A5088650187- Crystallization and Solubility Studies
- X-ray Diffraction in Crystallography
- Polyoxometalates: Synthesis and Applications
- Metal-Organic Frameworks: Synthesis and Applications
- Magnetism in coordination complexes
- Lanthanide and Transition Metal Complexes
- Nanocluster Synthesis and Applications
- Crystallography and molecular interactions
- Vanadium and Halogenation Chemistry
- Advanced Nanomaterials in Catalysis
- Metal complexes synthesis and properties
- Inorganic Chemistry and Materials
- Organometallic Complex Synthesis and Catalysis
- Advanced NMR Techniques and Applications
- Metal-Catalyzed Oxygenation Mechanisms
- Molecular Junctions and Nanostructures
- Advanced Condensed Matter Physics
- Catalysis and Oxidation Reactions
- Chemical Synthesis and Reactions
- Metalloenzymes and iron-sulfur proteins
- Quantum and electron transport phenomena
- Porphyrin and Phthalocyanine Chemistry
- Organic and Molecular Conductors Research
- Graphene research and applications
- Physics of Superconductivity and Magnetism
RWTH Aachen University
2016-2025
Jülich Aachen Research Alliance
2015-2025
Forschungszentrum Jülich
2016-2025
Czech Academy of Sciences, Institute of Inorganic Chemistry
2023
Ernst Ruska Centre
2010-2021
FH Aachen
2014-2021
Grunberger Diabetes Institute
2015-2021
Institute of Inorganic Chemistry of the Slovak Academy of Sciences
2009-2019
Stadtwerke Jülich (Germany)
2014-2019
Imam Abdulrahman Bin Faisal University
2019
Oxidation without organics: A tetraruthenium polyoxometalate (see picture; Ru blue, O red, Si yellow, W black) catalyzes the rapid oxidation of H2O to O2 in water at ambient temperature, and shows considerable stability under turnover conditions. The complex was characterized by several methods, including X-ray crystallography cyclic voltammetry.
Pythagorean harmony can be found in the spherical polyoxometalate clusters described here (see illustration for an example of a structure), since there are interesting relationships between so-called magic numbers (12, 32, 42, 72, 132) relevant viruses and number building blocks cluster. The size these Keplerate tailored by varying type connections pentagons means different spacers.
An all-inorganic, oxidatively and thermally stable, homogeneous water oxidation catalyst based on redox-active (vanadate(V)-centered) polyoxometalate ligands, Na10[Co4(H2O)2(VW9O34)2]·35H2O (Na101-V2, sodium salt of the polyanion 1-V2), was synthesized, thoroughly characterized shown to catalyze in dark visible-light-driven conditions. This synthetic is exceptionally fast under mild conditions (TOF > 1 × 10(3) s(-1)). Under light-driven using [Ru(bpy)3](2+) as a photosensitizer persulfate...
Superparamagnetic iron oxide nanoparticles (SPION) are extensively used for magnetic resonance imaging (MRI) and particle (MPI), as well fluid hyperthermia (MFH). We here describe a sequential centrifugation protocol to obtain SPION with well-defined sizes from polydisperse starting formulation, synthesized using the routinely employed co-precipitation technique. Transmission electron microscopy, dynamic light scattering nanoparticle tracking analyses show that fractions obtained upon...
In polyoxometalate chemistry a large variety of compounds, clusters and solid-state structures can be formed by linking together metal–oxygen building blocks. Interestingly, reactions based on libraries virtual blocks planned under appropriate conditions, resulting for instance in the high-yield synthesis inorganic superfullerenes giant ring-shaped, electron-rich, mixed-valence polyoxomolybdates with nanosized cavities. The latter species continue to grow also covalently linked form chains...
Last night of the POMs: The title compound (X=GeIV) exhibits slow relaxation magnetization and quantum tunneling with a single-molecule magnetic behavior. Significant structural differences in [MnIII4MnII2O4(H2O)4]8+ cluster core X=SiIV analogue modify properties, thereby illustrating how polyoxometalate (POM) ligands can help systematic construction nanoscale magnets.
The largest inorganic molecular system so far, [(MoO3 )176 (H2 O)80 H32 ] (1; the picture on right shows polyhedral representation), which has been characterized by X-ray structure analysis, possesses a cavity of diameter 2.3 nm and remarkably stoichiometry (reduced) protonated hydrated "molecular molybdenum trioxide". It is formed reduction an aqueous solution lithium molybdate with tin(II) chloride at very high H+ concentrations.
Ohne Ligandenunterstützung: Der Aufbau des Titelsystems (siehe Bild; Ag violett, W blau, O rot) gelang mit den Bausteinen {H3W12O40}5− und {Ag2}2+. Dabei wurde ein mikroporöses Material [Ag(CH3CN)4]+-Ionen in seinen Kanälen erhalten. Einfache AgI⋅⋅⋅AgI-Wechselwirkungen sind maßgeblich für die Bildung Gerüsts, das bis zu 10 Gew.-% Acetonitril reversibel adorbieren kann.
The structural versatility characterizing polyoxometalate chemistry, in combination with the option to deliberately use well-defined building blocks, serves as foundation for generation of a large family magnetic clusters, frequently comprising highly symmetric spin arrays. If centers are coupled by antiferromagnetic exchange, some these systems exhibit frustration, which can result novel properties purely molecular origins. We discuss here selected nanosized clusters featuring triangles...
Light up the POMs: A luminescent lanthanoid complex with polyoxometalate (POM) and organic ligands has been structurally characterized (see picture). Comparison of this octanuclear TbIII 2-picolinate tungstoarsenate a dinuclear relative reveals role as chromophores, identifies Tb centers, determines relationship between POM coordination mode luminescence quenching.
Several key properties of the water oxidation catalyst Rb8K2[{RuIV4O4(OH)2(H2O)4}(γ-SiW10O36)2] and its mechanism are given. The one-electron oxidized analogue [{RuVRuIV3O6(OH2)4}(γ-SiW10O36)2]11− has been prepared thoroughly characterized. voltammetric rest potentials, X-ray structures, elemental analysis, magnetism, requirement an oxidant (O2) indicate these two complexes contain [RuIV4O6] [RuVRuIV3O6] cores, respectively. Voltammetry potentiometric titrations establish potentials several...
The first organic-inorganic hybrid complexes between CB[n] and polyoxometalates not only display a surprisingly high structural complementarity, the right pairing also allows their chemical physical properties to be coupled, as illustrated by two examples.
Oxidation ohne Organik: Ein Tetraruthenium-Polyoxometallat-Hybrid (siehe Bild; Ru blau, O rot, Si gelb, W schwarz) katalysiert die schnelle von H2O zu O2 bei Raumtemperatur. Der unter den Reaktionsbedingungen stabile Komplex wurde anderem kristallographisch und cyclovoltammetrisch charakterisiert.
In a nutshell: A 4.3 nm core–shell aggregate of 16 polyoxotungstate building units (see picture the W/Mn skeleton) delineates upper limit for structural complexity in molecular metal oxide cluster chemistry to date. This structure is defined by backbone network dual MnOW bridges; retroanalysis their formation suggests importance templation and kinetic control self-assembly {MnIII40WVI224} polyanion.
Small anion, big task: The assembly of a ten-component, heterochiral polyoxometalate aggregate, driven by the templating effect single phosphate proceeds through coordination-number-controlled formation route from three dimeric Dawson anion based magnetic building blocks.
Five members of a new family polyoxometalate (POM)-ligated tetranuclear rare earth metal complexes have been synthesized and characterized. These compounds the general formula (HDABCO)(8)H(5)Li(8)[Ln(4)As(5)W(40)O(144)(H(2)O)(10)(gly)(2)]·25H(2)O [Ln = Gd (1), Tb (2), Dy (3), Ho (4) Y (5), HDABCO monoprotonated 1,4-diazabicyclooctane, gly glycine] were from preformed POM precursor [As(2)W(19)O(67)(H(2)O)](14-). The structure is comprised two {As(2)W(19)O(68)} building blocks linked by unit...
Berkelium is positioned at a crucial location in the actinide series between inherently stable half-filled 5f(7) configuration of curium and abrupt transition chemical behavior created by onset metastable divalent state that starts californium. However, mere 320-day half-life berkelium's only available isotope, (249)Bk, has hindered in-depth studies element's coordination chemistry. Herein, we report synthesis detailed solid-state solution-phase characterization berkelium complex,...
Few-layer graphene possesses low-energy carriers that behave as massive Fermions, exhibiting intriguing properties in both transport and light scattering experiments. Lowering the excitation energy of resonance Raman spectroscopy down to 1.17 eV, we target these quasiparticles split bands close K point. The low weakens some processes are resonant visible, induces a clearer frequency-separation substructures 2D peak bi- trilayer samples. We follow excitation-energy dependence intensity each...
Complementary theoretical modeling methods are presented for the classical and quantum Heisenberg model to explain magnetic properties of nanometer-sized molecules. Excellent quantitative agreement is achieved between our experimental data down 0.1 K fields up 60 Tesla results giant Keplerate species {Mo72Fe30}, by far largest paramagnetic molecule synthesized date.
Big rings and nanocleavage: Whereas a variety of molybdenum oxide based nanoobjects can be obtained by self-assembly concomitant with modifications parent cluster system under alterable boundary conditions, drastic changes—comparable to molecular-scissors-type activity—can even cause splitting the (large) fragments which subsequently linked in fascinating ways option generating giant collectives (see picture {Mo}≡{MoO7(H2 O)}3−).
Unprecedented 18‐molybdosulfite Dawson clusters encapsulate two pyramidal sulfite ions as templates, and exhibit a short S⋅⋅⋅S interaction between the ions, which was characterized by DFT calculations. The [Mo 18 O 54 (SO 3 ) 2 ] 4− ion is first discrete thermochromic polyoxometalate cluster: its color varies from pale yellow at 77 K to deep red 500 (see picture).
A mixed-valence polyoxomolybdate cluster [H2MoVI12MoV4O52]10− was isolated by a new "shrink-wrapping" approach to trap clusters that display low symmetry and nonspherical topology (see scheme; HMTAH=protonated hexamethylenetetraamine). The unprecedented results from the restriction of reorganization framework more symmetrical clusters, yet it reacts with electrophiles, such as FeII.