Simon J Teat ◽  
Jonathan Rittle
Keyword(s):  
Single Crystals ◽  
High Spin ◽  
Heme Iron ◽  
Computational Studies ◽  
Oxidation Processes ◽  
Transient Nature ◽  
Non Heme Iron ◽  
The Stability ◽  
Oxidation Chemistry ◽  
High Spin Iron

Non-heme iron oxygenases utilize dioxygen to accomplish challenging chemical oxidations. Further understanding of the Fe-O<sub>2</sub> intermediates implicated in these processes is challenged by their highly transient nature. To that end, we have developed a ligand platform featuring phosphinimide donors intended to stabilize oxidized, high-spin iron complexes. O<sub>2</sub> exposure of single crystals of a three-coordinate Fe(II) complex of this framework allowed for in crystallo trapping of a terminally-bound Fe-O<sub>2</sub> complex suitable for XRD characterization. Spectroscopic and computational studies of this species support a high-spin Fe(III) center antiferromagnetically coupled to a superoxide ligand, similar to that proposed for numerous non-heme iron oxygenases. In addition to the stability of this synthetic Fe-O<sub>2</sub> complex, its ability to engage in a range of stoichiometric and catalytic oxidation processes demonstrates that this iron-phosphinimide system is primed for development in modelling oxidizing bioinorganic intermediates and green oxidation chemistry.

Evidence for high-spin-to-low-spin transition under pressure in Fe 72 Pt 28 Invar alloy

2000 ◽  
Vol 80 (2) ◽  
pp. 155-163 ◽  
Author(s):  
S. Odin, F. Baudelet, E. Dartyge, J. P
Keyword(s):  
High Spin ◽  
Spin Transition ◽  
Invar Alloy
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