Alzheimer's Disease and Metals: A Review of the Involvement of Cellular Membrane Receptors in Metallosignalling

Alzheimer's disease (AD) is a debilitating form of dementia. The hallmark protein associated with the disease is the amyloid beta (Aβ) peptide. Aggregation of Aβ has been shown to depend on interactions with metals. The recent studies now demonstrate that metals also play additional important roles in the disease process. Consequently, there may be benefit from modulating metal homeostasis. However, the role and subcellular location of metals within neurons is not well understood. There is growing evidence to suggest that metals can act at the site of cellular membrane receptors and affect cellular signaling by modulating the signal transduction of those receptors. The glutamatergic and cholinergic receptor systems, both well-known neurotransmitter systems affected in AD, have well-documented metal interactions, as do the tropomyosin-receptor kinase (Trk) family of receptors and the epidermal growth factor (EGF) receptor. In this paper, the metal interactions with these membrane receptor systems will be explored and thus the potential for membrane receptors as an intervention point in AD will be assessed

Rational Synthesis of Linear and Branched Oligogermanes

Group 14 catenates are important because of their intrinsic optical and electronic properties which entirely depends on their structure. However, study of this structure-property relationship in germanium catenates have been less developed compared with silicon and tin analogues due to the lack of synthetic methods to provide the pure compounds in high yield. The purpose of this study was to develop a method to synthesize discrete oligogermanes in good yields and to investigate the correlation between their structure and physical properties. We have developed a method to synthesize oligogermanes in good yields using the hydrogermolysis reaction and those compounds were characterized using 1H NMR, 13C NMR, 73Ge NMR, elemental analyses, UV/vis, CV and X-ray crystallography.Findings and Conclusions: We have developed a rational synthetic procedure for the synthesis of oligogermanes using a germanium amide and a germanium hydride. This reaction proceeds in the presence of acetonitrile via the formation of α-germyl nitrile, which is the active species of the reaction. Therefore, acetonitrile acts as a solvent as well as a reagent. Along with the hydrogermolysis reaction and the hydride protection/deprotection strategy, we have prepared a myriad of new compounds including both linear and branched oligomers. Using these combined methods, we can systematically change the number of germanium atoms in the molecule as well as the identity of the substituents. The optical properties and the electronic properties that we found correlate with the theoretically calculated values using DFT. Therefore, this synthetic methodology allows both "coarse-tuning" and "fine-tuning" of the properties of the molecule by varying the number of catenated germanium atoms and the identity of the organic substituents respectively.Chemistry Departmen

2,2,3,3,5,5,6,6-Octa-p-tolyl-1,4-dioxa-2,3,5,6-tetra­germacyclo­hexane dichloro­methane disolvate

The title compound, C56H56Ge4O2·2CH2Cl2 or Tol8Ge4O2·2CH2Cl2 (Tol = p-CH3C6H4), was obtained serendipitously during the attempted synthesis of a branched oligogermane from Tol3GeNMe2 and PhGeH3. The mol­ecule contains an inversion center in the middle of the Ge4O2 ring which is in a chair conformation. The Ge—Ge bond distance is 2.4418 (5) Å and the Ge—O bond distances are 1.790 (2) and 1.785 (2) Å. The torsion angles within the Ge4O2 ring are −56.7 (1) and 56.1 (1)° for the Ge—Ge—O—Ge angles and −43.9 (1)° for the O—Ge—Ge—O angle

Aryl Germanes as Ligands for transition Polymetallic Complexes: Synthesis, Structure, and Properties

A series of new carbonyl dichromium complexes bearing aryl germanes as ligands were prepared using improved approaches. The thermal reaction of Cr(CO)6 (1) with Me3GeGePh3 (3) led to the formation of Me3GeGePh[(η6‐C6H5)Cr(CO)3]2 (3a). The lithiation of [(η6‐C6H6)Cr(CO)3] (2) with nBuLi followed by the addition of Me2GeCl2 (4) or ClGeMe2GeMe2Cl (5) gave Me2Ge[(η6‐C6H5)Cr(CO)3]2 (4a) and [(OC)3Cr(η6‐C6H5)]GeMe2GeMe2[(η6‐C6H5)Cr(CO)3] (5a), respectively. The molecular structures of 3a and 4a, in their crystal forms, were studied by X‐ray diffraction analysis. The crystals of oligogermane 3a have shown to undergo a fully reversible phase transition at 160 K without any sign of decomposition. The complexes synthesized were also studied by multinuclear NMR, IR and UV/Vis spectroscopy, DFT calculations and electrochemistry. The presence of a Cr(CO)3 group in a range of oligogermanes has shown to impact on the physical and chemical properties of the compounds

Molecular oligogermanes and related compounds: Structure, optical and semiconductor properties

The optical (UV/Vis absorbance, fluorescence in the solid state and in solution) and semiconducting properties of a number of di- and trigermanes as well as related silicon- and tin-containing germanes, 1–6 ((p-Tol)3GeGeMe3 (1), Ph3SnGe(SiMe3)3 (2), (C6F5)3GeGePh3 (3), (p-Tol)3GeSiMe2SiMe3 (4), (p-Tol)3GeGeMe2Ge(p-Tol)3 (5), (p-Tol)3GeSiMe2SiMe2Ge(p-Tol)3 (6)) were investigated. Molecular structures of 5 and 6 were studied by X-ray diffraction analysis. All compounds displayed luminescence properties. In addition, a band gap (of about 3.3 eV) was measured for compounds 1–6 showing that those molecules display semiconductor properties