Synthesis Of Arrays Research Articles

Circularly Polarized Antenna Array Synthesis Based on Machine-Learning-Assisted Surrogate Modeling

Circularly Polarized Antenna Array Synthesis Based on Machine-Learning-Assisted Surrogate Modeling

Theoretical and numerical simulation to control the wideband three-dimensional interfering noise by the broadband constant beam pattern method for a spherical array

The broadband constant beam pattern (CBP) spherical array synthesis theory is applied to suppress or to cancel wideband three-dimensional interfering noise sources by implanting zeros in the array's original synthesized shading function. This modified array angular shading function can be expanded by a series of spherical harmonics that will converge to the beam pattern in the far-field such that the created nulls are in the wideband interfering noise source directions per the CBP theory where the ratio of the spherical array radius to the operating frequency wavelength is large. The simulated numerical examples given for this wideband noise source suppression method demonstrate that a broadband CBP performance is maintained for the spherical array with a Legendre polynomial shading function, the classic Dolph–Chebyshev shading function, or a combination. With the CBP design, one set of the real shading functions works for all frequencies in the array's operating band to cancel or to suppress three-dimensional wideband interfering noise sources.

Sparse Array Synthesis with Two-Stage Progressive BCS and Undirected Graph-Based Spacing Constraint

Sparse Array Synthesis with Two-Stage Progressive BCS and Undirected Graph-Based Spacing Constraint

Catalytic enantioselective reductive Eschenmoser-Claisen rearrangements.

An important challenge in enantioselective catalysis is developing strategies for the precise synthesis of neighboring congested all-carbon quaternary stereocenters. The well-defined transition states of [3,3]-sigmatropic rearrangements and their underlying stereospecificity render them powerful tools for the synthesis of such arrays. However, this type of pericyclic reaction remains notoriously difficult to catalyze, especially in an enantioselective fashion. Herein, we describe an enantioselective reductive Eschenmoser-Claisen rearrangement catalyzed by chiral 1,3,2-diazaphospholene-hydrides. This developed transformation enables full control of the two newly formed acyclic stereogenic centers, leading to amides with vicinal all-carbon quaternary-tertiary or quaternary-quaternary carbon atoms.

Facile synthesis and modification of Fe2O3 nanorod arrays on carbon paper as efficient negative electrodes for supercapacitors

In this research, Fe2O3 nanorod arrays grown on carbon fiber paper were studied, and carbon-coated Fe2O3 (Fe2O3 @C) and sulfurized Fe2O3 @C (Fe2O3 @C-S) were fabricated by carbon coating and sulfurization processes. To promote the application of these materials in supercapacitors, their electrochemical properties were systematically investigated. Based on the results, the materials obtained utilized a pseudocapacitive mechanism for energy storage. Specifically, Fe2O3 exhibited a moderate specific capacitance and extraordinary cycling stability, and no degradation was observed after 10,000 cycles. Impressively, sulfurization greatly enhanced the rate capability and specific capacitance of the sample. As a result, Fe2O3 @C-S attained a specific capacitance of 976.4 mF cm–2 at 4 mA cm–2 and a robust rate capability of 97.30% at 20 mA cm–2, outperforming Fe2O3 @C (84.39%) and Fe2O3 (70.55%) and demonstrating good cycling stability (92.9%). Notably, Fe2O3 @C-S was active as a positive electrode material; thus, a symmetric supercapacitor was assembled, which yielded a volumetric energy density of 1.46 mWh cm–3 at 16.71 mW cm–3 and maintained an energy density of 0.91 mWh cm–3 even at 145.63 mW cm–3. Moreover, the device exhibited good cycling stability with a capacity retention of 88.3% after 10,000 cycles at 10 mA cm–2. The integration of Fe2O3 nanorod arrays on conductive substrates, coupled with the above modifications, strongly promoted the material’s energy storage performance. Our study emphasized the significant potential of Fe2O3 @C-S as an efficient electrode material for supercapacitors.

Efficient synthesis of novel thiadiazolo[2,3-b]quinazolin-6-ones catalyzed by diphenhydramine hydrochloride-CoCl2⋅6H2O deep eutectic solvent

In this research, a new Lewis acid-based deep eutectic solvent (LA-DES) was synthesized using diphenhydramine hydrochloride and CoCl2·6H2O, (2[HDPH]:CoCl42−), and identified by FT-IR and 1HNMR techniques. The physicochemical properties of this LA-DES, such as thermal behavior, thermal stability, and solubility in common solvents were also investigated. The catalytic ability of 2[HDPH]:CoCl42− was ascertained in the efficient synthesis of a novel array of thiadiazolo[2,3-b]quinazolin-6-one scaffolds via a one-pot three-component reaction of dimedone/1,3-cyclohexanedione, aldehydes, and 5-aryl-1,3,4-thiadiazol-2-amines/3-(5-amino-1,3,4-thiadiazol-2-yl)-2H-chromen-2-one under solvent-free conditions. This catalyst was also successfully utilized for the synthesis of mono- and bis-thiadiazolo[2,3-b]quinazolin-6-ones from dialdehydes or bis-1,3,4-thiadiazol-2-amine. The simplicity of enforcement, short reaction time, avoidance of toxic organic solvents, scalability of the synthesis procedure, excellent atom economy, high reaction mass efficiency, and low E-factor are other outstanding advantages of this newly developed method. Furthermore, due to the convenient recovery and reuse of LA-DES, this protocol is economically justified and environmentally friendly.

One-dimensional single atom arrays on ferroelectric nanosheets for enhanced CO2 photoreduction

Single-atom catalysts show excellent catalytic performance because of their coordination environments and electronic configurations. However, controllable regulation of single-atom permutations still faces challenges. Herein, we demonstrate that a polarization electric field regulates single atom permutations and forms periodic one-dimensional Au single-atom arrays on ferroelectric Bi4Ti3O12 nanosheets. The Au single-atom arrays greatly lower the Gibbs free energy for CO2 conversion via Au-O=C=O-Au dual-site adsorption compared to that for Au-O=C=O single-site adsorption on Au isolated single atoms. Additionally, the Au single-atom arrays suppress the depolarization of Bi4Ti3O12, so it maintains a stronger driving force for separation and transfer of photogenerated charges. Thus, Bi4Ti3O12 with Au single-atom arrays exhibit an efficient CO production rate of 34.15 µmol·g−1·h−1, ∼18 times higher than that of pristine Bi4Ti3O12. More importantly, the polarization electric field proves to be a general tactic for the syntheses of one-dimensional Pt, Ag, Fe, Co and Ni single-atom arrays on the Bi4Ti3O12 surface.

Facile Microwave-Assisted Hydrothermal Synthesis of Copper Oxide Nanoneedle Arrays for Practical Biomedical Applications.

Copper oxide nanoneedle arrays (CuO NAs) have been widely used as antibacterial agents and in therapeutic applications because of their unique physicochemical features, low cytotoxicity, low cost, exceptional antibacterial action, and significant interest in biomedicine. Various analytical techniques were used to assess the related phase constitution, optical characteristics, elemental content, and surface morphology. The X-ray diffraction (XRD) patterns and field-emission scanning electron microscopy (FE-SEM) micrographs revealed that the CuO NAs had a monoclinic phase with a nanoneedle-like shape. Our findings may cover the progress of innovative and effective anti-bacterial capabilities based on CuO NAs, which have been shown to be effective against various pathogens, making them ideal options for fighting bacterial infections. Objective: This research aimed to synthesize CuO NAs using microwave-solvothermal (MW-ST) technology, explore their effectiveness, and assess their biological activity. The CuO NAs were synthesized using the MW-ST process, and their properties were assessed using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), field emission scanning electron microscopy (FE-SEM), energy dispersive analysis (EDS), field emission transmission microscopy (FE-TEM), and ultraviolet-visible (UV-Vis) techniques. The biocompatibility of CuO NAs was determined through hemolytic assays, and their bioactivities like antioxidant and anti-inflammatory assays were also determined. The CuO NAs were successfully developed,and various analytical tools were used to characterize and validate their morphology, size, crystallinity, and elemental compositions. It has been shown in in-vitro investigations that a strong anti-inflammatory impact is demonstrated by the inhibition of protein denaturation with low hemolytic potential. As a result, CuO NAs have the potential to be an excellent choice for anti-inflammatory solicitations. CuO NAs were synthesized and characterized with various advanced techniques, revealing the formation of nanoneedles-like morphology. Based on the experimental findings, CuO NAs have the potential for anti-microbial, anti-oxidant, anti-inflammatory, and anti-hemolytic activities. However, additional in-vivo testing is essential to properly evaluate their efficiency and safety.

Accessing Borazine Substitution Patterns through Late‐Stage Iodination

AbstractWe have defined a procedure for the late‐stage functionalization of aryl borazines to facilitate the synthesis of a diverse array of borazine derivatives with varying substitution patterns, paving the way for further exploration of the field. More in detail, we have studied and disclosed a simple iodination procedure that could be applied to several differently substituted substrates (1 a–i) with mostly good to excellent yields (47–96%). The representative iodinated compounds 2 b and 2 e, were utilized to test their use in further representative functionalization steps such as cyanation, Heck, and Sonogashira reactions. All products 3 a–e were obtained in satisfactory good to very good yields considering the multiple (three or six times) concomitant reactions.

Correction: Synthesis of TiC nanotube arrays and their excellent supercapacitor performance

Correction for ‘Synthesis of TiC nanotube arrays and their excellent supercapacitor performance’ by Tongxiang Ma et al., J. Mater. Chem. A, 2022, 10, 9932–9940, https://doi.org/10.1039/D2TA00957A.

Visible-light-driven asymmetric aldol reaction of ketones and glycinates via synergistic Lewis acid/photoredox catalysis.

Visible-light-driven direct asymmetric α-C(sp3)-H bond functionalization of glycinate provides a direct and efficient route for the synthesis of diverse optically enriched α-amino acid derivatives. However, asymmetric coupling between glycinate radical species and ketones faces significant challenges, including competitive pathways, mutable intermediates, as well as congested stereogenic centers. Herein, we disclose the first example for the asymmetric photocatalytic synthesis of a diverse array of β-diaryl-β-hydroxy-α-amino acetate derivatives from glycinates and heteroaryl ketones through the synergistic catalysis of achiral iridium photoredox catalyst and chiral lanthanide Lewis acid catalysts. The enantioselective radical addition pathway is supported by spectroscopic experiments, control experiments and DFT calculations.

Efficient and Accurate Pattern Synthesis of Circular Antenna Array Employing Iterative Fast Segmented Cyclic Convolution

Efficient and Accurate Pattern Synthesis of Circular Antenna Array Employing Iterative Fast Segmented Cyclic Convolution

Synthesis of phase-only thinned concentric elliptical antenna arrays based on the topology optimization continuous 0–1 differentiation

Synthesis of phase-only thinned concentric elliptical antenna arrays based on the topology optimization continuous 0–1 differentiation

Multiple-cycle photochemical cascade reactions.

Cascade reactions represent an efficient and economical synthetic approach, enabling the rapid synthesis of a wide array of structurally complex organic compounds. These compounds, previously inaccessible, can now be synthesized in a remarkably limited number of steps. Concurrently, the photochemical reactions of organic molecules have gained prominence as a potent strategy for accessing a diverse range of radical species and intermediates. This is achieved in a controlled manner under mild conditions. Owing to the relentless endeavors of chemists, significant strides have been made in the realm of photochemical cascade reactions. These advancements have facilitated the synthesis of novel molecular structures with high complexity, structures that are typically challenging to generate under thermal conditions. In this review, we comprehensively summarize and underscore the recent pivotal advancements in visible-light-induced cascade reactions. Our focus is on the elucidation of multiple photochemical catalytic cycles, emphasizing the catalytic activation modes and the types of reactions involved.

Electrochemical synthesis of phosphorylated azaspiro[4.5]di/trienones through dearomative spirocyclization.

Cp2Fe-mediated electrochemical synthesis of a diverse array of phosphorylated azaspiro[4.5]di/trienones has been developed, which demonstrated broad substrate scope and good diastereoselectivity. It represents the first example of electrochemical synthesis of phosphorylated azaspiro[4.5]di/trienones, circumventing the need for external oxidants and high temperatures. Moreover, a plausible mechanism including radical-initiated dearomative cyclization driven by ferrocenium cations has been provided, which was supported by the related mechanistic study.

Templated Synthesis of CsPbBr3 Nanowire Arrays Toward Low Current Drift and Stable X-ray Detector

All-inorganic halide perovskite CsPbBr3 with superior environmental stability, remarkable radiation hardness and great defect tolerance has emerged as a competitive material in radiation detection. However, the operation stability of CsPbBr3...

Exploring the synthetic potential of dihydroxyacetone-aldolases from acidophilic organisms

Two novel dihydroxyacetone-aldolases showcase unique characteristics, distinguishing them from the E. coli counterpart. They enable efficient synthesis of a diverse array of known monosaccharides along with novel compounds previously inaccessible.

Au]/[Ag]-catalysed synthesis of non-hydrolysable C-glycosides.

Many C-glycosides are found in natural products, drugs and small molecular probes. Herein, we report the synthesis of C-glycosides by the [Au]/[Ag]-catalysed activation of ethynylcyclohexyl glycosyl carbonate donors. This mild, catalytic, fast and high yielding protocol enables the synthesis of a diverse array of C-glycosides that were otherwise challenging to synthesize.

Recent advances in spirocyclization of maleimides via transition-metal catalyzed C-H activation.

In recent years, the maleimide scaffold has received a great deal of attention in C-H activation. Several types of products can be constructed using maleimides as a coupling partner. Alkylation, alkenylation, annulation, dehydrogenative annulation and spirocyclization are various reactions shown by maleimides in C-H activation. Thus, the maleimide scaffold has been extensively studied in the last few years in C-H activation owing to its unique reactivity. Among the diverse class of reactions of maleimides, spirocyclization is a less explored reaction. The spirocycles, in particular the spirosuccinimides are interesting candidates in drug discovery and materials chemistry. Therefore the method of spirocyclization of maleimides via C-H activation becomes an important strategy for the synthesis of a diverse array of spirosuccinimides. This review summarizes the reports available in this field from 2015-2023 and also highlights the scopes and prospects of this method.

Wide-Angle Scanning Thinned Phased Array Synthesis Based on Improved Multi-Objective Beluga Whale Optimization Algorithm

Wide-Angle Scanning Thinned Phased Array Synthesis Based on Improved Multi-Objective Beluga Whale Optimization Algorithm