0000000001303194

AUTHOR

Roland Krämer

showing 6 related works from this author

Coordination Diversity in Mono- and Oligonuclear Copper(II) Complexes of Pyridine-2-Hydroxamic and Pyridine-2,6-Dihydroxamic Acids

2013

Solution and solid state studies on Cu(II) complexes of pyridine-2-hydroxamic acid (HPicHA) and pyridine-2,6-dihydroxamic acid (H2PyDHA) were carried out. The use of methanol/water solvent allowed us to investigate the Cu(II)-HPicHA equilibria under homogeneous conditions between pH 1 and 11. In agreement with ESI-MS indication, the potentiometric data fitted very well with the model usually reported for copper(II) complexes of α-aminohydroxamate complexes ([CuL](+), [Cu5(LH-1)4](2+), [CuL2], [CuL2H-1](-)), however with much higher stability of the 12-MC-4 species. A series of copper(II) complexes has been isolated in the solid state and characterized by a variety of spectroscopic methods, …

Models MolecularDenticityPyridinesPotentiometric titrationInorganic chemistrychemistry.chemical_elementCrystallography X-RayHydroxamic AcidsMedicinal chemistryMagnetic susceptibilityCopperInorganic ChemistrySolventchemistry.chemical_compoundchemistryCoordination ComplexesPyridineChelationMethanolProtonsPhysical and Theoretical Chemistryta116CopperInorganic Chemistry
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Bis(3,5-dimethyl-1H-pyrazolyl)selenide--a new bidentate bent connector for preparation of 1D and 2D co-ordination polymers.

2007

The synthesis and description of eight polymeric complexes formed by transition metals with the bifurcated ligand bis(3,5-dimethyl-1H-pyrazolyl)selenide are discussed together with X-ray crystal analysis as well as variable temperature magnetic susceptibility and characterization by Mossbauer spectroscopy. Preferable types of binding patterns of the ligand were determined, which include a variation of the bridging modes (cis- and trans-) and of the separation length, where the latter parameter together with bending of the ligand molecule were found to be dependent on the type of co-ordination geometry of the central atom and the nature of the anion. A strategy for increasing the structure d…

chemistry.chemical_classificationDenticityBent molecular geometryInorganic chemistryPolymerMagnetic susceptibilityIonInorganic Chemistrychemistry.chemical_compoundCrystallographychemistryTransition metalSelenideMössbauer spectroscopyDalton transactions (Cambridge, England : 2003)
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New reaction of 1H-pyrazoles with selenium dioxide: one-pot synthesis of bis(1H-pyrazol-4-yl)selenides

2010

Abstract A novel reaction between 3- and 3,5-substituted pyrazoles with selenium dioxide proceeds with formation of bis(3R,5R′-1H-pyrazol-4-yl)selenides in high yield. On this basis, an efficient one-pot synthetic procedure has been developed. In the case of the unsubstituted pyrazole a selenonium compound has been obtained. The identity and structure of the isolated selenium derivatives have been confirmed by spectral methods and their molecular structures investigated by X-ray analysis.

Reaction mechanismOrganic ChemistryOne-pot synthesischemistry.chemical_elementCrystal structurePyrazoleBiochemistryChemical synthesisMedicinal chemistrychemistry.chemical_compoundNucleophilechemistryYield (chemistry)Drug DiscoveryOrganic chemistrySeleniumTetrahedron
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CCDC 867361: Experimental Crystal Structure Determination

2013

Related Article: Elzbieta Gumienna-Kontecka, Irina A. Golenya, Agnieszka Szebesczyk, Matti Haukka, Roland Krämer, and Igor O. Fritsky|2013|Inorg.Chem.|52|7633|doi:10.1021/ic4007229

Space GroupCrystallographycatena-[hexakis(mu3-pyridine-2-hydroxamato)-hexakis(22'-bipyridine)-bis(perchlorato)-nona-copper tetraperchlorate dimethyl sulfoxide solvate dihydrate]Crystal SystemCrystal StructureCell ParametersExperimental 3D Coordinates
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CCDC 867362: Experimental Crystal Structure Determination

2013

Related Article: Elzbieta Gumienna-Kontecka, Irina A. Golenya, Agnieszka Szebesczyk, Matti Haukka, Roland Krämer, and Igor O. Fritsky|2013|Inorg.Chem.|52|7633|doi:10.1021/ic4007229

Space GroupCrystallographyCrystal SystemCrystal StructureCell Parameterscatena-[(mu~4~-pyridine-26-dihydroxamato)-bis(22'-bipyridine)-bis(perchlorato)-di-copper NN-dimethylformamide solvate monohydrate]Experimental 3D Coordinates
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CCDC 867363: Experimental Crystal Structure Determination

2013

Related Article: Elzbieta Gumienna-Kontecka, Irina A. Golenya, Agnieszka Szebesczyk, Matti Haukka, Roland Krämer, and Igor O. Fritsky|2013|Inorg.Chem.|52|7633|doi:10.1021/ic4007229

Space GroupCrystallographyCrystal System(mu3-pyridine-26-dihydroxamato)-tris(NNN'N'-tetramethylethane-12-diamine)-tri-copper(ii) diperchlorateCrystal StructureCell ParametersExperimental 3D Coordinates
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