A5032458511- Crystallization and Solubility Studies
- X-ray Diffraction in Crystallography
- Organometallic Complex Synthesis and Catalysis
- Crystallography and molecular interactions
- Magnetism in coordination complexes
- Organoboron and organosilicon chemistry
- Lanthanide and Transition Metal Complexes
- Asymmetric Hydrogenation and Catalysis
- Boron Compounds in Chemistry
- Metal complexes synthesis and properties
- Coordination Chemistry and Organometallics
- Porphyrin and Phthalocyanine Chemistry
- Metal-Catalyzed Oxygenation Mechanisms
- Synthesis and characterization of novel inorganic/organometallic compounds
- Synthetic Organic Chemistry Methods
- Ferrocene Chemistry and Applications
- Electron Spin Resonance Studies
- Carbon dioxide utilization in catalysis
- Catalytic Cross-Coupling Reactions
- N-Heterocyclic Carbenes in Organic and Inorganic Chemistry
- Advanced NMR Techniques and Applications
- Radioactive element chemistry and processing
- Cyclopropane Reaction Mechanisms
- biodegradable polymer synthesis and properties
- Hydrogen Storage and Materials
Heidelberg University
2015-2025
Heidelberg (Poland)
2018
University of Freiburg
2017
Humboldt-Universität zu Berlin
2010
Centre National de la Recherche Scientifique
1995-2007
Universitat Rovira i Virgili
2007
Institut de Chimie
2007
Université de Montpellier
1995
Westfälische Hochschule
1965
Herein we report the synthesis and characterization of a dinuclear TbIII single-molecule magnet (SMM) with two [TbPc2]0 units connected via fused-phthalocyaninato ligand. The stable robust complex [(obPc)Tb(Fused-Pc)Tb(obPc)] (1) was characterized by using synchrotron radiation measurements other spectroscopic techniques (ESI-MS, FT-IR, UV). magnetic couplings between ions π radicals present in 1 were explored means density functional theory (DFT). Direct alternating current susceptibility...
Novel families of ultrahigh-molecular-weight polyethylene (UHMWPE) nanocomposites, containing uniformly dispersed, functionalized graphene (FG) nanosheets, were prepared by means the polymerization filling technique (PFT). Unparalleled any other carbon and boehmite FG/UHMWPE exhibited an unusual simultaneous improvement in stiffness, elongation at break, effective nucleation crystallization only 1 wt % FG content. nanosheets are ultrathin—with a thickness one atom lateral dimensions several...
The new paramagnetic quinolyl-functionalized Cp chromium(III) complexes 4−8, which serve as precursors for highly active olefin polymerization catalysts, have been synthesized and were investigated together with the known 1−3 by 1H NMR. Full assignment of observed NMR signals in these systems was achieved comparison different spectra spin unrestricted density functional calculations (UB3LYP level) Fermi contact term at hydrogen atoms. All geometries optimized using experimentally determined...
Polarity of H+ reversed: The synthesis [B2H3(hpp)2]+I−,a dinuclear borohydride with terminal and bridging H atoms (see picture; B yellow, N blue, C gray, white, I purple), is made possible the ligand hexahydropyrimidopyrimidate (hpp). In course reaction proton converted into a hydride. Detailed facts importance to specialist readers are published as ”Supporting Information”. Such documents peer-reviewed, but not copy-edited or typeset. They available submitted by authors. Please note:...
A series of functionalized diaza- and tetraazatetracenes was synthesized, either by condensation an aromatic diamine with ortho-quinone/diethyloxalate followed chlorination POCl(3) to give diazatetracenes or palladium-catalyzed coupling a phenylenediamine various 2,3-dichloroquinoxalines (after oxidation MnO(2)). Representative examples included halogenated nitrated derivatives. The optical properties these azatetracenes were discussed respect their molecular structures substitution...
Tailored polyethylene reactor blend additives (RB) with ultrabroad bimodal molar mass distributions comprise nanophase-separated ultrahigh (UHMWPE) uniformly dispersed in wax. During injection molding of high-density (HDPE) together variable amounts the HDPE wax/UHMWPE (70/30) additive (RB30) flow-induced oriented crystallization affords shish-kebab fiber-like UHMWPE nanostructures accounting for efficient self-reinforcement. RB are readily prepared by ethylene polymerization on...
Several small paramagnetic complexes combine large hyperfine NMR shifts with magnetic anisotropies. The latter are a prerequisite for single molecule magnet (SMM) behavior. We choose the SMM tris(octabutoxyphthalocyaninato) diterbium (1) high resolution study where we combined first time comprehensive (1)H and (13)C chemical shift analysis of evaluation residual dipolar couplings (RDCs). consequence partial alignment 1 in strong field spectrometer. To best our knowledge RDCs SMMs have never...
The catalytic ethylene polymerization on dual-site catalysts, supported functionalized graphene, enables nanostructure formation in polyethylene reactor blends by situ of uniformly dispersed ultrahigh molecular weight (UHMWPE) nanoplatelets and formed aligned UHMWPE shish-kebab nanofibers. For tailoring bimodal molar mass distributions, the quinolylsilylcyclopentadienylchromium(III) complex (Cr-1), producing with Mw > 3 × 106 g mol–1, is blended together bisiminopyridine complexes either...
The high-mobility group box 1 (HMGB1) protein has a central role in immunological antitumour defense. Here we show that natural killer cell-derived HMGB1 directly eliminates cancer cells by triggering metabolic cell death. allosterically inhibits the tetrameric pyruvate kinase isoform M2, thus blocking glucose-driven aerobic respiration. This results rapid shift forcing to rely solely on glycolysis for maintenance of energy production. Cancer can acquire resistance increasing using dimeric...
Abstract The present work describes the reaction of triplet dioxygen with porphyrinogenic calix[4]pyrrolato aluminates to alkylperoxido in high selectivity. Multiconfigurational quantum chemical computations disclose mechanism for this spin‐forbidden process. Despite a negligible spin–orbit coupling constant, intersystem crossing (ISC) is facilitated by singlet and state degeneracy spin–vibronic coupling. formed peroxides are stable toward external substrates but undergo an unprecedented...
Cyclopentadienyl ligands functionalized by quinoline or N,N-dimethylaniline have an ideal and rigid geometry for the formation of half-sandwich compounds. As a result, stable chromium(III) complexes 5−8 with intramolecular nitrogen coordination been obtained. Treatment MAO leads to highly active, temperature-stable catalysts polymerization ethylene.
Abstract Threefold symmetrical chiral podands may simplify the stereochemistry of key catalytic intermediates for cases in which they only act as bidentate ligands. This applies to systems chemical exchange between different κ 2 ‐coordinated forms takes place and non‐coordinated sidearm play a direct or indirect role at some earlier later stage cycle. Palladium(II)‐catalysed allylic substitutions provide appropriate test reactions along these lines. A series neutral dichloropalladium(II)...
Abstract Due to their high basicity, guanidines are versatile ligand systems. In principal, they could use both imino and amino nitrogen establish a dative metal–N bond. However, generally only the N of guanidine is bound metal. Herein we present some examples in which groups ligands directly engaged bonding metal ion. Under certain conditions group an additional link center acting as hemilabile ligand. This result likely be relevance for catalytic reactions, demonstrating possibility...
Abstract A ternary blend of the bisiminopyridine chromium (III) (Cr‐ 1 ) with iron (II) (Fe‐ 2 post‐metallocenes quinolylsilylcyclopentadienyl halfsandwich complex 3 was supported on mesoporous silica to produce novel multiple single‐site catalysts and polyethylene reactor blends tailor‐made molecular weight distributions (MWDs). The preferred cosupporting sequence this MAO‐treated Fe‐ followed by Cr‐ . Cosupporting does not impair nature components producing fractions $\overline M _{\rm w}$...
Condensation of phthalodinitrile and 2-amino-5,6,7,8-tetrahydroquinoline gave the bis(2-pyridylimino)isoindole protioligand 1 (thqbpiH) in high yield. Deprotonation thqbpiH (1) using LDA THF at −78 °C yields corresponding lithium complex [Li(THF)(thqbpi)] (2) which atom enforces almost planar arrangement tridentate ligand, with an additional molecule coordinated to Li. Reaction cobalt(II) chloride or iron(II) one equivalent 2 led formation metal complexes [CoCl(THF)(thqbpi)] (3a)...
A detailed nuclear magnetic resonance (NMR) study was carried out on a series of paramagnetic, tetrahedrally coordinated nickel(II) dihalide complexes featuring chelating guanidine ligands. complete assignment the NMR signals for all achieved by sophisticated experiments, including correlation spectra. The effects halide exchange, as well variation in guanidine-metal bite angles paramagnetic shifts, were assessed. shift derived with aid diamagnetic spectra analogous Zn complexes, which...
Guided by DFT based modeling the chemical shift range of a hydride resonance in proton nuclear magnetic (NMR) spectrum intermediate-spin, square planar iron complex tBu(PNP)Fe–H was predicted and detected as broad at −3560 ppm (295 K) with temperature dependent approximately 2000 between 223 383 K. The first detection metal-bonded hydrogen atom solution NMR paramagnetic ground state illustrates interplay theory experiment for characterization key components base metal catalysis.
A TbIII -phthalocyaninato double-decker ([1]0 ) single-molecule magnet (SMM) having four 15-crown-5 moieties in one of the ligands was synthesized, and its dimerization magnetic properties were studied an attempt to utilize supramolecular aggregation for enhancing SMM properties. Aggregation [1]0 form [12 K4 ]4+ presence K+ ions by using UV/Vis-NIR absorption NMR spectroscopies. For measurements, dispersed poly(methyl methacrylate) (PMMA). measurements on PMMA samples used track formation ....
Tailoring trimodal polyethylene (PE) molar mass distributions by means of ethylene polymerization on three-site catalysts, supported functionalized graphene (FG), enables nanophase separation during and melt processing, paralleled PE self-reinforcement. Typically, FG/MAO-supported catalysts combine bis(iminopyridyl)chromium trichloride (CrBIP), producing wax having high crystallization rate, quinolylcyclopentadienylchromium dichloride (CrQCp), forming in situ ultrahigh molecular weight...
This article summarizes the synthesis of cyclopentadienes, indenes, cyclopentadienyl ligands and indenyl which have a directly bonded aromatic or heteroaromatic substituent (HCpAr, HIndAr, Cp Ar, IndAr) a. Generally applicable procedures that allow specific introduction variety substituents are selected. Section 2.1 describes ring closure reactions precursors with lead to cyclopentadienes indenes. These routes may be used for chiral enantiopure ligands. In all other synthetic pathways,...
H+ umgepolt: Der Ligand Hexahydropyrimidopyrimidinat (hpp) ermöglichte die Synthese von [B2H3(hpp)2]+I−, einem zweikernigen Borhydrid mit endständigen und verbrückenden H-Atomen, dessen Struktur im Bild gezeigt ist (gelbgrün B, blau N, lila I). Dabei wird aus Proton ein Hydrid.
Abstract In this work we report on the synthesis of new zinc, magnesium and cationic aluminium alkyl as well Mg aryl complexes featuring chelating bisguanidine ligands [2,8‐bis(tetramethylguanidino)naphthalene (btmgn) 1,2‐bis(tetramethylguanidino)benzene (btmgb)]. The bond properties in are analyzed with a combination experiments quantum chemical calculations. VT NMR studies shed light fluxional processes within their activation barriers. compounds stable against alkylation C=N imine bonds...
The phthalocyaninato double-decker complexes [M(obPc)2 ](0) (M= Y(III) , Tb(III) Dy(III) ; obPc=2,3,9,10,16,17,23,24-octabutoxyphthalocyaninato), along with their reduced ([M(obPc)2 ](-) [P(Ph)4 ](+) M=Tb(III) ) and oxidized [SbCl6 (M=Y(III) counterparts were studied (1) H, (13) C 2D NMR. From the NMR data of neutral (i.e., one unpaired electron in ligands) anionic complexes, use dispersion corrected DFT methods, it was possible to separate metal-centered ligand-centered contributions...
Abstract The reaction between BF 3 ⋅ OEt 2 and one of two guanidines, 1,8‐bis(tetramethylguanidinyl)naphthalene (btmgn) 1,2,4,5‐tetrakis(tetramethylguanidinyl)naphthalene (ttmgn), yields the salts [(btmgn)(BF )]BF 4 [(ttmgn)(BF ) ](BF . NMR spectroscopic data show that boron atoms in cation anion exchange case , but not rate constant for this was estimated to be s −1 at 80 °C solutions CH CN. These were subsequently used reduction dihalides Br or I give polyhalide salts. We report synthesis...