Triboluminescence Phenomenon Based on the Metal Complex Compounds-A Short Review

Triboluminescence (TL) is a phenomenon of light emission resulting from the mechanical force applied to a substance. Although TL has been observed for many ages, the radiation mechanism is still under investigation. One of the exemplary compounds which possesses triboluminescent properties are copper(I) thiocyanate bipyridine triphenylphosphine complex [Cu(NCS)(py)₂(PPh₃)], europium tetrakis dibenzoylmethide triethylammonium EuD₄TEA, tris(bipyridine)ruthenium(II) chloride [Ru(bpy)₃]Cl₂, and bis(triphenylphosphine oxide)manganese(II) bromide Mn(Ph₃PO)₂Br₂. Due to the effortless synthesis route and distinct photo- and triboluminescent properties, these compounds may be useful model substances for the research on the triboluminescence mechanism. The advance of TL studies may lead to the development of a new group of sensors based on force-responsive (mechanical stimuli) materials. This review constitutes a comprehensive theoretical study containing available information about the coordination of metal complex synthesis methodologies with their physical, chemical, and spectroscopic properties.

Review on the hazardous applications and photodegradation mechanisms of chlorophenols over different photocatalysts

Chlorophenols are very important environmental pollutants, which have created huge problems for both aquatic and terrestrial lives. Therefore, their removal needs urgent, effective, and advanced technologies to safeguard our environment for future generation. This review encompasses a comprehensive study of the applications of chlorophenols, their hazardous effects and photocatalytic degradation under light illumination. The effect of various factors such as pH and presence of different anions on the photocatalytic oxidation of chlorophenols have been elaborated comprehensively. The production of different oxidizing agents taking part in the photodegradation of chlorophenols are given a bird eye view. The photocatalytic degradation mechanism of different chlorophenols over various photocatalyts has been discussed in more detail and elaborated that how different photocatalysts degrade the same chlorophenols with the aid of different oxidizing agents produced during photocatalysis. Finally, a future perspective has been given to deal with the effective removal of these hazardous pollutants from the environment.

Recent advances of SBA-15-based composites as the heterogeneous catalysts in water decontamination: A mini-review

As an emerging class of silica-based mesoporous materials with incorporation of active components (e.g., transition metals/metal oxides and nanocarbons), SBA-15-based composites (X@SBA-15) have been attracting increasing attention in the field of water treatment owing to their unique characteristics and excellent remediation performance. This paper reviews recent advances in catalytic applications of X@SBA-15 to remove organic contaminants from water. Emphasis is made on the use of X@SBA-15 in four advanced oxidation processes (AOPs) (i.e., photocatalysis, Fenton-like oxidation, catalytic ozonation, and sulfate radical-based oxidation). Impregnation and hydrothermal methods are two most widely used synthetic approaches to combine the active composites with SBA-15, obtaining a synergistic effect with significant improvement in their individual catalytic activity for pollution remediation. The enhanced generation of highly reactive hydroxyl radicals from the surface of X@SBA-15 was widely recognized as being responsible for water decontamination using these AOPs, while sulfate radicals were also involved during activation of persulfate or peroxymonosulfate. Especially, X@SBA-15 could significantly enhance the light harvest and reduce the recombination of photo-induced electrons and holes during photocatalytic treatment, which also played the critical role in oxidizing the organics. The superior catalytic performance of X@SBA-15 without leaching metal ions during successive runs demonstrated the excellent reusability and structural stability. Together with the reduced toxicity of the treated solutions and the cost-effective characteristics of X@SBA-15 nanohybrids reported in the published literature, their great potential as the efficient and environmentally friendly heterogeneous catalysts in a real use scenario is suggested. Finally, the future perspectives on the development and practical utilization of X@SBA-15 are addressed.

Synthesis of Stilbene and Chalcone Inhibitors of Influenza A Virus by SBA-15 Supported Hoveyda-Grubbs Metathesis

Stilbene and chalcone derivatives with biological activity against influenza A virus have been synthesized by self-, cross-, and ring-closing metathesis procedures. The reactions were performed under environmentally friendly conditions using the second generation Hoveyda-Grubbs catalyst Aquamet SiPr after immobilization on Santa Barbara Amorphous mesoporous silicate SBA-15. Irrespective from the experimental conditions, the heterogeneous catalyst showed activity and selectivity comparable than the homogeneous counterpart for at least six successive runs without appreciable leaching of the active species. An appreciable antiviral activity against influenza A virus for some of the novel derivatives were observed, mainly involving the early stage of the virus-replication life-cycle.

Sonochemically-Promoted Preparation of Silica-Anchored Cyclodextrin Derivatives for Efficient Copper Catalysis

Silica-supported metallic species have emerged as valuable green-chemistry catalysts because their high efficiency enables a wide range of applications, even at industrial scales. As a consequence, the preparation of these systems needs to be finely controlled in order to achieve the desired activity. The present work presents a detailed investigation of an ultrasound-promoted synthetic protocol for the grafting of β-cyclodextrin (β-CD) onto silica. Truly, ultrasound irradiation has emerged as a fast technique for promoting efficient derivatization of a silica surface with organic moieties at low temperature. Three different β-CD silica-grafted derivatives have been obtained, and the ability of β-CD to direct and bind Cu when CD is bonded to silica has been studied. A detailed characterization has been performed using TGA, phenolphthalein titration, FT-IR, diffuse reflectance (DR), DR UV-Vis, as well as the inductively-coupled plasma (ICP) of the β-CD silica-grafted systems and the relative Cu-supported catalysts. Spectroscopic characterization monitored the different steps of the reaction, highlighting qualitative differences in the properties of amino-derivatized precursors and final products. In order to ensure that the Cu-β-CD silica catalyst is efficient and robust, its applicability in Cu(II)-catalyzed alkyne azide reactions in the absence of a reducing agent has been explored. The presence of β-CD and an amino spacer has been shown to be crucial for the reactivity of Cu(II), when supported.