A5046300241- Metal complexes synthesis and properties
- Metal-Catalyzed Oxygenation Mechanisms
- Magnetism in coordination complexes
- X-ray Diffraction in Crystallography
- Crystallization and Solubility Studies
- Porphyrin and Phthalocyanine Chemistry
- Chemical and Physical Properties in Aqueous Solutions
- Spectroscopy and Quantum Chemical Studies
- Advanced Chemical Physics Studies
- Radioactive element chemistry and processing
- CO2 Reduction Techniques and Catalysts
- Molecular Junctions and Nanostructures
- Catalytic Alkyne Reactions
- Bone Tissue Engineering Materials
- Catalytic Processes in Materials Science
- Organometallic Complex Synthesis and Catalysis
- Electrochemical Analysis and Applications
- Catalytic C–H Functionalization Methods
- X-ray Spectroscopy and Fluorescence Analysis
- Electrocatalysts for Energy Conversion
- Electron and X-Ray Spectroscopy Techniques
- Crystal Structures and Properties
- Photochemistry and Electron Transfer Studies
- N-Heterocyclic Carbenes in Organic and Inorganic Chemistry
- Calcium Carbonate Crystallization and Inhibition
HUN-REN Wigner Research Centre for Physics
2016-2024
Swedish University of Agricultural Sciences
2018-2023
Hungarian Academy of Sciences
2016-2020
Uppsala University
2019
University of Szeged
2010-2015
Combined X-ray free-electron laser techniques pinpoints loci of intersections between potential energy surfaces a photo-excited 3d transition-metal centered molecule.
High energy resolution, hard X-ray spectroscopies are powerful element selective probes of the electronic and local structure matter, with diverse applications in chemistry, physics, biology materials science. The routine application these techniques is hindered by complicated slow access to synchrotron radiation facilities. Here we propose a new, economic, easily operated laboratory high resolution von H\'amos type spectrometer, which offers rapid transmission experiments for absorption,...
Disentangling the dynamics of electrons and nuclei during nonadiabatic molecular transformations remains a considerable experimental challenge. Here we have investigated photoinduced electron transfer following metal-to-ligand charge-transfer (MLCT) excitation [Fe(bmip)2]2+ photosensitizer, where bmip = 2,6-bis(3-methyl-imidazole-1- ylidine)-pyridine, with simultaneous femtosecond-resolution Fe K{\alpha} K\b{eta} X-ray Emission Spectroscopy (XES) Wide Angle Scattering (WAXS). This...
Amorphous calcium carbonate (ACC), with the highest reported specific surface area of all current forms (over 350 m2 g–1), was synthesized using a surfactant-free, one-pot method. Electron microscopy, helium pycnometry, and nitrogen sorption analysis revealed that this highly mesoporous ACC, pore volume ∼0.86 cm3 g–1 pore-size distribution centered at 8–9 nm, is constructed from aggregated ACC nanoparticles an estimated average diameter 7.3 nm. The porous remained amorphous retained its high...
By combining transient X-ray and optical studies, we reveal the solvent influence on excited state potential energy surfaces of [Fe(bpy)(CN)<sub>4</sub>]<sup>2−</sup>.
Iron N-heterocyclic carbene (NHC) complexes have received a great deal of attention recently because their growing potential as light sensitizers or photocatalysts. We present sub-ps X-ray spectroscopy study an FeII NHC complex that identifies and quantifies the states involved in deactivation cascade after absorption. Excited molecules relax back to ground state along two pathways: After population hot 3 MLCT state, from initially excited 1 30 % undergo ultrafast (150 fs) relaxation MC...
Amorphous calcium phosphate (ACP) has shown significant effects on the biomineralization and promising applications in bio-medicine. However, limited stability porosity of ACP material restrict its practical applications. A storage stable highly porous with Brunauer–Emmett–Teller surface area over 400 m2/g was synthesized by introducing phosphoric acid to a methanol suspension containing amorphous carbonate nanoparticles. Electron microscopy revealed that constructed aggregated nanoparticles...
The structures of the solvated copper(II) ion in water and nine organic oxygen donor solvents with similar electron-pair ability, but different space-demanding properties at coordination, have been studied by EXAFS. N,N'-Dimethylpropyleneurea N,N,N',N'-tetramethylurea are sufficiently space demanding coordination to make axial positions not accessible, resulting square-planar solvate complexes an intense green color. mean Cu-O bond distances these two 1.939(3) 1.935(3) Å, respectively. best...
We have employed a range of ultrafast X-ray spectroscopies in an effort to characterize the lowest energy excited state [Fe(dcpp)2]2+ (where dcpp is 2,6-(dicarboxypyridyl)pyridine). This compound exhibits unusually short excited-state lifetime for low-spin Fe(II) polypyridyl complex 270 ps room-temperature fluid solution, raising questions as whether ligand-field strength had pushed this system beyond 5T2/3T1 crossing point and stabilizing latter state. Kα Kβ emission been used unambiguously...
Alkaline solutions containing polyhydroxy carboxylates and Ca(II) are typical in cementitious radioactive waste repositories. Gluconate (Gluc–) is a structural functional representative of these sugar carboxylates. In the current study, structure equilibria complexes forming such strongly alkaline Ca2+ gluconate have been studied. It was found that Gluc– significantly increases solubility portlandite (Ca(OH)2(s)) under conditions unexpectedly high stability formed. The mononuclear (CaGluc+...
<italic>In situ</italic> XAS is used to reveal the evolution of palladium species during an undirected C–H acetoxylation reaction.
The identity of the predominating tin(ii)-hydroxide complex formed in hyper-alkaline aqueous solutions (0.2 ≤CNaOH≤ 12 mol dm(-3)) is determined by potentiometric titrations, Raman, Mössbauer and XANES spectroscopy, supplemented quantum chemical calculations. Thermodynamic studies using a H2/Pt electrode up to free hydroxide concentrations 1 dm(-3) showed presence single monomeric with tin(II) : ratio 3. This observation together Raman spectroscopic measurements mechanical calculations...
Abstract Iron N‐heterocyclic carbene (NHC) complexes have received a great deal of attention recently because their growing potential as light sensitizers or photocatalysts. We present sub‐ps X‐ray spectroscopy study an Fe II NHC complex that identifies and quantifies the states involved in deactivation cascade after absorption. Excited molecules relax back to ground state along two pathways: After population hot 3 MLCT state, from initially excited 1 30 % undergo ultrafast (150 fs)...
Time-resolved X-ray absorption spectroscopy has been utilized to monitor the bimolecular electron transfer in a photocatalytic water splitting system. This possible by uniting local probe and element specific character of transitions with insights from high-level ab initio calculations. The target heteroleptic [IrIII (ppy)2 (bpy)]+ photosensitizer, combination triethylamine as sacrificial reductant Fe3(CO)12 reduction catalyst. relevant molecular have characterized via high-resolution Ir...
The properties of transition-metal complexes and their chemical dynamics can be effectively modified with ligand substitutions, theory a great aid to such molecular engineering. In this paper, we first theoretically explored how substitution Cl atom at different positions the terpyridine affects electronic structure [Fe(terpy)2]2+ complex. We found that besides position 4′, next most promising candidate cause substantial effects is where side pyridine ring substituted 5 (β). Therefore, next,...
XPS studies have used to study the speciation and relative position of alkyl carboxylic acids conjugated carboxylates water air–air interface. The transport ammonia small from air show that equilibria between aqueous bulk surface region establish fast.
Even quite simple chemical systems can involve many components and states, sometimes it be very difficult to differentiate them by their hardly separable physical-chemical properties. The NiII-EDTA-CN- (EDTA = ethylenediaminetetraacetic acid) ternary system is a good example for this problem where, in spite of its fairly numerous investigations, several molecular combinations exist, all not having been identified unambiguously yet. In order achieve detailed understanding the reaction steps...
The activation process of a known Ru-catalyst, dicarbonyl(pentaphenylcyclopentadienyl)ruthenium chloride, has been studied in detail using time resolved situ X-ray absorption spectroscopy. data provide bond lengths the species involved as well information about formation and breaking. On addition potassium tert-butoxide, catalyst is activated an alkoxide complex formed. proceeds via key acyl intermediate, which gives rise to complete structural change coordination environment around Ru atom....
The effect of substitution in the axial 4' position by electron withdrawing (EW) and donating (ED) groups on ground excited state properties \feterpy complex is investigated a systematic study. DFT calculations are used to determine geometric electronic structures substituted complexes, these calculated results were compared experimental from stationary time-resolved spectroscopy. question how this interplay theory experiment can be context ligand engineering also considered.
In hyper-alkaline aqueous solutions, lead(<sc>ii</sc>) is present exclusively as [Pb(OH)<sub>3</sub>]<sup>−</sup>. Other species, like [Pb(OH)<sub>4</sub>]<sup>2−</sup>, [PbOOH]<sup>−</sup>or [PbO<sub>2</sub>]<sup>2−</sup>are not detectable.
A well-studied heterogeneous palladium(II) catalyst used for the cycloisomerization of acetylenic acids is known to be susceptible deactivation through reduction. To gain a deeper understanding this process and enable design reactivation strategy, in situ X-ray absorption spectroscopy (XAS) was used. With technique, changes palladium oxidation state coordination environment could studied close detail, which provided experimental evidence that primarily caused by triethylamine-promoted...