Alzheimer's disease is the most common form of age-related neurodegenerative dementia. The disease is characterised by the presence of plaques in the cerebral cortex. The major constituent of these ...plaques is aggregated amyloid-β peptide. This review focuses on the molecular aspects of metal complexes designed to bind to amyloid-β. The development of radioactive metal-based complexes of copper and technetium designed as diagnostic imaging agents to detect amyloid burden in the brain is discussed. Separate sections of the review discuss the use of luminescent metal complexes to act as non-conventional probes of amyloid formation and recent research into the use of metal complexes as inhibitors of amyloid formation and toxicity.
Non‐noble transition metal complexes have attracted growing interest as efficient electrocatalysts for oxygen reduction reaction (ORR) while their activities still lack rational and effective ...regulation. Herein, we propose a d–π conjugation strategy for rough and fine tuning of ORR activity of TM‐BTA (TM=Mn/Fe/Co/Ni/Cu, BTA=1,2,4,5‐benzenetetramine) coordination polymers. By first‐principle calculations, we elucidate that the strong d–π conjugation elevates the dxz/dyz orbitals of TM centers to enhance intermediate adsorption and strengthens the electronic modulation effect from substitute groups on ligands. Based on this strategy, Co‐TABQ (tetramino benzoquinone) is found to approach the top of ORR activity volcano. The synthesized Co‐TABQ with atomically distributed Co on carbon nanotubes exhibits a half‐wave potential of 0.85 V and a specific current of 127 mA mgmetal−1 at 0.8 V, outperforming the benchmark Pt/C. The high activity, low peroxide yield, and considerable durability of Co‐BTA and Co‐TABQ promise their application in oxygen electrocatalysis. This study provides mechanistic insight into the rational design of transition metal complex catalysts.
A two‐step strategy was proposed to optimize the ORR activity of TM‐BTA (TM=Mn/Fe/Co/Ni/Cu, BTA=1,2,4,5‐benzenetetramine) analogs by screening preliminarily TM centers and subsequently substituent groups. Strong d–π conjugation in TM‐BTA is found to elevate the dxz/dyz orbitals, which enhances the activity of TM centers, and also enlarges the impact of ligand functional groups on d orbitals of TM centers.
A novel, potassium orotate (OrK) and 1,3 di (4-pyridyl) propane (dpp) based, coordination network of Zn synthesized at room temperature. The emission spectrum of the Zn-complex recorded with 290 nm ...excitation wavelength reveals that complex has strong luminescence with the peak maximum 380 nm (3.2627 eV) and thermal stability of 1 upto 350 °C owing to different coordination environment around zinc atoms and crystal packing.
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•The syn-anti μ2η1:η1 bridging carboxylate and pyridyl extended the Or-Zn-dpp moiety into 2D coordination network showing square grid sheet.•The emission spectrum of Zn-complex was recorded with 290 nm excitation wavelength which reflects that 1 has strong luminescence with peak maximum of 380 nm (3.2627 eV).
A novel mixed ligand based coordination network of Zn, having formula Zn8(Or)8(dpp)4(H2O)8n (1), have been engineered and synthesized at room temperature by self-assembly of potassium orotate (OrK) and 1,3 di(4-pyridyl)propane (dpp) with metal salt, Zn(OAc)2·2H2O Single crystal X-ray structural analysis reveals that coordination sphere around Zn(II) ions, in Or-Zn-dpp moiety, having different atomic arrangement with distorted square pyramidal geometry. The syn-anti μ2η1:η1 bridging carboxylate and pyridyl moieties extended the Or-Zn-dpp skeleton into 2D coordination network showing square grid sheet. The emission spectrum of Zn-complex was recorded with 290 nm excitation wavelength which reflects that 1 has strong luminescence with peak maximum of 380 nm (3.2627 eV) and is a result of the n–π* and π–π* transitions of H3Or and dpp ligand. Thermogravimetric analysis shows that when the coordinated water molecule completely comes out from the complex around 320 °C, the dehydrated forms steadily starts to degrade, and the complete decomposition is observed above 350 °C.
Self-assembly of a flexible tritopic aniline and 3-substituted 2-formylpyridine subcomponents around iron(II) templates gave rise to a low-spin Fe
L
capsule, whereas a high-spin Fe
L
sandwich species ...formed when a sterically hindered 6-methyl-2-formylpyridine was used. The Fe
L
cage adopted a new structure type with S
symmetry, having two mer-Δ and two mer-Ʌ metal vertices, as confirmed by NMR and X-ray crystallographic analysis. The flexibility of the face-capping ligand endows the resulting Fe
L
framework with conformational plasticity, enabling it to adapt structurally from S
to T or C
symmetry upon guest binding. The cage also displayed negative allosteric cooperativity in simultaneously binding different guests within its cavity and at the apertures between its faces.
Although copper-ligand complexes appear to be promising as a new class of therapeutics, other than the family of copper(ii) coordination compounds referred to as casiopeínas these compounds have yet ...to reach the clinic for human use. The pharmaceutical challenges associated with developing copper-based therapeutics will be presented in this article along with a discussion of the potential for high-throughput chemistry, computer-aided drug design, and nanotechnology to address the development of this important class of drug candidates.
Pt
complexes are commonly used to treat cancer. To reduce their side effects and improve their pharmacological properties, Pt
complexes are being developed as prodrug candidates that are activated by ...reduction in cancer cells. Concomitantly, Ru
polypyridine complexes have gained much attention as photosensitizers for use in photodynamic therapy due to their attractive characteristics. In this article, a novel Pt
-Ru
conjugate, which combines cancer activated chemotherapy with PDT, is presented. Upon entering the cancer cell, the Pt
centre is reduced to Pt
and the axial ligands including the Ru
complex and phenylbutyrate are released. As each component has its individual targets, the conjugate exerts a multi-target and multi-action effect with (photo-)cytotoxicity values upon irradiation up to 595 nm in the low nanomolar range in various (drug resistant) 2D monolayer cancer cells and 3D multicellular tumour spheroids.
A bidentate chiral dithiol (diBINAS) is utilised to bridge Au
nanoclusters to form oligomers. Separation by size allows the isolation of fractions that are stable thanks to the bidentate nature of ...the linker. The structure of the products is elucidated by small-angle X-ray scattering and calculated using density functional theory. Additional structural details are studied by diffusion-ordered nuclear magnetic resonance spectroscopy, transmission electron microscopy and matrix-assisted laser desorption/ionization time of flight mass spectrometry. Significant changes in the optical properties are analysed by UV/Vis and fluorescence spectroscopies, with the latter demonstrating a strong emission enhancement. Furthermore, the emergent chiral characteristics are studied by circular dichroism. Due to the geometry constraints of the nanocluster assemblies, diBINAS can be regarded as a templating molecule, taking a step towards the directed self-assembly of metal clusters.
Cancer is one of the deadliest diseases worldwide. Recent statistics have shown that metastases and tumor relapse are the leading causes of cancer‐associated deaths. While traditional treatments are ...able to efficiently remove the primary tumor, secondary tumors remain poorly accessible. Capitalizing on this there is an urgent need for novel treatment modalities. Among the most promising approaches, increasing research interest has been devoted to immunogenic cell death inducing agents that are able to trigger localized cell death of the cancer cells as well as induce an immune response inside the whole organism. Preliminary studies have shown that immunogenic cell death inducing compounds could be able to overcome metastatic and relapsing tumors. Herein, the application of metal complexes as immunogenic cell death inducing compounds is systematically reviewed.
Metastases and tumor relapse are the leading causes of cancer‐associated deaths. Among other approaches, much research interest has been devoted to immunogenic cell death inducing agents that are able to trigger localized cell death of the cancer cells as well as induce an immune response inside the whole organism. Herein, the application of metal complexes as immunogenic cell death triggering compounds is systematically reviewed.
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