A5081835575- Metal-Catalyzed Oxygenation Mechanisms
- Crystallization and Solubility Studies
- X-ray Diffraction in Crystallography
- Metal complexes synthesis and properties
- Magnetism in coordination complexes
- Porphyrin and Phthalocyanine Chemistry
- Metalloenzymes and iron-sulfur proteins
- Oxidative Organic Chemistry Reactions
- CO2 Reduction Techniques and Catalysts
- Electrocatalysts for Energy Conversion
- Crystallography and molecular interactions
- Organic and Molecular Conductors Research
- Organometallic Complex Synthesis and Catalysis
- Synthesis and Catalytic Reactions
- Vanadium and Halogenation Chemistry
- Photosynthetic Processes and Mechanisms
- N-Heterocyclic Carbenes in Organic and Inorganic Chemistry
- Catalytic C–H Functionalization Methods
- Carbon dioxide utilization in catalysis
- Polyoxometalates: Synthesis and Applications
- Heme Oxygenase-1 and Carbon Monoxide
- Thermal and Kinetic Analysis
- Advanced Chemical Physics Studies
- Microbial metabolism and enzyme function
- Inorganic and Organometallic Chemistry
Humboldt-Universität zu Berlin
2016-2025
Ewha Womans University
2014
Technische Universität Berlin
2013
University of Minnesota
2006-2012
University of Minnesota, Duluth
2011
National High Magnetic Field Laboratory
2008
Florida State University
2008
Roosevelt University
2008
Max Planck Society
2004-2007
University of Vermont
2007
The reactivities of mononuclear nonheme iron(IV)-oxo complexes bearing different axial ligands, [Fe(IV)(O)(TMC)(X)](n+) [where TMC is 1,4,8,11-tetramethyl-1,4,8,11-tetraazacyclotetradecane and X NCCH(3) (1-NCCH(3)), CF(3)COO(-) (1-OOCCF(3)), or N(3)(-) (1-N(3))], [Fe(IV)(O)(TMCS)](+) (1'-SR) (where TMCS 1-mercaptoethyl-4,8,11-trimethyl-1,4,8,11-tetraazacyclotetradecane), have been investigated with respect to oxo-transfer PPh(3) hydrogen atom abstraction from phenol O H alkylaromatic C...
A series of transition metal complexes involving non-innocent o-dithiolene and o-phenylenediamine ligands has been characterized in detail by various spectroscopic methods like magnetic circular dichroism (MCD), absorption (abs), resonance Raman (rR), electron paramagnetic (EPR), sulfur K-edge X-ray spectroscopies. computational model for the electronic structure is then proposed based on density functional theory (DFT) or ab-initio methods, which can successfully account observed trends...
To fully characterize the CoIII–'nitrene radical' species that are proposed as intermediates in nitrene transfer reactions mediated by cobalt(II) porphyrins, different combinations of complexes porphyrins and reagents were combined, generated studied using EPR, UV–vis, IR, VCD, UHR-ESI-MS, XANES/XAFS measurements. Reactions 1P1 (P1 = meso-tetraphenylporphyrin (TPP)) 1P2 (P2 3,5-DitBu-ChenPhyrin) with organic azides 2Ns (NsN3), 2Ts (TsN3), 2Troc (TrocN3) led to formation mono-nitrene 3P1Ns,...
Abstract Terminal cobalt(IV)–oxo (Co IV –O) species have been implicated as key intermediates in various cobalt-mediated oxidation reactions. Herein we report the photocatalytic generation of a mononuclear non-haem [(13-TMC)Co (O)] 2+ ( 2 ) by irradiating [Co II (13-TMC)(CF 3 SO )] + 1 presence [Ru (bpy) ] , Na S O 8 and water an oxygen source. The intermediate was also obtained reacting with artificial oxidant (that is, iodosylbenzene) characterized spectroscopic techniques. In particular,...
The three diamagnetic square planar complexes of nickel(II), palladium(II), and platinum(II) containing two S,S-coordinated 3,5-di-tert-butylbenzene-1,2-dithiolate ligands, (LBu)2-, namely [MII(LBu)2]2-, have been synthesized. corresponding paramagnetic monoanions [MII(LBu)(LBu•)]- (S = 1/2) the neutral species [MII(LBu•)2] (M Ni, Pd, Pt) also generated in solution or solid state as [N(n-Bu)4][MII(LBu)(LBu•)] salts. complex [CuIII(LBu)2]- has investigated. studied by UV−vis, IR, EPR...
The bidentate ligands N-phenyl-o-phenylenediamine, H(2)((2)L(N)IP), or its analogue 2-(2-trifluoromethyl)anilino-4,6-di-tert-butylphenol, ((4)L(N)IP), react with [Co(II)(CH(3)CO(2))(2)]4H(2)O and triethylamine in acetonitrile the presence of air yielding square-planar, four-coordinate species [Co((2)L(N))(2)] (1) [Co((4)L(O))(2)] (4) an S=1/2 ground state. corresponding nickel complexes [Ni((4)L(O))(2)] (8) cobaltocene reduced form [Co(III)(Cp)(2)][Ni((4)L(O))(2)] (9) have also been...
The electronic structures of [M(L(Bu))(2)](-) (L(Bu)=3,5-di-tert-butyl-1,2-benzenedithiol; M=Ni, Pd, Pt, Cu, Co, Au) complexes and their electrochemically generated oxidized reduced forms have been investigated by using sulfur K-edge as well metal K- L-edge X-ray absorption spectroscopy. structure content the spectra was determined through detailed comparison experimental theoretically calculated spectra. calculations were based on a new simplified scheme quasi-relativistic time-dependent...
Abstract This review summarizes the properties of group 9–11 metal–oxo and metal–imido complexes, which have been either isolated or proposed as reactive intermediates in metal‐catalyzed organic transformations. We begin with a general description bonding transition‐metal–oxo –imido complexes various geometries, followed by discussion from groups 9–11. The focus this is to provide clear picture state art well insight towards potential future synthetic endeavors.
The electronic structures of two formally isoelectronic transition-metal dithiolato complexes [Fe(L)2]2- (1) and [Co(L Bu)2]1- (2) both possessing a spin triplet ground state (St=1) have been investigated by various spectroscopic density functional methods; H2L Bu represents the pro-ligand 3,5-di-tert-butylbenzene-1,2-dithiol is corresponding unsubstituted benzene-1,2-dithiol. An axial zero-field splitting (D) +32 cm(-1) for 2 has measured independently SQUID magnetometry, far-infrared...
Abstract High‐valent cobalt‐oxo intermediates are proposed as reactive in a number of cobalt‐complex‐mediated oxidation reactions. Herein we report the spectroscopic capture low‐spin ( S =1/2) Co IV ‐oxo species presence redox‐inactive metal ions, such Sc 3+ , Ce Y and Zn 2+ investigation their reactivity CH bond activation sulfoxidation Theoretical calculations predict that binding Lewis acidic ions to core increases electrophilicity oxygen atom, resulting redox tautomerism highly unstable...
Oxoiron(IV) species have been found to act as the oxidants in catalytic cycles of several mononuclear nonheme iron enzymes that activate dioxygen. To gain insight into factors govern oxidative reactivity such complexes, a series five synthetic S = 1 [Fe(IV)(O)(L(N5))](2+) complexes has characterized with respect their spectroscopic and electrochemical properties well relative abilities carry out oxo transfer hydrogen atom abstraction. The Fe=O units these are supported by neutral...
An elusive S=3/2 oxocobalt(IV) complex is stabilized by a Lewis acid interaction with scandium(III) ion. The {CoIV-O-Sc}3+ unit, characterized spectroscopic and DFT methods, stronger electron-transfer H-atom abstraction agent but weaker oxo-transfer than the corresponding {FeIVO} (see scheme; L=tris[2-(N-tetramethylguanidyl)ethyl]amine). Detailed facts of importance to specialist readers are published as "Supporting Information". Such documents peer-reviewed, not copy-edited or typeset....
High-valent copper–nitrene intermediates have long been proposed to play a role in copper-catalyzed aziridination and amination reactions. However, such eluded detection for decades, preventing the unambiguous assignments of mechanisms. Moreover, electronic structure has also controversially discussed literature. These mechanistic questions controversy provided tremendous motivation probe accessibility reactivity CuIII–NR/CuIIN•R species. In this paper, we report breakthrough field that was...
Ni(III)-intermediates are trapped by EPR and UV/Vis spectroscopy in the reaction of a Ni(II) salt with mCPBA. On basis their oxo-transfer hydrogen-atom abstraction abilities intermediates assigned as elusive terminal Ni(III)–oxo/hydroxo species. The findings suggest that Ni(III)–O(H) moieties viable reactants oxidation catalysis.
Herein, we report the formation of a highly reactive nickel-oxygen species that has been trapped following reaction Ni(II) precursor bearing macrocyclic bis(amidate) ligand with meta-chloroperbenzoic acid (HmCPBA). This compound is only detectable at temperatures below 250 K and much more toward organic substrates (i.e., C-H bonds, C=C sulfides) than previously reported well-defined species. Remarkably, this formed by heterolytic O-O bond cleavage Ni-HmCPBA precursor, which concluded from...
Abstract This study shows that the simple approach of keeping anodic TiO 2 nanotubes at 70 °C in ethanol for 1 h results improved photoelectrochemical water splitting activity due to initiation crystallization material amplified by light‐induced formation a Ti 3+ −V o states under UV 365 nm illumination. For first time, are generated when oxygen is present reaction solution and stable contact with air (oxygen) long time (two months). We confirmed here amorphous or nearly structure titania...