0000000000659028
AUTHOR
Julia Klanke
A novel Cu(II) dimer containing oxime-hydrazone Schiff base ligands with an unusual mode of coordination: Study of magnetic, autoreduction and solution properties
Abstract Synthesis of a new hydrazone based Schiff base ligand, 3-methylpyrazole-5-carbohydrazone of 2,3-butanedione monoxime (HL) is reported. The reaction of Cu(ClO4)2·6H2O with HL in any ratio in ethanol affords the dinuclear complex [CuL(EtOH)]2(ClO4)2·2H2O (1). An unusual coordination mode of the ligand was observed, in which the ligand forms stable six and five membered chelate rings around the metal centres without enolization of the carbonyl group of the hydrazone moiety. The same coordination behavior of the ligand was observed in its cobalt(III) complex. The reaction of CoCl2·6H2O in methanol with the ligand HL affords the mononuclear complex [CoL2]Cl (2). Both 1 and 2 were charac…
Beyond the Heisenberg Model: Anisotropic Exchange Interaction between a Cu-Tetraazaporphyrin Monolayer andFe3O4(100)
The exchange coupling of a single spin localized at the central ion of Cu-tetraazaporphyrin on a magnetite(100) surface has been studied using x-ray magnetic circular dichroism (XMCD). Sum rule analysis of the XMCD spectra results in Cu spin and orbital magnetic moments as a function of the applied external field at low temperatures (20 K). The exchange coupling is positive for magnetization direction perpendicular to the surface (ferromagnetic) while it is negative for in-plane magnetization direction (antiferromagnetic). We attribute the anisotropy of the Heisenberg exchange coupling to an orbitally dependent exchange Hamiltonian.
Analyzing the enforcement of a high-spin ground state for a metallacrown single-molecule magnet
We have studied element-selective magnetic properties of the hetero- and homometallic metallacrowns $\mathrm{Cu}{(\mathrm{II})}_{2}[12\ensuremath{-}{\mathrm{MC}}_{YN(Shi)}\ensuremath{-}4]$ ($Y=\text{Cu}$, Fe, in short ${\mathrm{CuCu}}_{4}$ and ${\mathrm{CuFe}}_{4}$). These metallacrowns comprise four Fe or Cu ions surrounding a central Cu ion. Using x-ray magnetic circular dichroism we have probed local symmetries, electronic configuration, orbital and spin magnetic moments of the magnetic ions. The ratio between the Cu and Fe moment of $\ensuremath{-}0.11$ is independent of temperature in the range of 15 K to 90 K. The Cu moment shows antiparallel to the Fe moment. For ${\mathrm{CuCu}}_{4}…
Synthesis, characterization, X-ray crystallography, and antimicrobial activities of Ni(II) and Cu(II) complexes with a salicylaldehyde-based thiosemicarbazone ligand
A new salicylaldehyde-based ‘ONS’ tridentate salicylaldehyde-N(4)-diethylthiosemicarbazone (H2SANEt2) has been synthesized and characterized by elemental analyses, mass, IR, and 1H NMR spectral parameters. The coordination mode of the synthesized ligand is reported by solid state isolation and physico-chemical identification of Ni(II) and Cu(II) complexes, [Ni(SANEt2)]2 (1) and [Cu(SANEt2)]2 (2). Both complexes are neutral and oxygen-bridged dinuclear species. The ligand is bideprotonated ‘ONS’ tridentate in both complexes. IR spectral data indicate that coordination of each metal of the two complexes occurs through phenolic oxygen, azomethine nitrogen, and thiolato sulfur. X-ray crystallog…
CCDC 903324: Experimental Crystal Structure Determination
Related Article: Nitis Chandra Saha, Rajesh Pradhan, Mousumi Das, Nasima Khatun, Debmalya Mitra, Amalesh Samanta, Alexandra M.Z. Slawin, Atish Dipankar Jana, Julia Klanke, Eva Rentschler|2014|J.Coord.Chem.|67|286|doi:10.1080/00958972.2014.880426
CCDC 903325: Experimental Crystal Structure Determination
Related Article: Nitis Chandra Saha, Rajesh Pradhan, Mousumi Das, Nasima Khatun, Debmalya Mitra, Amalesh Samanta, Alexandra M.Z. Slawin, Atish Dipankar Jana, Julia Klanke, Eva Rentschler|2014|J.Coord.Chem.|67|286|doi:10.1080/00958972.2014.880426