Selenium containing macrocycles: transformation between Se–N/Se–S/Se–Se bonds

Ebselen-Agents for Sensing, Imaging and Labeling: Facile and Full-Featured Application in Biochemical Analysis

Phenyl-1,2-benzoselenazol-3(2H)-one (ebselen) is a classical mimic of glutathione peroxidase (GPx). Thioredoxin interaction endows ebselen attractive biological functions, such as antioxidation and anti-infection, as well as versatile therapeutic usage. Accordingly, application of ebselen analogues in biosensing, chemical labeling, imaging analysis, disease pathology, drug development, clinical treatment, etc. have been widely developed, in which mercaptans, reactive oxygen species, reactive sulfur species, peptides, and proteins were involved. Herein, focusing on the application of ebselen-agents in biochemistry, we have made a systematic summary and comprehensive review. First, we summarized both the classical and the innovative methods for preparing ebselen-agents to present the synthetic strategies. Then we discussed the full functional applicability of ebselen analogues in three fields of biochemical analysis including the fluorescence sensing and bioimaging, derivatization for high throughput fluorescence analysis, and the labeling gents for proteomics. Finally, we discussed the current challenges and perspectives for ebselen-agents as analytical tools in biological research. By presenting the multifunctional applicability of ebselen, we hope this review could appeal researchers to design the ebselen-related biomaterials for biochemical analysis.

Effect of Molecular Structure in the Chain Mobility of Dichalcogenide-Based Polymers with Self-Healing Capacity

Recently, it has been shown that the reaction mechanism in self-healing diphenyl dichalcogenide-based polymers involves the formation of sulfenyl and selenyl radicals. These radicals are able to attack a neighbouring dichalcogenide bond via a three-membered transition state, leading to the interchange of chalcogen atoms. Hence, the chain mobility is crucial for the exchange reaction to take place. In this work, molecular dynamics simulations have been performed in a set of disulfide- and diselenide-based materials to analyze the effect of the molecular structure in the chain mobility. First of all, a validation of the computational protocol has been carried out, and different simulation parameters like initial guess, length of the molecular chains, size of the simulation box and simulation time, have been evaluated. This protocol has been used to study the chain mobility and also the self-healing capacity, which depends on the probability to generate radicals ( ρ ), the barrier of the exchange reaction ( Δ G ) and the mobility of the chains ( ω ). The first two parameters have been obtained in previous quantum chemical calculations on the systems under study in this work. After analyzing the self-healing capacity, it is concluded that aromatic diselenides (PD-SeSe) are the best candidates among those studied to show self-healing, due to lower reaction barriers and larger ω values.

Diselenide Bonds as an Alternative to Outperform the Efficiency of Disulfides in Self-Healing Materials

Self-healing materials are a very promising kind of materials due to their capacity to repair themselves. Among others, dichalcogenide-based materials are widely studied due to their dynamic covalent bond nature. Recently, the reaction mechanism occurring in these materials was characterized both theoretically and experimentally. In this vein, a theoretical protocol was established in order to predict further improvements. Among these improvements, the use of diselenides instead of disulfides appears to be one of the paths to enhance these properties. Nevertheless, the physicochemical aspects of these improvements are not completely clear. In this work, the self-healing properties of several disulfides, diselenides, and mixed S-Se materials have been considered by means of computational simulations. Among all the tested species, diphenyl diselenide based materials appear to be the most promising ones due to the decrease on the reaction barriers, instead of weaker diselenide bonds, as thought up to now. Moreover, the radical formation needed in this process would also be enhanced by the fact that these species are able to absorb visible light. In this manner, at room conditions, selenyl radicals would be formed by both thermal dissociation and photodissociation. This fact, together with the lower energetic barriers needed for the diselenide exchange, makes diphenyl diselenides ideal for self-healing materials.

Surface Modification Based on Diselenide Dynamic Chemistry: Towards Liquid Motion and Surface Bioconjugation

Surface modification is an important technique in fields, such as, self-cleaning, surface patterning, sensing, and detection. The diselenide bond was shown to be a dynamic covalent bond that can undergo a diselenide metathesis reaction simply under visible light irradiation. Herein we develop this diselenide dynamic chemistry into a versatile surface modification method with a fast response and reversibility. The diselenide bond could be modified onto various substrates, such as, PDMS, quartz, and ITO conductive film glass. Different functional diselenide molecules could then be immobilized onto the surface via diselenide metathesis reaction. We demonstrated that by using this modification method we could achieve liquid motion in a capillary tube under light illumination. We also show that this approach has the potential to serve as an efficient modification method for surface bioconjugation, which has practical applications in clinical usage.