A novel test device and quantitative colorimetric method for the detection of human chorionic gonadotropin (hCG) based on Au@Zn-salen MOF for POCT applications

The human chorionic gonadotropin (hCG) hormone is a biomarker that can predict tumors and early pregnancy; however, it is challenging to develop sensitive qualitative-quantitative procedures that are also effective, inventive, and unique. In this study, we used a novel easy in situ reaction of an organic nano-linker with Zn(NO₃)₂·6H₂O and HAuCl₄·3H₂O to produce a gold-zinc-salen metal-organic framework composite known as Au-Zn-Sln-MOF. A wide variety of micro-analytical instruments and spectroscopic techniques were used in order to characterize the newly synthesized Au-Zn-Sln-MOF composite. Disclosure is provided for a novel swab test instrument and a straightforward colorimetric approach for detecting hCG hormone based on an Au-Zn-Sln-MOF composite. Both of these methods are easy. In order to validate a natural enzyme-free immunoassay, an Au-Zn-Sln-MOF composite was utilized in the role of an enzyme; a woman can use this gadget to determine whether or not she is pregnant in the early stages of the pregnancy or whether or not her hCG levels are excessively high, which is a symptom that she may have a tumor. This cotton swab test device is compatible with testing of various biological fluids, such as serum, plasma, or urine, and it can be easily transferred to the market to commercialize it as a costless kit, which will be 20-30% cheaper than what is available on the market. Additionally, it can be used easily at home and for near-patient testing (applications of point-of-care testing (POCT)).

A Novel Insight into the Ullmann Homocoupling Reactions Performed in Heterogeneous Catalytic Systems

The Ullmann reaction has been reported to be the first cross-coupling reaction performed by using a transition metal catalyst. This reaction has been initially considered as the copper-catalyzed homocoupling of aryl halides, leading to the formation of symmetrical biaryl compounds via the generation of novel C-C bonds. Although this reaction has been extensively studied in recent decades and valuable results have been achieved, there are still considerable efforts focused on the development of novel catalytic systems, mild reaction conditions, and extended substrate scope. The mechanistic aspects of the Ullmann homocoupling reaction have also been investigated, as related to the introduction of new sustainable strategies and green procedures. The application of recyclable heterogeneous catalysts has been found to overcome most of the limitations associated with the harsh reaction conditions of the original Ullmann reaction. More recently, copper-based catalytic systems have also been replaced by palladium nanoparticles, ionic palladium species, gold nanoparticles, and palladium-gold bimetallic systems. In this review, current results reported on the Ullmann homocoupling reaction are discussed, with an emphasis on the development of novel catalytic systems, which can be efficiently used under heterogeneous conditions.

On the Roles of Electron Transfer in Catalysis by Nanoclusters and Nanoparticles

Electron transfer plays a major role in chemical reactions and processes, and this is particularly true of catalysis by nanomaterials. The advent of metal nanoparticle (NP) catalysts, recently including atomically precise nanoclusters (NCs) as parts of nanocatalyst devices has brought increased control of the relationship between NP and NC structures and their catalytic functions. Consequently, the molecular definition of these new nanocatalysts has allowed a better understanding and management of various kinds of electron transfer involved in the catalytic processes. This Minireview brings a chemist's view of several major aspects of electron-transfer functions concerning NPs and NCs in catalytic processes. Particular focus concerns the role of NPs and NCs as electron reservoirs and light-induced antenna in catalytic processes from H₂ generation to more complex reactions and sustainable energy production.

Recent Advances in the Synthesis of 2,2′-Bipyridines and Their Derivatives

The sustained interest in the synthesis of new analogues of 2,2′-bipyridines is supported by the importance of compounds featuring bipyridine core in diverse areas of chemical, biomedical and materials research, which is relayed into the development of new approaches and the expansion of existing synthetic methods. This short review covers advances in the synthesis of 2,2′-bipyridines, including both the synthesis of compounds with a given substitution pattern and the development of new methods for assembling the bipyridine core. Special attention is directed toward the use of pyridine N-oxides and metal-free protocols to facilitate the formation of bipyridines. This short review focuses primarily on reports published in the last 5–6 years.

1 Introduction

2 Ullmann-Type Homocoupling Reactions

3 Cross-Coupling Reactions in the Synthesis of Bipyridines

4 Coupling Reactions Employing Pyridine N-Oxides

5 Other Methods for the Synthesis of 2,2′-Bipyridines

6 Conclusions and Outlook

N,N-Dimethylformamide-Protected Single-Sized Metal Nanoparticles and Their Use as Catalysts for Organic Transformations

In this mini-review, we summarize the solution syntheses of N,N-dimethylformamide (DMF)-protected metal nanoparticles (NPs) and nanoclusters (NCs) and their use in catalytic reactions. Representative examples are given of external-stabilizer/protectant-free metal NP and NC syntheses by reduction with DMF. In this method, DMF has three roles, i.e., a solvent, reductant, and protectant. Recent applications of DMF-stabilized metal NPs are summarized. These applications have enabled a versatile organic transformation such as cross-coupling reactions, hydrosilylation, and methylation to be achieved. These reactions proceed under low catalyst loadings and ligandless conditions.

ZIF-8-based vs. ZIF-8-derived Au and Pd nanoparticles as efficient catalysts for the Ullmann homocoupling reaction

On comparing ZIF-8-based and ZIF-8-derived gold and palladium nanocatalysts, they were found to be very efficient for the optimized Ullmann coupling of iodoarenes in DMF.

Shape-controlled synthesis of Ni nanocrystals via a wet-chemistry strategy and their shape-dependent catalytic activity

We have synthesized Ni nanocrystals with different shapes via a facile wet-chemistry strategy, and investigated their shape-dependent performances.

Surfactant-assisted assembly of nanoscale zinc coordination compounds to enhance tandem conversion reactions in water

Nanoscale 1 and 2 with the benefit of readily accessible active sites had shown to be more effective heterogeneous catalysts than large sizes of 1 and 2 to execute tandem conversion reactions of nitromethylbenzenes into benzolic acids frameworks.

Beyond a solvent: triple roles of dimethylformamide in organic chemistry

N,N-Dimethylformamide (DMF) is frequently used as an aprotic solvent in chemical transformations in laboratories of academia as well as in those of chemical industry. In the present review, we will reveal that DMF is actually something much more than a solvent. It is a unique chemical since, as well as being an effective polar aprotic solvent, it can play three other important roles in organic chemistry. It can be used as a reagent, a catalyst, and a stabilizer.

Enhanced Electrocatalytic Activity of Ethanol Oxidation Reaction on Palladium-Silver Nanoparticles via Removable Surface Ligands

This work developed a facile colloidal route to synthesize BH₄^--capped Pd_xAg_y nanoparticles (NPs) in water using the reducing ionic liquids of [C_nmim]BH₄, and the resulting NPs were prone to form the nanocomposites with [amim]⁺-modified reduced graphene (RG). The removal of the metal-free inorganic ions of BH₄^- can create the profoundly exposed interfaces on the Pd_xAg_y NPs during the electrooxidation, and favor the ethanol oxidation reaction (EOR) in lowering energy barrier. The counterions of [C_nmim]⁺ can gather ethanol, OH^- ions, and the reaction intermediates on catalysts, and synergistically interact with RG to facilitate the charge transfer in nanocomposites. The interface-modified RG nanosheets can effectively segregate the Pd_xAg_y NPs from aggregation during the EOR. Along with the small size of 4.7 nm, the high alloying degree of 60.2%, the large electrochemical active surface area of 64.1 m² g^-1, and the great peak current density of 1501 mA cm^-2 mg^-1, Pd₁Ag₂@[C₂mim]BH₄-amimRG nanocomposite exhibits the low oxidation potentials, strong poison resistance, and stable catalytic activity for EOR in alkaline media, and hence can be employed as a promising anodic catalyst in ethanol fuel cells.

Thiols make for better catalysts: Au nanoparticles supported on functional SBA-15 for catalysis of Ullmann-type homocouplings

A strategy for arraying nanoparticles (NPs) on mesoporous supports modified with functional self-assembled monolayers is described. Au NPs supported on materials containing thiols exhibited thermal stability and catalytic competency well beyond that of unsupported, thiol-protected Au NPs of similar size.