4 research outputs found
A Bioinspired Zn<sup>II</sup>/Fe<sup>III</sup> Heterobimetallic Catalyst for Thia-Michael Addition
A novel tetranuclear Zn<sup>II</sup>/Fe<sup>III</sup> heterobimetallic
complex was synthesized, and the complex can efficiently catalyze
the Michael addition of thiophenols to ι,β-unsaturated
enones, even for tertiary carbonâsulfur bond formation
A Bioinspired Zn<sup>II</sup>/Fe<sup>III</sup> Heterobimetallic Catalyst for Thia-Michael Addition
A novel tetranuclear Zn<sup>II</sup>/Fe<sup>III</sup> heterobimetallic
complex was synthesized, and the complex can efficiently catalyze
the Michael addition of thiophenols to ι,β-unsaturated
enones, even for tertiary carbonâsulfur bond formation
Ambient Stable Trigonal Bipyramidal Copper(III) Complexes Equipped with an Exchangeable Axial Ligand
A stable trigonal bipyramidal copperÂ(III)
complex, [PPN]Â[CuÂ(<sup>TMS</sup>PS3)ÂCl] (<b>1</b>, wherein PPN
represents bisÂ(triphenylphosphine)Âiminium), was synthesized from CuCl<sub>2</sub>/PPNCl via intramolecular copperÂ(II) disproportionation. Under
ambient conditions, the axial chloride of <b>1</b> is exchangeable
in solution thus making <b>1</b> serve as an intermediate to
prepare trigonal bipyramidal copperÂ(III) derivatives, e.g., [PPN]Â[CuÂ(<sup>TMS</sup>PS3)Â(N<sub>3</sub>)] (<b>2</b>) and [CuÂ(<sup>TMS</sup>PS3)Â(DABCO)] (<b>3</b>). Diamagnetic complexes <b>1</b>â<b>3</b> were fully characterized by X-ray crystallography,
NMR, UVâvis, and Cu K-edge absorption spectroscopy. A series
of UVâvis titrations were performed to investigate the relative
ligand affinity toward the [CuÂ(<sup>TMS</sup>PS3)] moiety, verifying
the 1:1 binding equilibrium between various ligands. Compared to known
copperÂ(III) compounds, Cu K-edge absorptions of <b>1</b>â<b>3</b> possess lower pre-edge energy and higher shakedown transition
energy, which, respectively, attribute to the electron donation from <sup>TMS</sup>PS3<sup>3â</sup> ligand and their trigonal ligand
field
A Structurally Characterized Nonheme CobaltâHydroperoxo Complex Derived from Its Superoxo Intermediate via Hydrogen Atom Abstraction
Bubbling O<sub>2</sub> into a THF solution of Co<sup>II</sup>(BDPP)
(<b>1</b>) at â90 °C generates an O<sub>2</sub> adduct,
CoÂ(BDPP)Â(O<sub>2</sub>) (<b>3</b>). The resonance Raman and
EPR investigations reveal that <b>3</b> contains a low spin
cobaltÂ(III) ion bound to a superoxo ligand. Significantly, at â90
°C, <b>3</b> can react with 2,2,6,6-tetramethyl-1-hydroxypiperidine
(TEMPOH) to form a structurally characterized cobaltÂ(III)-hydroperoxo
complex, Co<sup>III</sup>(BDPP)Â(OOH) (<b>4</b>) and TEMPO<sup>â˘</sup>. Our findings show that cobaltÂ(III)-superoxo species
are capable of performing hydrogen atom abstraction processes. Such
a stepwise O<sub>2</sub>-activating process helps to rationalize cobalt-catalyzed
aerobic oxidations and sheds light on the possible mechanism of action
for Co-bleomycin