Monthly Archives: January 2024

Amino‐Acid Side‐Chain Nanoarchitectonics for Tuning the Chiroptical Properties and Supramolecular Structure of Pentameric Oligothiophenes

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Amino-Acid Side-Chain Nanoarchitectonics for Tuning the Chiroptical Properties and Supramolecular Structure of Pentameric Oligothiophenes

Self-assembled Proteophenes. Oligothiophenes with distinct amino acid side-chain functionalities along the conjugated backbone displayed distinct chiroptical and structural properties in acidic or alkaline solutions. The distinct photophysical characteristics, as well as the supramolecular structures of the assemblies were highly influenced by the chemical nature of the amino acid, as well as the positioning of distinct amino acid moieties along the thiophene backbone.


Abstract

Oligothiophenes with specific photophysical properties and molecular organization are of great interest, since this class of materials are used in organic electronics and bioelectronics, as well as biosensing. Herein, 8 different pentameric oligothiophenes, denoted proteophenes, with different amino acid substitution patterns at distinct positions along the thiophene backbone were investigated. Spectroscopic and microscopic studies of the ligands revealed the formation of optically active self-assembled materials under acidic or basic conditions. The distinct photophysical characteristics, including induced circular dichroism, as well as the supramolecular structures of the assemblies deduced from light scattering and transmission electron microscopy, were highly influenced by the positioning of distinct amino acid moieties along the thiophene backbone. Proteophenes functionalized with only glutamate residues or these functionalities in combination with hydrophobic valine moieties formed fibrillar structures with excellent chiroptical properties under acidic conditions. In addition, the amino acid functionality at the β-position of distinct thiophene moieties influenced the induced circular dichroism pattern observed from the proteophenes. Overall, the obtained results demonstrate how changes in the position of various amino acid functionalities, as well as the chemical nature of the amino acid side chain functionality greatly affect the optical properties as well as the architecture of the self-assembled materials.

D‐A* Co‐polymerization Realizing Chiral Thermally Activated Delayed Fluorescent Polymers for Highly Efficient Circularly Polarized Polymer Light‐emitting Diodes

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D-A* Co-polymerization Realizing Chiral Thermally Activated Delayed Fluorescent Polymers for Highly Efficient Circularly Polarized Polymer Light-emitting Diodes

A pair of chiral TADF-active polymer emitters were designed and synthesized by the spiro donor-chiral acceptor strategy, and intense CPEL signals were detected from the corresponding CP-PLED devices.


Abstract

Circularly polarized electroluminescence (CPEL) from polymers with thermally activated delayed fluorescence (TADF) properties has been rapidly developed in recent years. So far, the designing strategies of such chiral TADF-active polymers are still limited. In this work, a new strategy of D−A* co-polymerization was proposed and two chiral polymers R-pSACODP and S-pSACODP were synthesized. The circularly polarized polymer light-emitting diode (CP-PLED) devices fabricated with R-pSACODP and S-pSACODP achieved comparable performances with maximum external quantum efficiencies (EQEs) of 12.0 % and 11.7 % at the wavelength of 581 nm, respectively. Moreover, mirror-imaged CPEL signals were also detected with electroluminescence dissymmetry factors (g EL) of −1.1×10−3 and +1.3×10−3 from the corresponding CP-PLED devices, respectively. The results in this work effectively extend the designing strategies for the achievement of CPEL from chiral TADF-active polymers.

Utilization of Nickel ferrite (NiFe2O4) in Hematite (α‐Fe2O3) Photoanode for Photoelectrochemical Water Splitting as a Blocking Layer

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Utilization of Nickel ferrite (NiFe2O4) in Hematite (α-Fe2O3) Photoanode for Photoelectrochemical Water Splitting as a Blocking Layer

The introduction of the NiFe2O4 layer into the hematite results in a reduction in the onset potential, signifying an enhancement in the performance of PEC water splitting. This shift is attributed to the inhibition of electron back transfer from the FTO substrate to the hematite film.


Abstract

We found a new blocking layer (nickel ferrite, NiFe2O4), that could be utilized for the suppression of the back recombination, occurring in the hematite (α-Fe2O3) photoanode. The photoanode in which the NiFe2O4 layer was introduced showed a cathodic shift of the onset potential in the current density versus applied voltage curve. We successfully demonstrated that the NiFe2O4 layer effectively inhibited the back recombination in the hematite film through the use of electrochemical and time-resolved spectroscopic methods.

Synthesis and Properties of Ag‐Au Alloy Nanoparticles with Controlled Composition for Computed Tomography Imaging Applications

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Synthesis and Properties of Ag-Au Alloy Nanoparticles with Controlled Composition for Computed Tomography Imaging Applications

In this study, Ag−Au alloy NPs were synthesized successfully in an organic solvent. The quantity of HAuCl4.3H2O influenced the morphology and properties of the alloy materials. The Ag−Au solutions after phase transfer using poly (maleic anhydride-alt-1-octadecene) reached high durability, stability and non-toxic to the Vero healthy cell line. In-vitro CT images indicated a good X-ray absorption coefficient. Our findings expanded the potential uses of Ag−Au alloy NPs in biomedicine, particularly for imaging diagnosis employing CT imaging technology.


Abstract

Numerous non-invasive assays have been developed to support CT imaging, consequently increasing the precision of diagnosis. Although these efforts made a significant contribution to clinical research, there is still more to be done. The goal is to replace conventional contrast agents with more potent ones. In this study, Ag−Au alloy nanoparticles were fabricated by substitution method between the precursor Au3+ and the previously prepared Ag nanoparticles. Effects of Au3+ quantity on the formation and characteristics of Ag−Au alloy nanoparticles were investigated. It showed that Ag−Au nanoalloy with a size of 14.2±1.0 nm, SPR absorption peak at 520 nm, and Ag: Au atomic ratio of approximately 3 : 1 were appropriate for biomedical applications. After phase transfer using poly (maleic anhydride-alt-1-octadecene) (PMAO), the nano Ag−Au solution owned remarkable durability, stability and non-toxicity Vero healthy cell line at high test concentration. In-vitro CT imaging demonstrated a good X-ray adsorption coefficient, and the hounsfield units (HU) was noticeably increased. As a promising CT contrast agent, the X-ray attenuation of nano Ag−Au solutions correlated linearly with concentrations. These findings led to a potential application in the biomedical field, particularly in computed tomography (CT) imaging diagnosis.

Main Group Analogs of Dichalcogeniranes

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Main Group Analogs of Dichalcogeniranes

We briefly summarized the recent advances in the preparation of main group analogs of dioxirane, dithiirane, diselenirane and ditellurirane stable in the solid state. The unique structures were characterized by X-ray diffraction analysis. Dechalcogenation of thus obtained main group dichalcogeniranes afforded the corresponding double-bonded compounds. Other reactivity and outlook are also described.


Abstract

This Mini Review highlights recent advances in the preparation of main group analogs of dichalcogeniranes. The three–membered ring compounds are an intriguing class of compounds in terms of their strained structures and high reactivity. As for three–membered rings composed of a carbon and two group 16 atoms, dioxiranes have long been utilized as oxidants, while some dithiiranes have been synthesized. In contrast, diselenirane and ditellurirane remain elusive. On the other hand, the chemistry of three–membered rings consisting of a non–carbon main group atom and two group 16 atoms has recently gained significant track. These emerging three–membered ring compounds were characterized by X-ray diffraction analysis on many occasions, revealing unique molecular structures with very long chalcogen–chalcogen single–bond distances in some cases. A common reactivity is dechalcogenation reactions using phosphine reagents, which provide access to the corresponding double-bonded compounds. This minireview covers recent advances in the synthesis of main group analogs of dioxirane, dithiirane, diselenirane, and even ditellurirane.

Biosynthesis of ZnO, Bi2O3 and ZnO−Bi2O3 bimetallic nanoparticles and their cytotoxic and antibacterial effects

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Biosynthesis of ZnO, Bi2O3 and ZnO−Bi2O3 bimetallic nanoparticles and their cytotoxic and antibacterial effects

In this work, attempted to arrange synthesized Bi2O3, ZnO, ZnO−Bi2O3 nanoparticles by Biebersteinia Multifida extract and then their cytotoxicity and anti-bacterial investigate. This is a report on the synthesis and anticancer performance of synthesized samples on breast cancer cells (MCF-7), as well as their anti-bacterial activity against Staphylococcus epidermidis and Pseudomonas aeruginosa bacteria.


Abstract

This work introduces an easy method for producing Bi2O3, ZnO, ZnO-Bi2O3 nanoparticles (NPs) by Biebersteinia Multifida extract. Our products have been characterized through the outcomes which recorded with using powder X-ray diffractometry (PXRD), Raman, energy dispersive X-ray (EDX), field emission-scanning electron microscopy (FE-SEM), and Fourier-transform infrared (FT-IR) techniques. The finding of SEM presented porous structure and spherical morphology for Bi2O3 and ZnO NPs, respectively. While FE-SEM image of bimetallic nanoparticles showed both porous and spherical morphologies for them; so that spherical particles of ZnO have sat on the porous structure of Bi2O3 NPs. According to the PXRD results, the crystallite sizes of Bi2O3, ZnO and ZnO−Bi2O3 NPs have been obtained 57.69, 21.93, and 43.42 nm, respectively. Antibacterial performance of NPs has been studied on Staphylococcus epidermidis and Pseudomonas aeruginosa bacteria, to distinguish the minimum microbial inhibitory concentration (MIC). Antimicrobial outcomes have showed a better effect for ZnO-Bi2O3 NPs. Besides, wondering about the cytotoxic action against cancer cell lines, the MTT results have verified the intense cytotoxic function versus breast cancer cells (MCF-7). According to these observations, obtained products can prosper medical and biological applications.

Reactivity of an Iron Carbonyl Dianion Dictated by a Lewis Basic Appendant

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Reactivity of an Iron Carbonyl Dianion Dictated by a Lewis Basic Appendant

Reactions of an Fe(-II) carbonyl dianion bearing an amino appendant with diverse electrophiles generated a range of unprecedented products, most notably a diphenylstannylene complex formed via chelate-assisted oxidative addition of Sn−Ph bond. The amino appendant is proposed to play a pivotal role in differentiating the reactivity of this dianion to the basic [Fe(CO)4]2− species.


Abstract

Studies toward transition metals in negative oxidation states are much less explored compared to those in zero or positive oxidation states. In this study, we present the synthesis and reactivity studies of an Fe(-II) carbonyl dianion (3) featuring an appended Lewis base, [(L)Fe(CO)3]2− (L=Ph2PCH2CH2NMe2). Unlike the well-known reactivity of [Fe(CO)4]2− with common electrophiles (E +) which typically forms [(E)2Fe(CO)4], 3 reacted with 2 equiv. of Ph3SnCl to afford a mixture of two products: one being an Fe(II) bis(triphenylstannyl) product (4), and the other an Fe stannylene product (5). Further insights into the reactivity of 3 was elucidated through its reactions with 2 equiv. of Cy3SnCl or Me3SiCl, producing an Fe(II) bis(tricyclohexylstannyl) product (8) and a zwitterionic complex (11), respectively, the latter emerging via THF ring-opening. Intermediates generated from reactions of 3 with 1 equiv. of each electrophile were isolated to shed light on the reaction mechanisms, highlighting the influence of appended Lewis base on the reactivity of metal carbonyl dianions, especially the generation of the novel stannylene complex 5. The electronic structure of this paramagnetic stannylene complex was also investigated by computational studies.