Bis(2-hy-droxy-2,3-di-hydro-1H-inden-1-aminium) tetra-chlorido-palladate(II) hemihydrate.

A new square-planar palladium complex salt hydrate, (C9H12NO)2[PdCl4]·0.5H2O, has been characterized. The asymmetric unit of the complex salt comprises two [PdCl4]2- dianions, four 2-hy-droxy-2,3-di-hydro-1H-inden-1-aminium cations, each derived from (1R,2S)-(+)-1-amino-indan-2-ol, and one water mol-ecule of crystallization. In the crystal, a two-dimensional layer parallel to (001) features a number of O-H⋯O, N-H⋯O, O-H⋯Cl and N-H⋯Cl hydrogen bonds.

Crystal structure of a phenoxyl radical complex relevant to the metal site of the galactose oxidase enzyme: A facile one-pot synthesis, evidence for hydrogen atom transfer and DNA cleavage via self-activation.

Copper complexes [Cu(L1H)ClO4] (1) and [Cu(L2)NO3] (2), which are relevant to the metal site of the galactose oxidase enzyme, were synthesized and characterized by different spectroscopic methods. L1H2 and L2H2 [where L1H2 stands for 2,2'-((1E,1'E)(2,2'-(pyridine-2,6-diyl)bis(2-phenylhydrazin-2-yl-1-ylidene))bis(methanylylidene))diphenol and L2H2 stands for 6,6'-((1E,1'E)-(2,2'-(pyridine-2,6-diyl)bis(2-phenylhydrazin-2-yl-1-ylidene))bis(methanylylidene))bis(2,4-di-tert-butylphenol), H stands for dissociable proton] are pentadentate ligands. These ligands provide pyridyl N, two imine N, and two non-innocent phenoxyl and phenolato O donors, forming complex 1 as a non-radical complex, while complex 2 is a phenoxyl radical complex. The molecular structures of complexes 1 and 2 were authenticated by X-ray crystallography. Benzyl alcohol oxidation was investigated, and the conversion of 9,10-dihydroanthracene to anthracene was examined to scrutinize the H-atom abstraction reaction. Nuclease activity with complexes 1 and 2 was investigated by self-activated plasmid DNA (pBR322) cleavage. Non-innocent properties of the ligand-containing phenolato function were investigated by DFT calculations.

Selective Formation of Mononuclear Palladium and Acetonitrile-Bridged Dinuclear Palladium Complexes Containing a Chiral Tridentate Ligand.

From the chiral Schiff base tridentate ligand LPh, unusual acetonitrile-bridged dinuclear palladium complex 1 and organopalladium complex 1' were synthesized selectively by using acetonitrile and ethanol, respectively. The chiral tridentate Schiff base ligand was bound to the palladium metal center with different chelation modes ([ONO] for 1 and [CNO] for 1'). Complex 1 constitutes the first example of dinuclear metal complexes connected only by a bridging acetonitrile, in which an exceptionally short C≡N bond distance [0.945(12) Å] of bridged acetonitrile was observed. To study the influence of a phenyl group attached to an imine, the phenyl-free ligand LH was prepared and used. In that case, an acetonitrile bridge was not observed. Theoretical calculation studies supporting the formation of 1 and 1' are favored.

The design of synthetic superoxide dismutase mimetics: seven-coordinate water soluble manganese(ii) and iron(ii) complexes and their superoxide dismutase-like activity studies.

Bio-inspired manganese [Mn(N5Py)(H2O)(CH3OH)](ClO4)2 (1) and iron [Fe(N5Py)(H2O)(ClO4)]ClO4 (2) complexes derived from a pentadentate ligand (N5Py = 2,6-bis((E)-1-phenyl-2-(pyridin-2-ylmethylene)hydrazinyl)pyridine) framework containing a N5 binding motif were synthesized and characterized using different spectroscopic methods. The molecular structures of complexes 1 and 2 were determined by X-ray crystallography. These complexes were found to be stable under physiological conditions and exhibited an excellent superoxide dismutase (SOD) activity. The SOD activity was determined by a xanthine-xanthine oxidase-nitro blue tetrazolium assay and the IC50 values were determined to be 1.53 and 2.09 µM, respectively.

Mn(II) based T1 and T2 potential MRI contrast agent appended with tryptamine: Recognition moiety for Aß-plaques.

We report the synthesis and characterization of manganese(II) complexes having pentadentate ligands L1 (2,6-bis(1-(2-phenyl-2-(pyridin-2-yl)hydrazono)ethyl)pyridine), L2 (methyl 2,6-bis((E)-1-(2-phenyl-2-(pyridin-2yl)hydrazono)ethyl)isonicotinate), L3 (N-(2-(1H-indol-3-yl)ethyl)-2,6-bis((E)-1-(2-phenyl-2-(pyridin2yl)hydrazono)ethyl)isonicotiamide) and their application as dual contrast agents for simultaneous T1 and T2 weighted magnetic resonance imaging. Single crystal analysis of all the complexes [MnIIL1, MnIIL2 and MnIIL3] confirm the formation of novel seven-coordinate manganese complexes with an inner sphere water and perchlorate ion. The Magnetic Resonance Imaging (MRI) contrast agent [MnL2] was further modified by incorporating tryptamine as a binding moiety specific to Amyloid Beta-fibrils (Aß-fibrils) in Alzhiemer's disease (AD) and it's in vitro evaluation for specific binding with Aß-fibrils indicated as a bio-marker of AD.