What a chemistry student should know about the history of Prussian blue

Heat-Resistant Carbon-Coated Potassium Magnesium Hexacyanoferrate Nanoplates for High-Performance Potassium-Ion Batteries

Metal hexacyanoferrates (HCFs) are regarded as promising cathode materials for potassium-ion batteries (PIBs) on account of their low cost and high energy density. However, the difficult-to-remove [Fe(CN)6] vacancies and crystal water lead to structural instability and capacity deterioration as well as the stereotype of poor thermostability of conventional HCFs. Herein, we report (100) face-oriented potassium magnesium hexacyanoferrate (KMgHCF) nanoplates with low [Fe(CN)6] vacancies and high crystallinity, enabling thermostability up to 550 °C, high-temperature carbon coating and crystal water elimination. The as-obtained KMgHCF/C nanoplates exhibit superior potassium storage properties, including a large reversible capacity of 84.6 mAh g-1, a high voltage plateau of 3.87 V, excellent long-term cycling performance over 15000 cycles and high rate capability at 5 A g-1. The unprecedented cycling stability of KMgHCF/C is attributed to the synergistic effect of a highly reversible two-phase reaction, low [Fe(CN)6] vacancies and no crystal water, a specially exposed steady (100) surface, and a protective carbon coating. This work provides a new material selection and modification strategy for the practical application of HCFs in PIBs.

Decorporation dilemma: Interplay of prussian blue and potassium iodide in radioactive contamination

The expansion of the nuclear industry has led to various radioactive effluents, originating from routine operations or catastrophic incidents such as those at Three Mile Island (USA), Chernobyl (Ukraine), and Fukushima (Japan). Research conducted after these events emphasizes Cesium-137 (137Cs) and iodine 131 (131I) as major contributors to harmful airborne dispersion and fallout. These isotopes infiltrate the human body via inhalation, ingestion, or wounds, posing significant health risks. Understanding contamination mechanisms and devising effective countermeasures are crucial in mitigating nuclear incident consequences. We propose that concurrent administration of Pru-Decorp™/Pru-Decorp-MG and potassium iodide (KI) could synergistically reduce the levels of 137Cs and block uptake of 131I, respectively, in nuclear incident scenarios. Pru-Decorp™ capsules contain insoluble ferric hexacyanoferrate(II) and are equivalent to USFDA-approved Radiogardase®-Cs, offering radiation exposure mitigation for Cs and Tl contamination. Pru-Decorp-MG capsules consist of insoluble PB and magnesium hydroxide, serving as a prophylactic measure to reduce the risk of internal Cs and Tl contamination for rescue responders. Pru-Decorp™/Pru-Decorp-MG binds Cs/Tl ions in the gastrointestinal tract, hindering absorption and promoting excretion, while KI saturates the thyroid gland with stable iodine, decreasing the uptake of radioactive iodine isotopes. Our hypothesis is supported by studies demonstrating the effectiveness of combination therapies, such as calcium alginate, iron(III) ferrocyanide, and KI, in decreasing the retention of radioisotopes in vital organs. To test this hypothesis, we propose a comprehensive research plan, including in vitro studies simulating gastrointestinal conditions, animal studies to evaluate the efficacy of both drugs simultaneously, and safety clinical trials comparing Pru-Decorp™/Pru-Decorp-MG alone, KI alone, and their combination. Expected outcomes include insights into the synergistic effects of Pru-Decorp™/Pru-Decorp-MG and KI, guiding the development of optimized treatment protocols for simultaneous administration during radioactive contamination incidents. This research aims to address significant critical gaps in nuclear incident preparedness by providing evidence-based recommendations for concurrent antidote use in scenarios involving multiple isotope contamination. Ultimately, this will enhance public health and safety during nuclear emergencies.

The role of oxidative stress in intervertebral disc degeneration: Mechanisms and therapeutic implications

Oxidative stress is one of the main driving mechanisms of intervertebral disc degeneration(IDD). Oxidative stress has been associated with inflammation in the intervertebral disc, cellular senescence, autophagy, and epigenetics of intervertebral disc cells. It and the above pathological mechanisms are closely linked through the common hub reactive oxygen species(ROS), and promote each other in the process of disc degeneration and promote the development of the disease. This reveals the important role of oxidative stress in the process of IDD, and the importance and great potential of IDD therapy targeting oxidative stress. The efficacy of traditional therapy is unstable or cannot be maintained. In recent years, due to the rise of materials science, many bioactive functional materials have been applied in the treatment of IDD, and through the combination with traditional drugs, satisfactory efficacy has been achieved. At present, the research review of antioxidant bioactive materials in the treatment of IDD is not complete. Based on the existing studies, the mechanism of oxidative stress in IDD and the common antioxidant therapy were summarized in this paper, and the strategies based on emerging bioactive materials were reviewed.

Exploring Electrochemistry: A Hydrogen Peroxide Sensor Based on a Screen-Printed Carbon Electrode Modified with Prussian Blue

There is an increasing need for fundamental electrochemistry concepts to be taught in the undergraduate curriculum, given the broad applicability of electrochemical technologies in addressing a wide range of global issues from critical energy shortages to real-time medical diagnostics. However, many electrochemical concepts are often taught in disparate laboratory experiments, spread out through the curriculum, which can be intimidating to students (and instructors). This experiment, which has been tested and optimized in the undergraduate classroom over multiple semesters, covers a wide range of electrochemistry topics in realizing the construction of a hydrogen peroxide (H2O2) sensor that is based on Prussian blue electrochemistry. The experiment introduces the fundamentals of cyclic voltammetry by prompting students to distinguish faradaic and capacitive components of voltammograms and to investigate their relationship with scan rate as per electrochemical theory. Students also evaluate electrocatalysis through electrodeposition of a thin film of Prussian blue on the sensor surface and the effects of this modification on electron transfer and sensor performance. Finally, students combine amperometric measurements with the method of standard additions to determine H2O2 concentrations in an unknown sample. Overall, this experiment offers an integrated and cohesive experience that connects many important electroanalytical concepts that are often taught individually into one 3 h, hands-on laboratory experiment that requires minimal resources.

Investigations of Nanoparticle Suspensions of Prussian Blue and Its Copper Analogue: Amine Functionalization and Electrochemical Studies

Prussian blue (PB) and its analogues are promising materials for electrochemical energy storage, yet their use in flow-type devices is limited by their lack of redox responsiveness as colloidal suspensions. We have investigated the redox chemistry amine functionalization of PB along with its Cu analogue (CuPBA). No redox response of colloidal PB was observed and suspensions of CuPBA formed films on electrode surfaces with and without applied potentials; the films were redox-active but the material that remained suspended in solution did not participate in redox chemistry. Propylamine (pa), ethylenediamine (en), or tetramethylethylenediamine (TMEDA) were added in an attempt to maintain well dispersed suspensions through nanoparticle surface functionalization. Propylamine modifications resulted in a loss of the CuPBA network and subsequent precipitation of insoluble materials. Coordination of ethylenediamine prompted the formation of Cu and Fe monomers ([Cu(en)₂]^m+/[Fe(CN)₆]^n-]) that remained soluble in aqueous electrolytes. In the absence of supporting electrolytes, these monomers formed a one-dimensional (1D) polymeric structure (Cu₂Fe-1D). TMEDA modification preserved the CuPBA extended structure with only modest precipitate formation over 30 min. The redox responsiveness of these suspensions depended on conditions; in 1 M KCl, no redox chemistry was observed for the CuPBA. In pH 4 potassium hydrogen phthalate buffer, a signal was observed that was attributed to the Fe centers of CuPBA. Under these conditions, the material precipitated in ∼15 min and the signal was lost. Although the Fe centers in these networks are redox-active, additional work is needed to realize longer-term redox activity and stability. Ligand modifications can alter the properties of these networks but within a given ligand class, e.g., amines, the effects can vary greatly from the deconstruction of the framework to preventing film formation.

The world of inorganic pigments

Abstract

Inorganic pigments have been very important substances for human life for thousands of years. They have contributed and continue to contribute to the beautification of our daily life and habitat and to the accentuation and differentiation of objects, and influence thoughts, moods, and feelings. The industrial manufacture of inorganic pigments based on growing chemical and physical knowledge started around 1800. Before that, pigments based on natural materials or manufactured by mostly empirical processes were used. Most of the technically relevant inorganic pigments were developed and first produced on an industrial scale in the nineteenth and twentieth centuries. Ongoing developments are aiming to improve existing conventional pigments as well as synthesize new, innovative colorants, especially in the classes of effect pigments and functional pigments. The objective of this text is to present comprehensive knowledge about inorganic pigments, including definitions, types of pigments and their properties, historical pigments, modern inorganic pigments, synthesis methods, and applications. It is also intended to show the current status of new pigment developments.

Graphical abstract

Collection of samples of inorganic pigments

Anticancer, Antibacterial, Antioxidant, and DNA-Binding Study of Metal-Phenalenyl Complexes

Phenalenyl (PLY)-based metal complexes are a new addition to the metal complex family. Various applications of metal-based phenalenyl complexes (metal-PLY) have been reported, such as catalyst, quantum spin simulators, spin electronic devices, and molecular conductors, but the biological significance of metal-PLY (metal = Co(II), Mn(III), Ni(II), Fe(III), and Al(III)) systems has yet to be explored. In this study, the anticancer properties of such complexes were investigated in ovarian cancer cells (SKOV3 and HEY A8), and the cytotoxicity was comparable to that of other platinum-based drugs. Antibacterial activity of the metal-PLY complexes against both gram-negative (E. coli) and gram-positive (S. aureus) bacteria was studied using a disk diffusion test and minimum inhibitory concentration (MIC) methods. All five metal-PLY complexes showed significant antibacterial activity against both bacterial strains. The antioxidant properties of metal-PLY complexes were evaluated following the 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging method and were acceptable. The DNA-binding properties of these metal-PLY complexes were investigated using absorption spectroscopy, fluorescence spectroscopy, viscosity measurements, and thermal denaturation methods. Experimental evidence revealed that the complexes bind to DNA through intercalation, and the molecular docking study supported this conclusion.

Prussian Blue Analogues for Sodium-Ion Batteries: Past, Present, and Future

Prussian blue analogues (PBAs) have attracted wide attention for their application in the energy storage and conversion field due to their low cost, facile synthesis, and appreciable electrochemical performance. At the present stage, most research on PBAs is focused on their material-level optimization, whereas their properties in practical battery systems are seldom considered. This review aims to first provide an overview of the history and parameters of PBA materials and analyze the fundamental principles toward rational design of PBAs, and then evaluate the prospects and challenges for PBAs for practical sodium-ion batteries, hoping to bridge the gap between laboratory research and commercial reality.

Spot tests: past and present

Microchemistry, i.e., the chemistry performed at the scale of a microgram or less, has its roots in the late eighteenth and early nineteenth centuries. In the first half of the twentieth century a wide range of spot tests have been developed. For didactic reasons, they are still part of the curriculum of chemistry students. However, they are even highly important for applied analyses in conservation of cultural heritage, food science, forensic science, clinical and pharmacological sciences, geochemistry, and environmental sciences. Modern pregnancy tests, virus tests, etc. are the most recent examples of sophisticated spot tests. The present ChemTexts contribution aims to provide an overview of the past and present of this analytical methodology.

Recent advances in solid-contact ion-selective electrodes: functional materials, transduction mechanisms, and development trends

This article presents a comprehensive overview of recent progress in the design and applications of solid-contact ion-selective electrodes (SC-ISEs).