Anticancer and Antibiotic Rhenium Tri- and Dicarbonyl Complexes: Current Research and Future Perspectives

Organometallic compounds are increasingly recognized as promising anticancer and antibiotic drug candidates. Among the transition metal ions investigated for these purposes, rhenium occupies a special role. Its tri- and dicarbonyl complexes, in particular, attract continuous attention due to their relative ease of preparation, stability and unique photophysical and luminescent properties that allow the combination of diagnostic and therapeutic purposes, thereby permitting, e.g., molecules to be tracked within cells. In this review, we discuss the anticancer and antibiotic properties of rhenium tri- and dicarbonyl complexes described in the last seven years, mainly in terms of their structural variations and in vitro efficacy. Given the abundant literature available, the focus is initially directed on tricarbonyl complexes of rhenium. Dicarbonyl species of the metal ion, which are slowly gaining momentum, are discussed in the second part in terms of future perspective for the possible developments in the field.

Review—MoSe2 Nanostructures and Related Electrodes for Advanced Supercapacitor Developments

Molybdenum diselenide (MoSe2), an in-organic analog of graphene, is considered a rising star in the family of transition-metal dichalcogenides (TMDs) because of its stable covalent Mo–Se bond, good catalytic properties, huge specific surface area, higher electrical, multivalent oxidation states of transition metal ions, and its ability to be intercalated with suitably-sized metal atoms or organic molecules to modify their physical properties with a distinguishing layered structure. It is being projected as the next-generation 2D layered nano-material for many energy storage-conversion applications. This review covers the properties, functionalization of MoSe2, and their applications in supercapacitors, discussing the current developments of MoSe2 and its nano-composites-based supercapacitors, providing emphasis to the capacitive performances which comprise of specific capacitance/ capacity, cyclic lifespan, energy density, power density, rate capability, and their practicality in the real environments. Fundamental charge-storage mechanisms are also discussed to provide better insight into how MoSe2 is ascribed to each supercapacitor. Wherever applicable, limitations of the existing approaches and future outlook are also described.

Effects of Transition Metal Ions on the Colour of Blue-Green Beryl

This study reports the effects of transition metal ions on the colour of blue-green beryl. Industrial cameras were used to measure colour in the CIELAB colour space. X-ray fluorescence (XRF), X-ray diffraction (XRD), infrared spectroscopy (IR), and ultraviolet-visible (UV–vis) spectroscopy were used for characterization. The d–d transition of Fe3+ with sixfold coordination, the O2−→Fe3+ charge transfer, and the charge transition of binuclear metal M–M complexes formed by [Fe2(OH)4]2+ in the channel caused a yellow tone, whereas the charge transfer of Fe2+/Fe3+ with sixfold coordination caused a blue-green tone. The chroma of blue-green beryl was negatively correlated with the ratio of Cs+Mn to Fe contents. The lightness of blue-green beryl was negatively correlated with the total content of transition metal ions.

Coral-Like LaNixFe1-xO3 Perovskite Catalyst for High-Performance Oxygen Evolution Reaction

With the rare earth element La was selected as the A site and transition metal ions (Ni, Fe) as the B site of perovskite-type oxides with general formula ABO3, a series of LaNixFe1-xO3 (x=0, 0.3, 0.5, 0.7, 0.8, 1.0) perovskite catalysts were prepared by sol-gel method to investigate their catalytic performance for oxygen evolution reaction (OER). The catalyst activity was screened by linear scanning cyclic voltammetry (LSV), Tafel curves, and electrochemical impedance spectroscopy (EIS). A group of electrochemical tests for LaNixFe1-xO3 with various Ni/Fe ratios indicate that LaNi0.8Fe0.2O3 catalyst exhibits excellent electrochemical activity, with a resistance to charge-transfer reaction (Rct) of 5.942 Ω cm-2, overpotential of 391 mV, a Tafel slope of 102.8 mV dec-1, and electrochemical double-layer capacitance (Cdl) of 12.31 mF cm-1. The stability test after 15000 s proves that the optimized LaNi0.8Fe0.2O3 has better stability compared to pristine LaFeO3 and LaNiO3. In addition, LaNi0.8Fe0.2O3 also exhibits the largest electrochemical active area (ECSA=307.75 cm2) and exchange current density (jo=1.08 mA cm-2). This work provides reference for perovskite in improving oxygen evolution performance.

Coordination-assembled Nanoarchitectonics of Antioxidant Peptide and Flavonoid Myricetin for Sustainably Scavenging Free Radicals

Oxidative stress can lead to permanent and irreversible damage for cellular components, and even cause cancer and many diseases. Therefore, the development of antioxidative reagents is a significant strategy for alleviating chronic diseases and maintaining the redox balance. Small-molecule bioactive compounds have exhibited huge therapeutic potential in antioxidant and anti-inflammatory. Myricetin (Myr) as well-defined natural flavonoid, has drawn wide attention on highly effective antioxidant, anti-inflammatory, antimicrobial, and anticancer activities. Especially at antioxidation, Myr is capable of not only chelating intracellular transition metal ions for removing reactive oxygen species (ROS), but also activating antioxidant enzymes and related signal, achieving sustainable scavenging radical activity. However, Myr possesses poor water solubility, which limits its bioavailability for biomedical application, even clinical therapeutic potential. The endogenous antioxidant peptide glutathione (GSH) plays a direct role on antioxidant in cells and possesses good hydrophilicity and biocompatibility, but is easily metabolized by enzyme. To take advantages of their antioxidation activity and overcome the above-mentioned limitations, the GSH, Zn2+ and Myr are selected to co-assemble into Myr-Zn2+-GSH (abbreviated as MZG nanoparticles or nanoarchitectonics). Thence, this study offers a new design to harness stable, sustainable antioxidant nanoparticles with high loading capacity and bioavailability, good biocompatibility for optimizing antioxidant to protect cells from oxygenated damage.