R oland Fröhlich

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Purple acid phosphatase is a widely distributed non-specific phosphomonoesterase. X-ray structures of the dimeric 111-kDa Fe(III)-Zn(II) kidney bean purple acid phosphatase (kbPAP) complexed with phosphate, the product of the reaction, and with tungstate, a strong inhibitor of the phosphatase activity, were determined at 2.7 and 3.0 angstroms resolution,(More)
Carbon dioxide is a gas that is changing our environment. Its role as a greenhouse gas is clear with the onset of global warming. In efforts to address this issue, ambitious and creative schemes are targeting materials including zeolites, silica gels, aluminas, and activated carbons, as well as sophisticated metal–organic frameworks (MOFs) for the benign(More)
An exceedingly sterically demanding, rigid, and chiral NHC ligand, IBiox[(-)-menthyl] (1), was prepared and structurally characterized. With a buried volume of approximately 50%, this ligand arguably represents one of the most sterically demanding monodentate ligands. The ability to use aryl chloride substrates in intramolecular palladium-catalyzed(More)
A new series of cationic blue-emitting, heteroleptic iridium(III)-based metal complexes were systematically synthesized using two 4,6-difluorophenylpyridine ligands as well as one methyl- or n-butyl-substituted bisimidazolium salt carbene-type ligand. In degassed CH(2)Cl(2), all complexes display highly efficient, blue phosphorescence (λ(max) ∼ 452 nm;(More)
Estrogenicity-directed fractionation of a methanol extract of the strobiles of Humulus lupulus that had been extracted previously with supercritical CO(2), known as "spent hops", led to the isolation and identification of 22 compounds including 12 prenylated chalcones (1-8, 10-13), five prenylflavanones (14-17), 4-hydroxybenzaldehyde (18),(More)
Amino alcohols are important synthons for N-heterocycles. We have developed an efficient method to activate hydroxyl groups, which avoids the use of toxic reagents and tolerates a wide variety of functional groups. Our strategy has been applied to the synthesis of functionalized p-methoxyphenyl-protected azetidines, pyrrolidines, and piperidines. The(More)
The ligands 4-7-H(2) were used in coordination studies with titanium(IV) and gallium(III) ions to obtain dimeric complexes Li(4)[(4-7)(6)Ti(2)] and Li(6)[(4/5a)(6)Ga(2)]. The X-ray crystal structures of Li(4)[(4)(6)Ti(2)], Li(4)[(5b)(6)Ti(2)], and Li(4)[(7a)(6)Ti(2)] could be obtained. While these complexes are triply lithium-bridged dimers in the solid(More)
The series of phosphine-borane adducts, Ph2(H3C--C[triple chemical bond]C)P--B(C6F5)3 (8 c), Ph(H3C--C[triple chemical bond]C)2P--B(C6F5)3 (8 b) and (H3C--C[triple chemical bond]C)3P--B(C6F5)3 (8 a), was prepared. The X-ray crystal structure analyses revealed close to eclipsed conformations for all members of this series with average dihedral angles(More)