Search Results (88)

Herein, a novel insensitive diazonium inner salt of 2-nitro-5-oxo[1,2,4]triazolo[1,5-c]pyrimidin-8-diazonium-7-olate (NTPD) was synthesized through a concise three-step route. The structure and performance of this material were comprehensively studied. Single-crystal X-ray diffraction analysis revealed that NTPD possesses a distinctive fused-ring framework featuring an inner salt (zwitterionic) structure, wherein the diazonium and phenolate functionalities are intramolecularly integrated within a compact, highly conjugated heterocyclic system. Furthermore, in comparison with previously reported diazonium compounds, NTPD exhibits a superior combination of enhanced thermal stability and significantly reduced mechanical sensitivity. Specifically, its onset decomposition temperature reaches 206 °C, representing a substantial improvement over conventional diazo derivatives, while its impact sensitivity of 7 J positions it among the least sensitive diazonium-based energetic materials reported to date. The exceptional performance of NTPD is strongly attributed to its nearly planar molecular geometry and the extensive hydrogen-bonding network present within its crystal lattice, which collectively reinforce structural rigidity, enhance packing stability, and effectively dissipate external mechanical stimuli. Full article

The Pschorr reaction is a radical-mediated intramolecular cyclization involving diazonium salts, affording five-, six- and seven-membered fused polycyclic and heterocyclic rings, discovered by R. Pschorr in the late nineteenth century. Over the years, this classic reaction has played an important role in ring-forming reactions. In 2009 we reviewed the progress in the field. The intervening years have witnessed major advances in the application of Pschorr reaction that are mediated by various metals, by photocatalysis, and by ionic liquids, leading to the development of new and improved methods for the synthesis of diverse bioactive heterocycles. The notable progress in the field since our 2009 review provided the impetus to summarize, discuss, and put these advances in perspective. Full article

Disruption of the intestinal barrier is a hallmark of inflammatory bowel disease (IBD) and drives both epithelial injury and neutrophil-mediated inflammation, yet rapid, multiplexed assessment of these processes remains an unmet clinical need. Intestinal fatty acid binding protein (iFABP) and fecal calprotectin (FC) provide complementary insights into barrier integrity and mucosal inflammation, but conventional ELISA-based assays are time-consuming, low-throughput, and require large sample volumes. Here, we introduce a dual electrochemical sandwich immunosensor enabling simultaneous quantification of iFABP and FC on screen-printed dual carbon electrodes (SPdCEs). Capture antibodies were immobilized via electrografting of p-aminobenzoic acid diazonium salt, while a V₂O₅/MWCNTs-HRP–streptavidin nanocomposite amplified the electrocatalytic reduction in hydrogen peroxide, enhancing sensitivity. The platform achieved detection limits of 0.01 pg mL⁻¹ (iFABP) and 1 pg mL⁻¹ (FC) with a total assay time of 1 h 20 min and sample volume of just 5 μL, outperforming conventional ELISA in speed and efficiency. High repeatability, reproducibility, and accurate recovery in enriched fecal samples confirmed analytical robustness. By integrating multiplexed detection, nanostructured signal amplification, and robust electrode engineering, this immunosensor provides a rapid, sensitive, and low-volume platform for point-of-care and decentralized monitoring of IBD, enabling timely clinical decision-making and longitudinal patient management. Full article

Cannabis use is generally restricted worldwide because it contains the narcotic compound Δ⁹-tetrahydrocannabinol (Δ⁹-THC). Although cannabis is detected at crime scenes using color-based primary screening methods, the details of the reaction mechanism have not yet been elucidated. In this study, we isolated the products generated during the color reaction between the diazonium salt prepared from para-nitroaniline and nine cannabinoids and determined their structures. Azo compounds 6, 11, 16, and 17 were produced from cannabidiol, cannabigerol, cannabichromene, and cannabidiolic acid, respectively, while quinoneimines 7–10 and 12–15, which contained positional isomers, were produced from cannabinol, Δ⁹-THC, and hexahydrocannabinol. The reaction barely proceeded with Δ⁹-THC acetate and HHC acetate. Full article

Background: 8-Quinolinol and its derivatives are drawing significant attention across various disciplines due to their remarkable versatility. These compounds are well-known for their exceptional chelating ability, forming stable metal complexes via their nitrogen and oxygen electron donor atoms. This main characteristic determines their broad utility. Biological activity can also be explained by the chelating capacity, which allows 8-quinolinol to bind to essential metal ions such as Fe, Zn, Cu, and others. This chelation disrupts metal-dependent biological processes in target cells or organisms, leading to a range of effects, including antimicrobial, anticancer, antifungal, and neuroprotective activities. On the other hand, the biological activity of pyrazole derivatives is attributed to their heterocyclic structure, which allows for interactions with biological targets that can lead to enzyme inhibition, receptor antagonism, radical scavenging, and other effects. Objective: This work aimed to synthesize and characterize novel diazene compounds derived from 8-quinolinol or 2-methyl-8-quinolinol and pyrazole amines, and to evaluate their antimicrobial and anticancer activities. Methods: The compounds have been synthesized by coupling diazonium salts obtained from the diazotization of heterocyclic amines with 8-quinolinol and its derivative, 2-methyl-8-quinolinol. The careful selection of reaction conditions enabled the synthesis of high-purity products. The compounds were characterized by 1D and 2D NMR, FT-IR spectroscopy, UV-Vis spectroscopy, and LC-HRMS analysis. The biological activity of the newly synthesized compounds was evaluated following the protocols of EU-OPENSCREEN, a European Research Infrastructure Consortium (ERIC) initiative dedicated to supporting early drug discovery. Results: By combining diazonium salts obtained from 3-methyl-1H-pyrazol-5-amine and ethyl 5-amino-3-methyl-1H-pyrazole-4-carboxylate with the aforementioned coupling agents, four novel 8-quinolinol derivatives were synthesized. The further hydrolysis of the ethoxy carbonyl functional group allowed its conversion to a carboxylic functional group, thus expanding the series of new compounds to six members. Several compounds from the series have proven to be biologically active against several human pathogenic microorganisms and the Hep-G2 cancer cell line. Conclusions: The combination of two well-known biologically active scaffolds through a classic diazo coupling reaction allowed the synthesis of novel biologically active compounds, which showed promising results as possible antifungal and anticancer agents. These results represent a foundation for future studies, which will include a broader biological screening and in vivo studies. Full article

A first application of 2-(methoxycarbonyl)thiophen-3-diazonium salts in the halothienylation of α,β-unsaturated functionalized compounds under Meerwein reaction conditions is presented. This process provides thiophene-containing building blocks that can then undergo cyclization reactions with bisnucleophiles to synthesize thiophene-3-yl-containing heterocyclic systems. In this way, substituted 2,3′-bithiophene compounds and thiophene-3-yl derivatives of 2-aminothiazole, 2-aminoselenazole, thiazolidine, and selenazolidine can be efficiently prepared. Full article

Although cannabis is used in a wide range of fields, including medicine and pharmacology, its use is prohibited in Japan because it contains Δ⁹-tetrahydrocannabinol (Δ⁹-THC), a compound that exhibits narcotic effects. While cannabis is primarily detected via color-based screening methods at crime scenes, the reaction products and mechanisms associated with these screening methods have not been fully elucidated. To address this issue, the colored products were isolated via the diazo-coupling reactions of the major cannabinoids (cannabidiol, cannabinol, and Δ⁹-THC) in cannabis with the Fast Blue RR diazonium salt, and their structures were determined using NMR spectroscopy. As expected, azo compound 2 was formed from cannabidiol, whereas cannabinol and Δ⁹-THC produced quinoneimines 3 and 4, respectively. This study is expected to lead to the future development of more sensitive color-based reagents that produce fewer false positives. Full article

Aryl diazonium salt chemistry offers a robust and versatile approach for the modification of material surfaces via the covalent immobilization of reactive functional groups under mild conditions. In this study, this strategy was successfully applied to graft the chelating agent 4-(2-pyridylazo)resorcinol (PAR) onto Amberlite XAD-4 resin. Initially, 4-nitrobenzenediazonium tetrafluoroborate (NBDT) was covalently anchored onto the resin surface using hypophosphorous acid as a reducing catalyst to introduce aryl nitro groups. These nitro groups were subsequently reduced to aniline functionalities, enabling diazo coupling with PAR. The successful modification of the resin was confirmed by ATR-FTIR spectroscopy, thermogravimetric analysis (TGA), and X-ray photoelectron spectroscopy (XPS). The synthesized chelating resin exhibited sorption capacities of 0.152, 0.167, and 0.172 mM g⁻¹ for Co(II), Ni(II), and Cu(II), respectively. The functionalized resin was packed into standard SPE cartridges and employed as a selective sorbent for the extraction and preconcentration of trace metals from groundwater samples collected from Dhalamah Valley, Al-Madinah Al-Munawwarah, prior to quantification by inductively coupled plasma mass spectrometry (ICP-MS). These results demonstrate the effectiveness of rapid diazonium-based surface functionalization for the preparation of selective polymeric metal chelators suitable for the extraction of trace metals from complex groundwater matrices. Full article

Designing a highly sensitive and efficient functionalized electrode for precise drug analysis remains a significant challenge. In this work, an electrochemical sensor based on a glassy carbon electrode (GCE) modified with phenyl diazonium salts (ph) and electrochemically reduced graphene oxide (ERGO), labeled GCE/ph/ERGO, was developed for the detection of paracetamol (PAR) in pharmaceutical matrices using square wave voltammetry (SWV). The modified electrode was characterized by scanning electron microscopy (SEM), electrochemical impedance spectroscopy (EIS), and cyclic voltammetry (CV). Compared to the bare GCE, the GCE/ph/ERGO sensor demonstrated significantly improved conductivity and anodic current peak for PAR over two orders of magnitude higher, indicating a substantial enhancement in electrochemical performance. Under optimized conditions, the developed sensor exhibited a low detection limit of 18.2 nM and a quantification limit of 60.6 nM. Precision studies yielded relative standard deviations (RSDs) below 8%. The sensor demonstrated excellent selectivity in the presence of common pharmaceutical excipients and high accuracy in the analysis of generic pharmaceutical formulations, with results comparable to those obtained by the HPLC technique. These findings confirm the sensor’s reliability, stability, robustness, and suitability for routine analysis of PAR in pharmaceutical samples. Full article

Background/Objectives: This study aims to evaluate the possible clinical application of interleukin 8 (IL-8) as a single biomarker and its capabilities in combination with carbohydrate antigen (CA19-9), carcinoembryonic antigen (CEA), and carcinoembryonic antigen cell adhesion molecule 6 (CEACAM6) as diagnostic and prognostic tools for pancreatic ductal adenocarcinoma (PDAC). Methods: A total of 170 serum samples from patients with PDAC (n = 100), chronic pancreatitis (CP) (n = 39), and healthy individuals (n = 31) were analysed. IL-8 and CEACAM6 were measured by an enzyme-linked immunosorbent assay (ELISA). CA19-9 and CEA were determined by chemiluminescent microparticle immunoassay, and bilirubin was quantified using a diazonium salt reaction. Receiver operating characteristic curve analysis, logistic regression, and Kaplan–Meier analyses were performed to evaluate the properties of a single IL-8 and in combination with other biomarkers. Results: The concentrations of IL-8 were statistically significantly higher in the PDAC group compared to the CP and control groups. Heterogeneous levels of IL-8 correlated with PDAC stages (p = 0.007). IL-8 had good and satisfactory diagnostic efficacy in differentiating PDAC from controls (0.858; p < 0.001) and patients with CP (0.696; p < 0.001), respectively. High and low expressions of IL-8 were not significantly associated with overall survival (OS) or disease-free survival (DFS). A combination of IL-8, CEACAM6, and CA19-9 reached the highest AUC values for differentiating PDAC from the control group. The best classification score between PDAC and the control group with CP patients was obtained by merging IL-8 and CA19-9 (0.894; p < 0.001). Conclusions: These results provide compelling evidence of IL-8 as a promising diagnostic biomarker. Nonetheless, due to the high complexity of PDAC, only the conjunction of IL-8, CA19-9, and CEACAM6 integrates sufficient diagnostic capabilities. Full article

Measuring pH with an optical sensor requires the immobilization of a chemical recognition phase on a solid surface. Neutral red (NR), an acid base indicator was used to develop two different optical probe configurations. The chemistry of aryl diazonium salts was chosen for the elaboration of this chemical phase, as it enables strong covalent bonds to be established on the surface of metallized glass or metallic surfaces. It also allows the formation of a thick film required to obtain an exploitable spectral response. The surfaces of interest (metallized optical fiber and 316 L stainless-steel mirror) are modelized by flat surfaces (metallized glass plates and 316 L stainless-steel plates). The analytical characterizations carried out (IR, XPS, UV-Visible, and profilometry) show that NR was covalently grafted onto the model surfaces as well as on the surfaces of interest. The supports grafted with NR to develop optical pH probes exhibit spectral changes, particularly the values of pKa, the pH range, and the isosbestic point wavelength. The experimental results show that the optical probe can be used for pH measurements between 4 and 8. Full article

The interfacial properties between carbon fiber (CF) and thermoplastic resin are relatively weak, which can be problematic for composites in structural applications. Improving the surface roughness of CF is regarded as an effective way to enhance the interface of composites. However, most CF modifying methods are complex and time-consuming, which cannot meet the demand for industrial production. Therefore, it is of great significance to research a fast technique of CF surface modification to strengthen the interface of composites. Herein, a one-pot reaction based on the aryl diazonium salt modification was applied to enhance the interface between CF and poly ether ether ketone (PEEK) resin. Carbon nanotubes (CNTs) were linked to CF by p-phenylenediamine (PPD) via cyclic voltammetry (CV). The surface morphology, chemical characteristics and surface energy of modified CF illustrated the effectiveness of this method, and the interfacial properties of as-prepared modified CF/PEEK demonstrated the increased tendency. All the CF was treated within 5 min and the interfacial shear strength (IFSS) of CF/PEEK was increased to the maximum of 99.62 MPa by aryl diazonium salt modification. This work may shed some light on the industrialized application of CF reinforced high-performance engineering thermoplastic composites. Full article

1-(3-aryl)-3-(dimethylamino)prop-2-en-1-one (enaminones) derivatives and the diazonium salt of para-chloroaniline were used to synthesize several novel disperse azo dyes with high yield and the use of an environmentally friendly approach. At 100 and 130 °C, we dyed polyester fabrics using the new synthesized disperse dyes. At various temperatures, the dyed fabrics’ color intensity was assessed. The results we obtained showed that dyeing utilizing a high temperature method at 130 °C was enhanced than dyeing utilizing a low temperature method at 100 °C. Reusing dye baths once or twice was a way to achieve two goals at the same time. The first was obtaining a dyed product at no cost, and the second was a way to treat the wastewater of dyeing bath effluents and reuse it again. Good results were obtained for the fastness characteristics of polyester dyed with disperse dyes. When the disperse dyes were tested against certain types of microbes and cancer cells, they demonstrated good and encouraging findings for the potential to be used as antioxidants and antimicrobial agents. Full article

An effective approach for the large-scale fabrication of conducting polyaniline (PANI) using in situ anodic electrochemical polymerization on nickel foam which had been coated in aryl diazonium salt (ADS)-modified graphene (ADS-G). In the present work, ADS-G was used as a high surface-area support material for the electrochemical polymerization of PANI. The electrochemical performances of the ADS-G/PANI composites exhibited better suitability as supercapacitor electrode materials than those of the PANI. The ADS-G/PANI composites achieved a specific capacitance of 528 F g⁻¹, which was higher than that of PANI (266 F g⁻¹) due to excellent electrode–electrolyte interaction and the synergistic effect of electrical conductivity between ADS-G and PANI in the composites. These findings suggest that the ADS-G/PANI composites are a suitable composite for potential supercapacitor applications. Full article

Quantum dots (QDs) are emerging as promising candidates for innovative memristive materials, owing to their distinct surface, quantum size, and edge effects. Recent research has focused on tailoring QDs with specific organic molecules to fine-tune charge transfer states between the host and grafted species, as well as enhancing their dispersibility and processability. Violet phosphorus (VP), a newly discovered two-dimensional phosphorus allotrope, offers excellent carrier dynamics, predictable modifiability, and superior oxidation resistance, making it a promising contender in this domain. In this study, we synthesized a rich azobenzene-containing star-shaped polymer diazonium salt (AzoSPD) to functionalize violet phosphorus quantum dots (VPQDs), with the dual objectives of enhancing organic dispersibility and introducing photo-switching capabilities. The synthesized AzoSPD–VPQDs exhibit intramolecular charge transfer characteristics under electrical stimuli of ambient conditions, displaying significant non-volatile rewriteable memory properties and a substantial switching ratio exceeding 2 × 10³. Furthermore, the high resistance state (HRS) current can be enhanced by nearly 40 times under 465 nm illumination, enabling optoelectronic information sensing and storage within a single device. This work not only provides insights into enhancing the optoelectronic properties of QDs through functional organic molecular modification but also represents a pioneering exploration of the potential applications of VPQDs in novel memristors. Full article