Dalton Transactions

doi: 10.1039/c002224cpmid: N/A

doi: 10.1039/c002227fpmid: N/A

doi: 10.1039/c002228bpmid: N/A

Perez, Lissette R.; Franz, Katherine J.

doi: 10.1039/b919237apmid: 20162187

Neurodegenerative diseases like Alzheimer's and Parkinson's disease are associated with elevated levels of iron, copper, and zinc and consequentially high levels of oxidative stress. Given the multifactorial nature of these diseases, it is becoming evident that the next generation of therapies must have multiple functions to combat multiple mechanisms of disease progression. Metal-chelating agents provide one such function as an intervention for ameliorating metal-associated damage in degenerative diseases. Targeting chelators to adjust localized metal imbalances in the brain, however, presents significant challenges. In this perspective, we focus on some noteworthy advances in the area of multifunctional metal chelators as potential therapeutic agents for neurodegenerative diseases. In addition to metal chelating ability, these agents also contain features designed to improve their uptake across the blood–brain barrier, increase their selectivity for metals in damage-prone environments, increase antioxidant capabilities, lower Aβ peptide aggregation, or inhibit disease-associated enzymes such as monoamine oxidase and acetylcholinesterase.

Long, Jérôme; Chamoreau, Lise-Marie; Marvaud, Valérie

doi: 10.1039/b924644bpmid: 20162188

The synthesis, the structural characterization and the magnetic properties of a heterotrimetallic decanuclear square, [(Mo(CN)8)2(CuLTb)4)]4+, noted MoCuTb, are described. This supramolecular compound, viewed as the first example of a metal-capped square, behaves as a single molecule magnet with a magnetic anisotropic barrier energy of Ueff = 13.40 cm−1 (19.25 K).

Akutagawa, Tomoyuki; Sato, Daisuke; Ye, Qiong; Noro, Shin-ichiro; Nakamura, Takayoshi

doi: 10.1039/b920600kpmid: 20162189

Ferromagnetic coupling of the [Ni(dmit)2]− anion layer through lateral sulfur–sulfur interactions along the short-axis of the anion was achieved using the flexible supramolecular cation of (m-fluoroanilinium+)(meso-dicyclohexano[18]crown-6).

de Silva, Namal; Solovyov, Andrew; Katz, Alexander

doi: 10.1039/b922300bpmid: 20162190

Isolated and patterned assemblies of Ir4-based metal polyhedra are described, in which a coordinated calixarene phosphine ligand enforces the desired cluster organization. The compounds are characterized by single-crystal X-ray diffraction and infrared spectroscopy.

Boča, Roman; Šalitroš, Ivan; Kožíšek, Jozef; Linares, Jorge; Moncoľ, Ján; Renz, Franz

doi: 10.1039/b919120hpmid: 20162191

The complex [FeII{(CN)FeIIIL5}6]Cl2 consists of a mixed-valence heptanuclear cyanide-bridged unit formed of a Schiff-base pentadentate ligand L5 and it shows a spin crossover of the peripheral FeIII centres.

Coleman, Anthony C.; Boyle, Nicola M.; Long, Conor; Augulis, Ramunas; Pugzlys, Audrius; van Loosdrecht, Paul H. M.; Browne, Wesley R.; Feringa, Ben L.; Ronayne, Kate L.; Pryce, Mary T.

doi: 10.1039/b925349cpmid: 20162192

González, Juan Carlos; García, Silvia; Bellú, Sebastián; Peregrín, Juan Manuel Salas; Atria, Ana María; Sala, Luis Federico; Signorella, Sandra

doi: 10.1039/b915652fpmid: 20162193

When excess uronic acid over CrVI is used, the oxidation of d-glucuronic acid (Glucur) by CrVI yields D-glucaric acid (Glucar) and CrIII as final products. The redox reaction involves the formation of intermediate CrIV and CrV species, with CrVI and CrV reacting with Glucur at comparable rates. The rate of disappearance of CrVI, and CrV increases with [H+] and [substrate]. The experimental results indicated that CrIV is a very reactive intermediate since its disappearance rate is much faster than CrVI/CrV and decreases when [H+] rises. Even at high [H+] CrIV intermediate was involved in fast steps and does not accumulate in the reaction. Kinetic studies show that the redox reaction between Glucur and CrVI proceeds through a mechanism combining one- and two-electron pathways for the reduction of intermediate Cr(iv) by the organic substrate: CrVI→ CrIV→ CrII and CrVI→ CrIV→ CrIII. The mechanism is supported by the observation of free radicals, CrO22+ (superoxoCrIII ion) and CrV as reaction intermediates. The EPR spectra show that five-co-ordinate oxo-CrV bischelates are formed at pH ≤ 4 with the uronic acid bound to CrV through the carboxylate and the α-OH group of the furanose form. Five-co-ordinated oxo-CrV monochelates are observed as minor species in addition to the major five-co-ordinated oxo-CrV bischelates. At pH 7.5 the EPR spectra show the formation of a CrV complex where the cis-diol groups of Glucur participate in the bonding to CrV.In vitro, our studies on the chemistry of CrV complexes can provide information on the nature of the species that are likely to be stabilized in vivo. In particular, the EPR pattern of Glucur-CrV species can be used as a finger print to identify CrV complexes formed in biological systems.