Room Temperature Reaction Research Articles

Ternary ZnO/Co3O4/CuO heterostructure nanocomposites derived from trimetallic metal-organic frameworks for efficient electrocatalytic water oxidation

Enhancing the electrocatalytic performance of transition-metal oxide catalysts by optimizing the active center at the multi-component heterointerface is a daunting task. Herein, the three-component ZnO/Co3O4/CuO heterostructure composite catalyst was effectively produced through a room-temperature precipitation reaction, followed by calcination in air. The ZnO/Co3O4/CuO ternary heterostructure catalyst showed superior oxygen evolution reaction (OER) performance, characterizedby a low overpotential (312 mV at 10 mA cm−2) and Tafel slope (83.5 mV dec-1) compared to the ZnO, Co3O4, ZnO/CuO, ZnO/Co3O4, and Co3O4/CuO catalysts. The research shows that the property of electrocatalytic oxygen evolution is greatly enhanced due to the combined impact of each component.

Room-temperature selective cyclodehydrogenation on Au(111) via radical addition of open-shell resonance structures

Cyclodehydrogenation is an important ring-formation reaction that can directly produce planar-conjugated carbon-based nanomaterials from nonplanar molecules. However, inherently high C–H bond energy necessitates a high temperature during dehydrogenation, and the ubiquity of C − H bonds in molecules and small differences in their bond energies hinder the selectivity of dehydrogenation. Here, we report a room-temperature cyclodehydrogenation reaction on Au(111) via radical addition of open-shell resonance structures and demonstrate that radical addition significantly decreases cyclodehydrogenation temperature and further improves the chemoselectivity of dehydrogenation. Using scanning tunneling microscopy and non-contact atomic force microscopy, we visualize the cascade reaction process involved in cyclodehydrogenation and determine atomic structures and molecular orbitals of the planar acetylene-linked oxa-nanographene products. The nonplanar intermediates observed during progression annealing, combined with density functional theory calculations, suggest that room-temperature cyclodehydrogenation involves the formation of transient radicals, intramolecular radical addition, and hydrogen elimination; and that the high chemoselectivity of cyclodehydrogenation arises from the reversibility and different thermodynamics of radical addition step.

Molecular imprinting sensor based on zeolitic imidazolate framework derived Co, N-doped carbon loaded on reduced graphene oxide toward the determination of dopamine.

Anovel voltammetric sensor designed for dopamine(DA) detectionis presented utilizing a combination of zeolitic imidazolate framework (ZIF-67) derived cobalt and nitrogen-doped carbon on reduced graphene oxide (Co-N-C/rGO). ZIF-67 cubic crystals were synthesized in situ and deposited onto the graphene oxide (GO) surface through room-temperature reactions. High-temperature calcination resulted in partially collapsed cubic and spherical carbon, while simultaneously reducing GO to rGO. A molecular imprinting resorcinol polymer (MIP) membrane was also in situ applied to the Co-N-C/rGO/glassy carbon electrode (GCE) via electropolymerization. Analyses using cyclic voltammetry, electrochemical impedance, and pulse voltammetry reveal that the modified MIP/Co-N-C/rGO/GCE electrodes show improved electroconductivity and notable electrochemical reactivity towards dopamine. After optimizing detection parameters, the sensor demonstrates a wide linear detection range of 0.01-0.5 and 0.5-100μmol/L, with a limit of detection (LOD) of 3.33nmol/L (S/N = 3). Additionally, the sensor displays strong robustness, including excellent selectivity, significant resistance to interference, and long-term stability. It also shows satisfactory recovery in detecting spiked real samples.

Investigation of Phosphazene Superbase Interactions with [PCl2N]3.

In this study, the reaction between phosphazene superbases and a chlorophosphazene trimer ([PCl2N]3) has been investigated. In this room temperature reaction, the phosphazene superbase (Me2N)3PN(Me2N)2P═NEt, commonly known as P2Et, was shown to behave as a nucleophile, displacing one of the chlorides from [PCl2N]3 and producing the tadpole-like structure 1. The reaction described herein is one of the few instances of a phosphazene superbase behaving as a nucleophile rather than a Brønsted base. Once formed, this structure contains contrasting reactivity, containing a weakly basic phosphazene head while maintaining a highly basic phosphazene tail of the tadpole. The mechanism of the reaction was explored by investigating the potential energy surface through density functional theory calculations at the B3LYP/6-311+G(d,p) level of quantum mechanical theory. It was determined that the reaction of P2Et with [PCl2N]3 followed a stepwise process beginning with the substitution of P2Et onto [PCl2N]3 with the concurrent loss of chloride. Subsequently, the chloride attacks the ethyl group of the P2Et moiety, and ethyl chloride is released, producing 1. Compound 1 was further characterized via 31P NMR spectroscopy, mass spectrometry, and X-ray crystallography.

Enhanced detection of catecholamines in human urine using Cis-diol-microporous organic networks with PT-SPE and HPLC-MS/MS

A novel cis-diol-microporous organic networks (MONs-2OH) material was synthesized via room temperature and Sonogashira coupling reactions, which exhibits exceptional adsorption properties for catecholamines (CAs). MONs-2OH demonstrates robust hydrogen bonding and π-π stacking interactions, crucial for effective adsorption. The MONs-2OH was incorporated into pipette tip solid-phase extraction and developed a new method for detecting CAs in human urine using HPLC-MS/MS. Characterization of the adsorbent revealed its high stability, large specific surface area, abundant phenolic hydroxyl groups, rapid extraction speed, and superior adsorption efficiency. The method achieved a wide linear range (0.5–500 ng/mL), low detection limits (0.06–0.26 ng/mL), high accuracy (90.4 %-99.4 %), and excellent precision (RSD ≤ 10 %). Comparative studies showed MONs-2OH outperforms commercial adsorbents in terms of recovery and adsorption capacity. The results underscore the potential of MONs-2OH for rapid and sensitive CAs determination, offering significant advantages for the auxiliary diagnosis of depression and enhancing the application of PT-SPE in sample pretreatment.

Room Temperature Regioselective Debenzylative Cycloetherification Reaction.

A regio- and stereoselective debenzylative cycloetherification (DBCE) reaction of protected hexoses to form stereodefined hydroxylated tetrahydrofurans of synthetic utility has been investigated under very mild room temperature reaction conditions. This study revealed the potential application of the DBCE reaction of simple, abundant starting materials to access stereochemically rich tetrahydrofuran compounds under mild reaction conditions.

Green co-solvent-assisted one-pot synthesis of high-performance flexible lignin polyurethane foam

Although lignin is a promising candidate as a source of polyol for producing eco-friendly polyurethane foam (PUF), its direct application has limitations, primarily stemming from the brittleness of the resulting products and poor processibility at high lignin loadings. To address these technical challenges, we introduced an effective co-solvent for the lignin-based polyurethane foams (LPUFs) with up to 80 wt% of lignin substitution for petroleum polyols. As a green co-solvent that involves carbon dioxide fixation during its production, propylene carbonate (PC), was blended with lignin and improved the distribution of lignin by decreasing the viscosity, providing a room-temperature reaction. The LPUFs demonstrated a comparable thermal insulation performance (R-values greater than 5 in−1) with commercially available PUF with a uniform size of closed-cell structure induced by the reduced viscosity of lignin-based polyol. LPUFs also showed enhanced fire retardancy and moisture resistance compared to the control PUFs, benefiting from lignin’s intrinsic fire-resistant and hydrophobic properties. To mitigate the brittleness issue at high lignin loadings, flexible polyethylene glycols (PEGs) with a high molecular weight (i.e., PEG-1000) were dissolved in PC at room temperature to further improve the mechanical strength of LPUFs. The compressive strength of LPUFs with 80 wt% lignin substitution content was remarkably improved to 226 kPa by the employment of co-solvent and PEG-1000 compared to the control PUF (<140 kPa). Moreover, the flexibility of the LPUFs was successfully controlled by simply adjusting the PEG-400/PEG-1000 ratio. The results of this study provide valuable insights for accelerating and broadening the utilization of lignin in sustainable materials and manufacturing areas.

Nondissociative Activated Dihydrogen Binding on CeO2 Revealed by High-Pressure Operando Solid-State NMR Spectroscopy.

Dihydrogen complexes, which retain the H-H bond, have been extensively studied in molecular science and found to be prevalent in homogeneous and enzymatic catalysis. However, their counterparts in heterogeneous catalysis, specifically nondissociative chemisorbed dihydrogen binding on the catalyst surface, are rarely reported experimentally. This scarcity is due to the complexity of typical material surfaces and the lack of effective characterization techniques to prove and distinguish various dihydrogen binding modes. Herein, using high-pressure operando solid-state NMR technology, we report the first unambiguous experimental observation of activated dihydrogen binding on a reduced ceria catalyst through interactions with surface oxygen vacancies. By employing versatile NMR structural and dynamical analysis methods, we establish a proportional relationship between the degree of ceria surface reduction and dihydrogen binding, as evidenced by NMR observations of H-D through-bond coupling (JHD), T1 relaxation, and proton isotropic chemical shifts. In situ NMR analysis further reveals the participation of bound dihydrogen species in a room-temperature ethylene hydrogenation reaction. The remarkable similarities between surface-activated dihydrogen in heterogeneous catalysis and dihydrogen model molecular complexes can provide valuable insights into the hydrogenation mechanism for many other solid catalysts, potentially enhancing hydrogen utilization.

Cellulose-based fluorescent chemosensor with controllable sensitivity for Fe3+ detection

Polymer-based sensors, particularly those derived from renewable polymers, are gaining attention for their superior properties compared to organic small molecules. However, their complex preparation and poor, uncontrollable sensitivity have hindered further development. Herein, cellulose-based polymer photoluminescence (PL) chemosensors were fabricated using a straightforward and adjustable strategy. Specifically, water-soluble cellulose acetoacetate (CAA) was used as the substance for the in-situ synthesis of 1,4-dihydropyridine (DHPs) fluorescent rings on cellulose chains via a catalyst-free, room-temperature Hantzsch reaction. Benefiting from the synergetic through-space conjugation of DHPs rings and semi-rigid cellulose chains with heteroatoms, the sensors exhibit bright and stable PL properties. Based on this performance, the cellulose-based sensor excels in the specific recognition of Fe3+ in aqueous systems, showing exceptional selectivity, stability, and anti-interference performance due to the synergy between the inner filter effect (IFE) and intramolecular charge transfer (ICT). Theoretical calculations confirm the role of the extended π-conjugated structure at the DHPs-4 position in modulating the sensor sensitivity, achieving a low limit of detection (LOD) of 0.48 μM. Furthermore, the versatility of the Hantzsch reaction shows the potential of this strategy for developing a new generation of biomass-based polymer portable sensors for real-time and on-site detection.

Thermal/photothermal-induced flexible folding and rapid soft-to-rigid transition in dark fiber composite structural components

Foldable and deployable structures find extensive applications in space deployment equipment, yet dark fiber composites (DFCs) utilized for crafting these structures still grapple with the trade-offs among resin flow, curing speed, and degree of cure. To address these issues, a novel thermal/photothermal (TPT) system was developed, leveraging two-stage and photo-induced photothermal synergistic techniques. The first stage involves a room-temperature click reaction, producing a gel intermediate state with an impressive fracture elongation rate of up to 123.15 %, allowing for arbitrary flexible folding and deployment. The second stage involves photo-induced photothermal curing, where the heat generated during the curing process (reaching temperatures up to 131.5 °C) can trigger thermal curing. The second-stage sample can achieve a Young's modulus up to 22,000 times that of the first stage. When applied in the fabrication of DFCs, the TPT system significantly enhances the curing degree of the resin on the backside of the DFCs, achieving a rapid soft-to-rigid transformation within 1 min. This represents a significant improvement over thermal curing in terms of speed and energy consumption. The use of DFCs in structural components has demonstrated their capability for flexible folding and rapid soft-to-rigid transformation.

Green heterogeneous nickel–chromium oxide catalyst for solvent-free, room-temperature Knoevenagel condensation reaction

Green heterogeneous nickel–chromium oxide catalyst for solvent-free, room-temperature Knoevenagel condensation reaction

Chinese-Lantern shaped [MnII2MnIII6NaI3] cluster assembled from Schiff base and azide bridges: Synthesis, magnetic study and catecholase-like activity

A multisite Schiff base, H2damp, derived from the condensation of o-vanillin and a sterically constrained amino-alcohol (2-amino-2-methylpropan-1-ol) was utilized to isolate a new mixed valence heterometallic complex [Na3MnIII6MnII2(damp)6(µ4-O)2(µ1,3-O2CCH3)2(µ1,1-N3)6(µ1,1,3-N3)(H2O)2]·5H2O·CH3OH (1). Room temperature reaction of H2damp in MeOH with Mn(II) acetate and NaN3 provided the complex having MnII2MnIII6NaI3 core. X-ray structure determination revealed the use of azide ancillary ligands for the growth of the complex on ligand-bound MnIII3O fragments. The variable temperature magnetic characterization of 1 revealed intramolecular anti-ferromagnetic exchange interactions. Complex 1 also showed catalytic property for the aerial oxidation of 3,5-di-tert-butyl catechol (3,5-DTBCH2) with a turnover number (kcat) of 392 h−1. EPR and mass spectrometric analysis established the probable mechanism of catalytic oxidase reactivity on the model substrate. In EPR study the characteristic peak at g ∼ 2 allowed us to spot the presence of an organic radical confirming the conversion of DTBCH2 to DTBQ in radical pathway.

New half-sandwich ruthenium(II) complexes of chelating (SS) organochalcogen ligands and their application as transfer hydrogenation catalysts

Room temperature reactions of [(η6-arene)Ru(μ-Cl)Cl]2 (arene = p-cymene) with three new bidentate (SS) organochalcogen ligands, 2a–c (2a: 1,1’-ethylenebis(3-ethyl-imidazole-2-thione), 2b: 1,1’-ethylenebis(3-propyl-imidazole-2-thione), 2c: 1,1’-methylenebis(3-ethyl-imidazole-2-thione)), and in situ anionic exchange with KPF6 afforded the corresponding new 18-electron half-sandwich [(η6-arene)RuLCl]PF6 complexes 3a–c (3a: L = 2a, 3b: L = 2b, 3c: L = 2c). The Ru(II) complexes and the organochalcogen ligands were fully characterized by spectroscopic and analytical techniques. Solid state single crystal X-ray diffraction analysis of 3a–c displayed the Ru(II) center in the expected piano stool geometry. The catalytic activities of the half-sandwich ruthenium complexes toward the transfer hydrogenation of ketones to their corresponding alcohols were investigated using 2-propanol as a hydrogen source and solvent. All three Ru(II) complexes exhibited excellent catalytic activity for the transfer hydrogenation of ketones in the order 3b > 3a > 3c at an appreciably low catalyst loading of 0.5 mol% under a minimal alkaline condition of 10 mol% KOH. The catalytic activities of the complexes are influenced by the length of the alkyl spacer and the steric bulk of the N-substituents on the chelating organochalcogen ligand framework.

Fabrication of cobalt-doped ZnS thin films by successive ionic layer adsorption and reaction for UV–visible photodetectors on flexible substrate

Photodetectors are widely employed in research and innovation, necessitating swift response times, precision, and stability. However, their application in commercial and industrial settings is hindered by limited flexibility and a constrained capacity to respond across a broad spectrum. In this study, we adopted a facile, cost-effective, and room temperature Successive Ionic Layer Adsorption and Reaction (SILAR) technique to craft thin films of Cobalt-doped ZnS on a flexible paper substrate. The Cobalt doping, with varying wt.% (0, 0.5, 1, and 1.5) exhibiting excellent responsivity to both UV and visible spectra. Zinc Sulfide (ZnS), renowned for its wide bandgap, serves as a versatile semiconductor, making it an ideal candidate for photodetectors. The introduction of Cobalt broadened the responsivity of ZnS, covering a wide spectrum, including UV and visible regions. Structural confirmation of the material was achieved through XRD and Raman analyses. Scanning Electron Microscopy revealed the aggregated spherical nanostructure of ZnS on the cellulose substrate. Verification of Cobalt presence in the ZnS thin film and assessment of elemental oxidation states were conducted using XPS. Temporal response and I–V characteristics of the device were evaluated under varying light conditions, specifically at wavelengths of 325 nm and 700 nm at different intensities. Responsivity calculations yielded values of 22.5 mA/W for UV illumination (light intensity 0.6 mW/cm2) and 37.6 mA/W (light intensity 0.4 mW/cm2) for visible light, with corresponding response times recorded as 1.45 s and 2.13 s, respectively. In addition to performance assessments, bending cycle studies were conducted, demonstrating the excellent flexibility of the device up to 800 cycles. The Cobalt-doped ZnS device, as fabricated, emerges as a promising material for energy harvesting.

The art of Lithiation Revisited: Solvent-free room temperature reaction

The lithiation reaction holds immense significance across various branches of chemistry, particularly in the realm of electrochemical energy storage. Here, we report a new method that enables a solvent-free process at room temperature, exhibiting remarkably swift reaction kinetics. Through this process, the chemical integration of Li+ into charged materials based on transition metals is achieved using lithium iodide, LiI. An evident application of this method lies in advancing the direct recycling of cathode materials reclaimed from spent batteries. Notably, the process facilitates the efficient and direct recycling of spent Li(1-x)FePO4 cathode material, sourced from a commercial LIB, without the need for any solvents or heat treatments. The regenerated material exhibits a fully reversible capacity of approximately 168 mAh/g against Li metal, even under high current density conditions, with a consistently stable coulombic efficiency surpassing 99 % over 45 cycles. This regenerative approach holds the potential for seamless extension to other LIB cathode materials, including but not limited to LMFP, LMO, LCO and NMC.

Zn-CD@Eu Ratiometric Fluorescent Probe for the Detection of Dipicolinic Acid, Uric Acid, and Ex Vivo Uric Acid Imaging.

Development of reliable methods for the detection of potential biomarkers is of the utmost importance for an early diagnosis of critical diseases and disorders. In this study, a novel lanthanide-functionalized carbon dot-based fluorescent probe Zn-CD@Eu is reported for the ratiometric detection of dipicolinic acid (DPA) and uric acid (UA). The Zn-CD@Eu nanoprobe was obtained from a simple room-temperature reaction of zinc-doped carbon dots (Zn-CD) and the EDTA-Eu lanthanide complex. Under optimal conditions, a good linear response was obtained for DPA in two concentration ranges of 0-55 and 55-100 μM with a limit of detection of 0.53 and 2.2 μM respectively, which is significantly below the infectious dosage of anthrax (∼55 μM). Furthermore, the Zn-CD@Eu/DPA system was employed for the detection of UA with a detection limit of 0.36 μM in the linear range of 0-100 μM. The fluorescent probe was successfully implemented for determining DPA and UA in human blood serum, sweat, and natural water bodies with considerable recovery rates. In addition, the potential of the nanoprobe for ex vivo visualization of UA was demonstrated in fruit fly (Drosophila melanogaster) as a model organism.

Dicationic ionic liquid immobilized on polystyrene as an acidic, reusable, and efficient heterogeneous organocatalyst in organic transformations

Supported ionic liquids onto solid catalysts are among the most popular catalysts in chemical reactions with several unique advantages. However, the harsh reaction conditions, long reaction times, low product yields, and tedious work-up, are still the challenges for its application. A novel polystyrene-modified dicationic ion liquid [PS-(Im)2-SO3H] was synthesized through the reaction of chloromethyl polystyrene with imidazole, 1,4-dichlorobutane and 1,3-propanesultone. Its structure was characterized and confirmed using Fourier Transform Infrared spectroscopy (FT-IR), Thermogravimetric analysis (TGA), X-ray diffraction (XRD), Dynamic Light Scattering (DLS), Scanning Electron Micrograph (SEM), Energy Dispersive Spectroscopy (EDS), and Elemental analyses. This polymer-supported dicationic ion liquid was used as an acidic heterogeneous catalyst for the synthesis of xanthene derivatives through condensation of aldehydes, dimedone, and β-naphthol. The products were obtained in high yields (88–97 %) at room temperature and short reaction time in ethanol as a green solvent. The reaction mixture was easily filtered to isolate the heterogeneous catalyst, which could be reused for at least eight cycles without any significant activity loss.

Metal-Free Bisamidation of N-Tosylhydrazones with Carboxylic Acids Promoted by Tetrabutylammonium Iodide and tert-Butyl Hydroperoxide.

A versatile reaction between N-tosylhydrazones and carboxylic acids to access bisamides is reported. This metal-free, room-temperature reaction was catalyzed by TBAI, while TBHP served as the oxidant. Broad substrate scope and good functional group tolerance are the key features of the strategy. Subsequent intramolecular N-arylation of suitably substituted bisamides readily afforded functionalized 3-indazolones.

Temperature Dependence of the Ring Opening of Cyclopropene Imines on Thorium Metallocenes.

The reactions of two highly strained cyclopropenimine ligands L1H and L2H (L1H = N1,N1,N2,N2-tetraisopropyl-3-iminocycloprop-1-ene-1,2-diamine, L2H = N1,N1,N2,N2-tetracyclohexyl-3-iminocycloprop-1-ene-1,2-diamine) with three thorium precursors Cp*2ThCl2, Cp*2Th(Cl)(CH3), and Cp*2Th(CH3)2 were studied. At -20 °C, L1H and L2H react with Cp*2ThCl2 to form Th1 (Th1 = Cp*2ThCl2(L1H)) and Th2 (Th2 = Cp*2ThCl2(L2H)), respectively, where the neutral ligand coordinates to the thorium metal center. Coordination of the ligand to the thorium metal center introduces aromaticity at the cyclopropene ring of the ligand. Reaction at room temperature results in the ring opening of the ligand to form Th3 (Th3 = Cp*2ThCl2((Z)-2,3-bis(diisopropylamino)acrylonitrile) and Th4 (Th4 = Cp*2ThCl2((Z)-2,3-bis(dicyclohexylamino)acrylonitrile), where the cyclopropenimine converts into a nitrile and coordinates to the thorium metal center. Reaction of L1H and L2H with Cp*2Th(Cl)(CH3) and/or Cp*2Th(CH3)2 at -20 °C results in a rapid methanolysis reaction and forms Cp*2Th(L1/L2)(CH3/Cl)-type complexes Th5 (Th5 = Cp*2Th(L1)(CH3)), Th6 (Th6 = Cp*2Th(L2)(CH3), Th7 (Th7 = Cp*2Th(L1)(Cl), and Th8 (Th8 = Cp*2Th(L2)(Cl). On the other hand, at room temperature, these reactions result in a ring opening of the ligand. Room-temperature reaction of L1H and L2H with Cp*2Th(CH3)2 results in Th9 (Th9 = Cp*2Th(CH3)((Z)-3-imino-N1,N1,N2,N2-tetraisopropylbut-1-ene-1,2-diamine) and Th10 (Th10 = Cp*2Th(CH3)((Z)-3-imino-N1,N1,N2,N2-tetracyclohexylbut-1-ene-1,2-diamine). Similarly, at room temperature, L1H and L2H react with Cp*2Th(Cl)(CH3) to form Th11 (Th11 = Cp*2Th(Cl)((Z)-3-imino- N1,N1,N2,N2-tetraisopropylbut-1-ene-1,2-diamine) and Th12 (Th12 = Cp*2Th(Cl)((Z)-3-imino-N1,N1,N2,N2-tetracyclohexylbut-1-ene-1,2-diamine). The ring-opening reaction is assisted by the nucleophilic attack of the thorium-coordinated methyl group to the highly strained cyclopropene imine carbon.

Room-temperature olefin epoxidation reaction by two 2D cobalt metal-organic complexes under O2 atmosphere: coordination and structural regulation

Room-temperature olefin epoxidation reaction by two 2D cobalt metal-organic complexes under O2 atmosphere: coordination and structural regulation