ABSTRACT To develop high‐performance unsymmetrical bis(arylimino)acenaphthene‐nickel precatalysts, N‐phenyl and N‐naphthalen‐1‐yl groups were strategically selected as one‐side rigid N‐aryl arm without auxiliary alkyl substituents, enabling the diverse construction of ligands ( L2 ‐ L4 and L5 ‐ L8 ) and their corresponding nickel complexes ( Ni2 ‐ Ni4 and Ni5 ‐ Ni8 ). Upon treatment with either EASC or MMAO, all nickel complexes demonstrated moderate to high activities in polymerizing ethylene, achieving up to 16.1 × 10 6 g of PE (mol of Ni) −1 h −1 , and noticeably generated branched polyethylene waxes with narrow and lower molecular weights from 1.8 kg mol −1 to 24.5 kg mol −1 . Notably, these nickel‐based catalytic systems exhibited enhanced thermostability, with an optimum operational temperature of 60°C, outperforming their previously reported nickel analogs. Critically, the strategic modification of another N‐aryl groups enabled precise tuning of catalytic performance. Specifically, varying the positional isomerism of the di(4‐fluorophenyl)methyl group not only modulated the catalytic activities of the nickel complexes but also dictated the microstructural features—including molecular weight and branching degree—of the synthesized polyethylene waxes. A systematic analysis of the structure‐performance correlations has been conducted to elucidate how the strategic incorporation of sterically demanding, multi‐substituted N‐aryl fragments—in tandem with rigid N‐phenyl or N‐naphthalen‐1‐yl substituents—modulates catalytic performance.
ABSTRACT RuCo nanoclusters supported on expanded perlite (EP) were synthesized and evaluated as efficient catalysts for hydrogen generation via the methanolysis of ammonia borane (AB). EP, an inexpensive and environmentally benign support, was modified to enhance its surface properties and subsequently employed for metal loading. The resulting RuCo@EP catalyst exhibited good activity, achieving a hydrogen generation rate (HGR) of 5487 mL g −1 min −1 and a turnover frequency (TOF) of 94.5 h −1 at 30°C. Comprehensive kinetic studies revealed that the reaction follows first‐order kinetics with respect to AB concentration, with an apparent activation energy of 47.07 kJ mol −1 . Structural and morphological analyses (XRD, SEM–EDS, TEM, and BET) supported the successful incorporation and relatively uniform distribution of Ru and Co nanoparticles on the perlite surface. These findings demonstrate that RuCo@EP is a cost‐effective and highly active catalyst, highlighting the potential of natural mineral supports for sustainable hydrogen generation.
ABSTRACT Hybridity of the layered double hydroxides (LDHs) with metal–organic frameworks (MOFs) springs synergistic effects of tunable functionality, multi‐active sites, and stability for catalysis. Herein, the novel bifunctional nanocomposite NiFe‐LDH@MOF was prepared by solvothermal anchoring of dual acid–base ligand 2,5‐pyridinedicarboxylic acid (PDCA) onto the as‐prepared NiFe‐LDH. The layered conservation of LDH in nanocomposite NiFe‐LDH@MOF was recognized by X‐ray diffraction, microscopic images, energy‐dispersive X‐ray spectroscopy, surface area, and thermal analyses. Inductive coupled plasma analysis (ICP‐OES revealed 28.4 wt% nickel and 3.9 wt% iron in this bifunctional organometallic nanocomposite that is admirable catalytic activity in tandem Knoevenagel, Michael, and cyclization reactions to synthesize 2‐amino‐4H‐chromenes. Through the rewards of versatility, high product yields, rapidness, easy workup, and reusability, various chromenes were synthesized from aromatic aldehydes, malononitrile, and dimedone or β‐naphthol.
ABSTRACT The design and development of high‐performance electrocatalytic systems featuring multiple functionalities, excellent recyclability, and reusability constitute a vital and essential advancement in the field of green chemistry. Such innovative approaches significantly mitigate environmental impacts by substantially reducing the discharge of toxic and hazardous pollutants into ecosystems, while concurrently lowering the operational and production costs associated with chemical processes. In alignment with this principle, a novel magnetic electrode based on Fe 3 O 4 @SiO 2 ‐TGDM@Ni was strategically designed and developed. Within this core‐shell architecture, the Fe 3 O 4 @SiO 2 component imparts strong magnetic properties that facilitate straightforward recovery and repeated use of the electrode through simple magnetic separation. The triaminoguanidine dimethoxybenzene (TGDM) layer simultaneously functions as an electrolyte mediator/support and a co‐catalytic promoter, enhancing overall system efficiency. Meanwhile, the Ni NPs serve as the primary electrocatalyst, and thanks to the integrated magnetic recoverability, the entire electrode can be easily retrieved, reused, and assessed for minimal metal leaching. The practical performance of this multifunctional electrode was rigorously evaluated in the electrocarboxylation reaction. The electrochemical synthesis of 2‐phenylpropanoic acid derivatives 3(a–l) was performed under remarkably mild conditions (room temperature, iPrOH) using a constant current of 7 mA for just 1 h. These optimized conditions afforded the products in excellent isolated yields between 90% and 97%. Impressively, it maintained robust catalytic activity and structural integrity across up to 10 consecutive recycling cycles with negligible performance degradation. The core‐shell structured Fe 3 O 4 @SiO 2 ‐TGDM@Ni material underwent comprehensive characterization using a wide array of techniques, including SEM, EDS, TEM, FT‐IR, BET, TGA, VSM, XPS, CV, ICP‐OES and mass spectrometry. Similarly, the resulting 2‐phenylpropanoic acids 3(a‐l) were fully identified and confirmed through melting point determination, 1 H NMR, 13 C NMR spectroscopy, and elemental analysis (CHN).
ABSTRACT The selective hydrogenation of nitroarenes is an indispensable reaction for the production of high‐value arylamines in fine chemical and pharmaceutical industries. However, it remains challenging to develop low‐cost, high‐efficiency, and durable non‐noble metal catalysts for such reactions under mild conditions. In this contribution, a novel Fe‐Fe 3 C‐Fe 3 O 4 embedded in nitrogen‐doped carbon (Fe‐Fe 3 C‐Fe 3 O 4 @CN‐l) was successfully prepared using biomass tannic acid as a sustainable precursor via a facile Zn‐assisted evaporation‐pyrolysis route. Structural analyses based on XRD, TEM, BET, Raman, and XPS confirm that the evaporation of Zn species during pyrolysis effectively regulates the Fe‐based nanoparticles, improves metal dispersion, enriches carbon defects, increases specific surface area, and generates abundant Fe‐N species. Using hydrazine hydrate as a green hydrogen donor, the optimized catalyst exhibits outstanding hydrogenation performance, achieving a nitrobenzene conversion of 98.5% and aniline selectivity above 99.8%. Moreover, the catalyst possesses excellent substrate adaptability toward various functionalized nitroarenes and prominent reusability without noticeable performance decay after five consecutive cycles. This work provides a facile, green, and universal strategy for the rational design and fabrication of high‐performance biomass‐derived non‐noble metal catalysts for advanced hydrogenation applications.
ABSTRACT Two hydrazone‐based Schiff base ligands were synthesized through condensation reaction between 9‐formyl‐8‐hydroxyjulolidine and 2‐hydrazinobenzothiazole or 2‐hydrazinoquinoline. These ligands were subsequently coordinated to the precursor complex [RuHCl(CO)(EPh₃)₃] (E = P or As), yielding a new family of Ru(II) complexes with the general formula [RuH(CO)(EPh₃) 2 L] ( C1–C4 ) (E = P or As; L = 9‐formyl‐8‐hydroxy‐julolidine‐derived hydrazone ligands). Micro analyses and many spectroscopic methods, such as FT‐IR, UV–Vis, NMR spectroscopy, and electrospray ionization (ESI) mass spectrometry, were used to conform the formation of ligands and their associated Ru(II) complexes. Solid‐state structure analysis of complexes ( C1 and C3 ) confirmed distorted octahedral coordination geometries around the Ru(II) center. To assess the biological potential relevance of the newly synthesized complexes, molecular docking studies were first performed, which revealed favorable binding interactions with the selected target proteins. Additionally, intermolecular interactions in the crystalline state were investigated using Hirshfeld surface analysis and two‐dimensional fingerprint plots, which revealed H···H contacts as the main contribution. The in vitro antiproliferative properties of the Ru(II) complexes were assessed against a noncancerous cell line (MCF‐10A) and two cancer cell lines (MCF‐7 and HepG‐2). The results demonstrated pronounced anticancer activity relative to cis platin, with complex C2 exhibiting exceptional cytotoxicity toward HepG‐2 cells. Furthermore, flow cytometry study revealed that treatment with complex C3 predominantly induced late apoptosis in HepG‐2 cells, whereas complex C2 primarily triggered early apoptotic cell death.
ABSTRACT A zinc complex bearing imino‐phosphanamidinate chalcogenide ligands efficiently promotes the ring‐opening polymerization (ROP) of rac ‐lactide ( rac ‐LA) and ε‐caprolactone (ε‐CL), as well as their copolymerization. The complex demonstrated good control over the ROP of rac ‐LA, affording isotactic poly (lactic acid) (PLA) with high stereoselectivity ( P m = 0.82) and narrow dispersity (Ð < 1.3). One‐pot ring‐opening copolymerization (ROCOP) of rac ‐LA and ε‐CL in the presence of the zinc complex has been shown to produce random copolymers with predictable molecular weights. The fact that the randomization of the copolymers is driven concurrently by the formation of a gradient/partially random copolymer species and slow transesterification was established via in situ NMR spectroscopy. PLA‐ co ‐CL copolymers with varying CL/LA ratios were synthesized, displaying a single glass transition temperature ( T g ) within the range between the T g values of the corresponding homopolymers.
ABSTRACT An improved methodology for synthesis of benzimidazole‐fused quinazolines and pyrimidines was developed by recyclable magnetic Cu‐MOF‐74‐catalyzed nucleophilic aromatic/vinylic substitution and cyclization of 2‐(2‐bromoaryl/vinyl)azoles and indoles with 2‐aminoazoles. The reaction could apply to a wide scope of starting materials containing electron‐donating or ‐withdrawing substituents on bromophenyl and azole/indole moieties. The catalyst could be recovered and reused up to four times without significant loss of catalytic activity.
ABSTRACT A series of copper(I) complexes with phosphine and sulfur donors was synthesized and characterized using multinuclear NMR spectroscopy and single‐crystal X‐ray crystallography techniques. These complexes were investigated for their ability to facilitate the cross‐coupling reaction of terminal alkynes with dialkylphosphites. Among the tested complexes, a bimetallic complex with reduced steric hindrance and cuprophilic interactions exhibited high activity and selectivity in coupling reactions. The copper(I)‐based bimetallic complex demonstrated significant catalytic activity in the cross‐coupling of a broad range of dialkylphosphites with phenyl acetylene under low catalyst loading at refluxing temperature of acetonitrile.
The impact of electron-donating groups (EDGs) at the ortho-phenoxy position of phosphino-phenolate nickel catalysts on ethylene polymerization and copolymerization with polar monomers was systematically investigated. Three phosphino-phenolate catalysts based on EDG (Ni1, -OMe; Ni2, -OH; Ni3, -CH2OH) were designed and synthesized, which are moderately active single-component catalysts for ethylene polymerization at elevated temperatures (up to 150 degrees C), producing high molecular weight linear polyethylene with a melting point as high as 136.0 degrees C. The reduced electron-donating ability of EDG decreased the activity and molecular weight. Most importantly, a single crystal of the Ni-Li heterobimetallic complex, based on Ni1 and a lithium Lewis acid unit, was confirmed by X-ray diffraction analysis. Besides, Ni1 and Ni2 demonstrated superior performance in ethylene/polar monomers copolymerization, achieving 1.9-mol% polar monomer incorporation, resulting in excellent surface properties of the copolymer. The impact of ortho-phenoxy EDGs in phosphino-phenolate nickel catalysts is explored, revealing their high thermal stability and activity in ethylene polymerization to yield high molecular weight linear polyethylene. Notably, these catalysts exhibit excellent performance in ethylene copolymerization with polar monomers, significantly enhancing copolymer surface properties.
Efficient catalytic oxidation through dioxygen activation under gentle conditions is a long-standing challenge in industry. The present work introduces a catalytic oxidation of short- to middle-length aliphatic aldehydes to the corresponding acids through Lewis acid enhanced dioxygen activation by iron (II) complex. It was found that the presence of a modest Lewis acid such as Ca (OTf)2 could substantially improve the catalytic efficiency, and an unusual odd-even effect in catalysis was observed for the corresponding acid formation. The quenching experiments with 1,4-benzoquinone indicated that the iron (III) superoxo species, which is the primary active oxygen species after dioxygen activation, was one of the key active oxygen species for the oxidation. The promotional effect of Ca (OTf)2 was attributed to its electrostatic interaction with the iron (III) superoxo species, that is, LFeIII-O2 -center dot & centerdot;& centerdot;& centerdot;Ca2+, which stabilized this intermediate, thus drove dioxygen activation to its formation and improved the catalysis. A simplified mechanism was proposed to rationalize this Lewis acid enhanced dioxygen activation by iron (II) complex for aliphatic aldehyde oxidations to the corresponding acids.
Five new dimethyltin(IV) addition complexes with the general formula [SnMe2Cl2(HL1-5)2] (HSR 1-5) were synthesized via a 1:2 M reaction between dimethyltin(IV) dichloride and a series of 4-N-diethylaminosalicylaldimine Schiff bases. The ligands employed were HL1 = 4-N-diethylaminosalicylidene-1-aminobenzene, HL2 = 4-N-diethylaminosalicylidene-2-methyl-1-aminobenzene, HL3 = 4-N-diethylaminosalicylidene-3-methyl-1-aminobenzene, HL4 = 4-N-diethylaminosalicylidene-4-methyl-1-aminobenzene, and HL5 = 4-N-diethylaminosalicylidene-2,4,6-trimethyl-1-aminobenzene. The complexes were characterized by FT-IR, (1H, 13C, and119Sn) NMR, HRMS spectroscopy and elemental analysis (C, H, N, Cl, and Sn). The molecular structures of HSR 1, HSR 2, HSR 4, and HSR 5 were elucidated by single-crystal X-ray diffraction. All these complexes feature a Sn(IV) center in a distorted octahedral geometry, where the six coordination sites are occupied by two trans chloride ions, two trans methyl groups, and two trans oxygen atoms derived from the Schiff base ligand. The structural analysis reveals that the tin atom exhibits an all-trans octahedral coordination geometry, with the two 4-N-diethylaminosalicylaldimine Schiff base ligands binding through their phenolic oxygen atoms as iminium-phenolato zwitterions. The complexes exhibited moderate antibacterial activity against all tested strains, including E. coli, P. aeruginosa, S. aureus, and S. pyogenes, with MIC values >= 200 mu g/mL. Activity against the fungal strains C. albicans and A. niger was also assessed. DNA cleavage studies (agarose gel electrophoresis) exhibited that the complexes possess significant potency to cleave DNA. Their photophysical properties were also investigated, and UV-Vis absorption and fluorescence measurements provided insight into the electronic behavior of the complexes, with complex HSR 1 showing the highest fluorescence intensity.
A novel ruthenium (II) PNN pincer complex (Ru-1) containing a bipyridine ring was designed and synthesized in this study, and its performance as a homogeneous catalyst in olefin oxidation reactions was systematically investigated. Raw materials were prepared via Schlenk technique, and ligand L1 as well as the target complex Ru-1 were synthesized through multi-step reactions. The structure of Ru-1 was characterized by 1H NMR, 31P NMR, high-resolution mass spectrometry (HR-MS), and X-ray crystallography, which confirmed the configuration of Ru-1. Catalytic performance studies showed that Ru-1 exhibited excellent catalytic activity and stability in styrene oxidation: when the catalyst dosage was as low as 1.00 & times; 10-7 mol%, 100% conversion could still be achieved, with a turnover number (TON) exceeding 1.0 & times; 109 and a maximum turnover frequency (TOF) reaching 5.0 & times; 107 h-1. Using H5IO6 as the oxidant and ethyl acetate/water (1:1) as the mixed solvent, the selectivity for benzaldehyde was up to 99.0% at room temperature, which effectively suppressed side reactions. In addition, this catalyst had broad substrate compatibility and could efficiently catalyze the oxidation of styrene derivatives, internal olefins, alkynes, and natural products with a styrene structure, generating the corresponding aldehydes and ketones, respectively. This study provides an efficient and green catalytic system for the selective oxidation of olefins, highlighting the application value of bipyridine-based PNN ligands in the field of organometallic catalysis.
In contrast to 1,2-di-trimethylsilyl styrenes, which in the presence of catalytic amounts of Pd nanoparticles [generated from Pd2dba3/Ag(I)] undergo with aryl iodides a stereoselective C-H Mizoroki-Heck arylation pathway, the arylation of monosilylated beta-trimethylsilyl styrenes under the same conditions occurs via a Hiyama-type C-Si coupling pathway leading to trans-stilbenes. This catalytic system enables the nonactivated in Hiyama-coupling trimethylsilyl group to react promptly relative to the competing Mizoroki-Heck pathway. A side product of this process, 1,1 '-diarylethylene, can be completely eliminated using AgBF4 as silver salt, and 1,3-dimethyl-2-imidazolidinone (DMI) as an environmentally friendlier solvent over the frequently used in Pd-catalyzed reactions N,N-dimethylformamide or N-methyl-2-pyrrolidone, in which the current arylation is less chemoselective. The coupling reaction tolerates the presence of boryl substituents in aryl iodide. From the mechanistic point of view, the process involves syn-arylpalladation followed by an E2-type elimination of silyl group and palladium species.
A series of novel silver(I) complexes bearing N-heterocyclic carbene (NHC) ligands were successfully synthesized and characterized using spectroscopic methods, elemental analysis, and X-ray diffraction techniques. Single-crystal X-ray diffraction analysis establishes complex 2f as a neutral monomeric silver(I) complex [Ag(L)(2)]Cl. The compound crystallizes in the monoclinic space group P2(1)/n (Z = 4) with unit-cell parameters a = 12.698(3) & Aring;, b = 9.872(2) & Aring;, c = 24.428(5) & Aring;, beta = 91.149(9)degrees. Hirshfeld surface analysis reveals that crystal packing is governed by dispersion-dominated H center dot center dot center dot H contacts (47.3%), supplemented by nonclassical C-H center dot center dot center dot N (17.9%) and C-H center dot center dot center dot Cl (6%) hydrogen bonds, along with enriched pi-pi stacking interactions. Powder X-ray diffraction confirmed the phase purity of the bulk samples. The electronic structures of the complexes were further elucidated by elemental analysis and FT-IR spectroscopy, supporting coordination via carbene carbon atoms. In parallel, the antibacterial activity of the synthesized compounds was evaluated against representative Gram-positive and Gram-negative bacterial strains. Several silver-NHC complexes demonstrated pronounced antibacterial effects, with inhibition zone diameters ranging from 11.94 to 28.99 mm and minimum inhibitory concentration (MIC) values between 0.073 and > 10 mg/mL. Among these, complex 3g exhibited the highest antibacterial potency, particularly against Listeria monocytogenes (MIC = 0.073 +/- 0.05 mg/mL), alongside significant activity against Staphylococcus aureus (MIC = 0.621 +/- 0.05 mg/mL). By contrast, complex 3f showed strong activity against the two Gram-negative strains, respectively, Pseudomonas aeruginosa (MIC = 0.075 +/- 0.05 mg/mL) and Salmonella enterica (MIC = 0.076 +/- 0.05 mg/mL). Cytotoxicity study of the silver(I) complexes 3 was evaluated against the two human cancer cell lines MDA-MB-231 and MCF-7. These findings highlight the potential of NHC-silver complexes as versatile agents in medicinal chemistry and provide valuable insights into their structure-function correlations.
ABSTRACT In this study, N‐ZnO/g‐C 3 N 4 /GO nanocomposites were successfully fabricated via the coprecipitation method. Characteristics of synthesized photocatalysts were analyzed using FTIR, XRD, FESEM, EDX mapping, TEM, and PL. The photocatalytic performance of the synthesized nanoparticles was evaluated for the degradation of methylene blue (MB) under visible light. The N‐ZnO/g‐C 3 N 4 /GO nanocomposite exhibited significantly enhanced performance, achieving 91% MB degradation within 60 min, whereas pure ZnO degraded only 25.38% after 90 min. Incorporating the synthesized photocatalysts into the dynamic membrane had a significant effect on the rejection rate of MB and permeation flux. While the pure PES membrane rejected only 30% of MB, the self‐forming dynamic membrane (SFDM) and precoated dynamic membrane (PCDM) containing the nanocomposite achieved > 85% and ~98% degradation within 15 and 10 min, respectively. These results demonstrate a strong synergistic effect between the photocatalyst and the dynamic membrane, leading to substantially improved dye removal and permeation performance.
A novel nanocomposite based on agricultural wastes was obtained. The adding of green TiO2 nanoparticles to clay and natural cellulose, cellulose@clay/TiO2 nanocomposite, was gained. This nanocomposite was characterized using ICP, FT-IR, UV, and XRD techniques. The nanocomposite was analyzed by FT-IR, SEM, TEM, XRD, UV-Vis spectroscopy, DLS, zeta potential analysis, atomic absorption spectroscopy, and elemental analysis. XRD analysis successfully confirmed the presence of cellulose, TiO2, and clay in the nanocomposite structure. In contrast, elemental analysis confirmed the existence of Si, C, O, Al, Al2O3, and Ti (TiO2), which confirmed the successful synthesis of the nanocomposite. Moreover, based on antibacterial activities, the disc diffusion method and growth percentage inhibition were determined under visible-light and dark conditions. The disc diffusion assay revealed the antibacterial activity of the nanocomposite on Gram-positive strains, especially in the presence of visible light illumination. In this study, in addition, the inhibition of Gram-positive and Gram-negative strains by the new nanocomposite and the antibacterial activity of the cellulose@clay/TiO2 nanocomposite were confirmed. As a result, the environmentally compatible nanocomposite showed much more effective deterrence of the growth ability of Gram-positive bacteria than Gram-negative strains under visible light conditions.
African trypanosomiasis and leishmaniasis are vector-borne infectious diseases that affect both humans and animals. If left untreated, these neglected tropical diseases can be fatal. There are tens to thousands of new cases of both diseases reported by the WHO annually. The clinically available treatments are not practical because they suffer from severe adverse effects, impractical administration and increased instances of parasitic resistance. This emphasises the need for the development of new drugs to treat these diseases. In the search for such drugs, we investigated a series of ferrocenyl-based hydantoin/rhodanine derivatives. Herein, we report the design, synthesis, electrochemistry and in vitro biological activity of these derivatives against amastigotes of Leishmania donovani, as well as blood-stage trypomastigotes of Trypanosoma brucei brucei, Trypanosoma brucei gambiense, Trypanosoma brucei rhodesiense, Trypanosoma equiperdum and Trypanosoma evansi. Ferrocenylrhodanine analogues 19 and 23 were identified as a potential leishmanicidal early lead and hit, respectively, whereas 3-hydantoin-containing analogue 11 was identified as an antileishmanial hit. Ferrocene derivatives 23 and 11 were tested for ROS activity, and mitochondrial dysfunction is suspected to play a role in their mechanisms of action. Nine trypanosomacidal hits were also identified, of which ferrocenylrhodanine analogue 21 was the most prominent. These compounds are accordingly suited for further investigation as antitrypanosomatid drugs in the future. This may include increasing compound stability and solubility.
A one-dimensional chain coordination polymer, {Cd4(bdppy)2(H2O)6}n (IMU-Cd), was initially synthesized via a solvothermal reaction using the ligand 2,6-bis(3,4-dicarboxyphenoxy)pyridine (H4bdppy). Subsequently, Eu3+ ions were incorporated into IMU-Cd via a one-pot synthesis to yield its postmodified composite material, Eu@IMU-Cd. The experimental investigations showed that Eu@IMU-Cd remained stable in different solvents as well as over a wide pH range. It was found that Eu@IMU-Cd was able to emit the characteristic peaks of Eu3+ ion and produced a fluorescence quenching effect in the presence of methylparaben (MP) and thus could be used as a fluorescent probe for the detection of MP. Moreover, its identification of MP by Eu@IMU-Cd exhibited high selectivity, reusability, and anti-interference, and the limit of detection of MP was found to be 25.6 nM. A combination of experiments and theoretical calculations was used to elucidate the detailed fluorescence mechanism for the identification of MP by Eu@IMU-Cd. Moreover, the films based on Eu@IMU-Cd were fabricated to achieve visual detection in the presence of MP. It is worth emphasizing that the experiments of determining MP in real liquor samples displayed that the spiked recovery was located in the range of 88.64%-97.86% with the RSD of less than 1.82%, which indicated that Eu@IMU-Cd had an outstanding capability for the exploration of MP in actual samples.
