Amino Groups Research Articles

Bilateral Embedded Anchoring via Tailored Polymer Brush for Large-Area Air-Processed Blue Light-Emitting Diodes.

Perovskite light-emitting diodes (PeLEDs) that can be air-processed promises the development of displaying optoelectronic device, while is challenged by technical difficulty on both the active layer and hole transport layer (HTL) caused by the unavoidable humidity interference. Here, we propose and validate that, planting the polymer brush with tailored functional groups in inorganic HTL, provides unique bilateral embedded anchoring that is capable of simultaneously addressing the n phases crystallization rates in the active layer as well as the deteriorated particulate surface defects in HTL. Exemplified by zwitterionic polyethyleneimine-sulfonate (PEIS) in present study, its implanting in NiOx HTL offers abundant nuclei sites of amino and sulfonate groups that balance the growth rate of different n phases in quasi-2D perovskite films. Moreover, the PEIS effectively nailed the interfacial contact between perovskite and NiOx, and reduced the particulate surface defects in HTL, leading to the enhanced PLQY and stability of large-area blue perovskite film in ambient air. By virtue of these merits, present work achieves the first demonstration of the air-processed blue PeLEDs in large emitting area of 1.0 cm2 with peak external quantum efficiency (EQE) of 2.09 %, which is comparable to the similar pure-bromide blue PeLEDs fabricated in glovebox.

Facile synthesis of azines by carboxylic acid esters as catalyst and facilitation of intersystem crossing (ISC) in azines by azine chromophore

Development of new organic synthetic methods fascinating the researchers which facilitating the increasing demands of the modern society, environmental friendly with high efficiency and low cost. The introduction of chromophores in an organic molecules facilitating intersystem crossing (ISC) to harvest both singlet and triplet excitons is also currently demanding field. We report a facile synthesis of symmetrical azines from carbonyl compounds and hydrazine hydrate with carboxylic acid esters as catalyst in methanol. This reaction presents a condensation of primary amino groups in hydrazine hydrate and carbonyl compounds took place simultaneously in a very short refluxing time. The prepared azines 1–10 were structurally analysed by various analytical techniques such as LC-MS1, H NMR13, C NMR, UV-Vis, FTIR and single crystal X-ray diffraction. Photoluminescence properties of prepared azines were recorded in CCl4 at 1 × 10−3 M and excitation range from 329 to 362 nm. The photoluminescence analysis results revealed that compounds 1–10 (except 8) were showed delayed fluorescence and 8 was showed fluorescence property. The photophysical properties of compounds 1–10 such as electron density and band gap energies was calculated by density function theory. This results revealed that the intra-molecular charge transfer occurs within the azines. The azine function in the azines enabling intersystem crossing hence, it is showing phosphorescence.

Enhancing gene delivery efficiency with amphiphilic chitosan modified by myristic acid and tertiary amino groups

The aim of this study is to synthesize new amphiphilic chitosan containing myristic acid as the hydrophobic tail and tertiary amine groups as the hydrophilic head and to evaluate the gene delivery efficiency. In this context, the primary amine groups of chitosan were first modified with myristic acid (Chi-M), followed by the modification of the methylol groups with 3-dimethylamino-1-propyl chloride hydrochloride. The chemical characterization of this chitosan formulation (Chi-MA) was determined using nuclear magnetic resonance (NMR), Fourier-transform infrared spectroscopy (FTIR) analysis and gel permeation chromatography-size exclusion chromatography. Chi-MA nanoparticles were prepared via ionic gelation, and particle size, polydispersity and zeta potential were determined. The nanoparticles were evaluated for their proton buffering capacity and gene complexing capacity. Additionally, the cytotoxicity of Chi-MA on HEK293T cells was determined via MTT assay, and the transfection efficiency of Chi-MA was analyzed by a flow cytometer. The results indicate a significant increase in gene complexing capacity (8-fold) and nanoparticle formation ability of Chi-MA compared to other chitosan formulations. Chi-MA nanoparticles showed no toxicity against HEK293T cells and exhibited the highest transfection efficiency with significantly lower nanoparticle: gene ratios compared to previous studies. These findings demonstrate the effective use of amphiphilic Chi-MA as a gene carrier.

Substituent Regulating Porphyrin Derivatives for Efficient Photocatalytic Hydrogen Evolution

AbstractPorphyrin and its derivatives have been seen as a type of potential organic photocatalyst for photocatalytic hydrogen evolution. Substituent regulation as a simple method can effectively regulate the photoelectric characteristic of organic semiconductors. Herein, we designed three porphyrin derivatives attached with different substituents (PP‐NH2, PP‐OH and PP‐COOH). Through a facile substituent optimization strategy, the photoelectric properties of these porphyrin derivatives show an obvious difference, which leads an optimized photocatalytic hydrogen evolution efficiency. The porphyrin derivative with carboxyl presents a reduced impedance, and a better charge separation. Compared to the amino group, PP‐COOH with carboxyl, achieved a high hydrogen evolution rate of 2.20 mmol g−1 h−1 (over 20 times than that of PP‐NH2). Moreover, enhanced stability was observed in PP‐COOH rather than PP‐OH, because of the lower HOMO energy level. And the ionization of carboxyl in water negatively charges the porphyrin derivatives and forms a relatively stable sol. This result further increases the operation stability of PP‐COOH, during photocatalytic hydrogen evolution. This study presents a promising design strategy for long‐lifetime photocatalysts for hydrogen evolution.

Zr-MOF-based substrate with inherent internal standards facilitates reliable SERS analysis of sulfonamide antibiotics

A multifunctional structure comprising gold nanoparticles immobilized within a zirconium-based metal-organic framework (AuNPs/Zr-MOF) was systematically designed. With the capabilities of analyte enrichment, Raman signal enhancement and internal standard calibration, the as-prepared AuNPs/Zr-MOF substrates demonstrate the outstanding SERS sensing performance toward the representative sulfonamide antibiotics (SAs), sulfadiazine, sulfamerazine, sulfamethazine and sulfaquinoxaline. For the first time, these four SAs are detected by SERS in real honey samples at levels of 2.8 ∼ 5.2 ng·g−1 within 10 min. The extensive π-bond conjugated system of Zr-MOF significantly enhances the concentration of SAs through π-π interactions. The entrapped SAs are adsorbed perpendicularly onto the surface of Au via coordinated interactions between Au and two oxygen atoms, or between Au and the terminal amino group. To achieve reliable quantitative analysis, the inherent vibration of the Zr-MOF structure was used as an internal standard label. Combined with a simple clean-up protocol, the established SERE sensing method is superior to conventional methods in terms of time, while achieving the impressive sensitivity. This study presents a robust SERS-based approach for the rapid detection and monitoring of multiple analytes.

Self-aggregation and microhydration mechanisms of monoethanolamine: Far-infrared identification of large-amplitude hydrogen bond libration.

The strong tendency for self-aggregation together with an intriguing mechanism for the microhydration of monoethanolamine (MEA) have been explored by low-temperature far-infrared cluster spectroscopy in doped neon "quantum" matrices at 4K complemented by high-level quantum chemical modeling. In addition to the assignment of new mid-infrared perturbed intramolecular transitions, a distinct far-infrared transition is unambiguously assigned to the concerted large-amplitude hydrogen bond librational motion of the MEA homodimer. This observation confirms a global "head-to-head" intermolecular potential energy minimum associated with the formation of a compact doubly intermolecular OH⋯N hydrogen-bonded cyclic structure, where both monomeric intramolecular OH⋯N hydrogen bonds are broken upon complexation. By means of relative mixing ratio dependencies, dedicated annealing procedures, and selective complexation between MEA and isotopic H216O and H218O samples, distinct far-infrared transitions associated with large-amplitude intra-molecular hindered OH torsional motion and inter-molecular H2O librational (hindered c-type overall rotational) motion of the MEA monohydrate are furthermore assigned unambiguously for the first time. These spectroscopic observations reveal an intriguing metastable conformation, where H2O acts as a OH⋯O hydrogen bond donor to the hydroxy group instead of the amino group of MEA upon microhydration in the cryogenic neon environment, where the microhydration strengthens the intramolecular OH⋯N hydrogen bond of MEA due to hydrogen bond cooperativity.

Dual-active-group co-modification of BiOBr for boosting photocatalytic CO2 reduction coupled with ciprofloxacin oxidation

Coupling CO2 photoreduction with ciprofloxacin (CIP) oxidation presents a promising strategy for achieving not only the complete utilization of photoexcited carriers but also the win–win goals of energy conversion and environmental remediation. In this study, we utilized an aminated BiOBr catalyst with surface hydroxyl groups (NH2/BOB–OH) for efficient photocatalytic CO2 reduction coupled with CIP oxidation. In this process, hydroxyl (OH) and amino groups (NH2) adsorbed and activated CIP (an organic pollutant) and CO2 molecules, respectively, promoting the overall photocatalytic redox activity. Remarkably, 0.5NH2/BOB–OH exhibited excellent photocatalytic redox performance for CO2 reduction coupled with CIP oxidation, with the CO yield and CIP degradation efficiency being 6.85 and 1.08 times higher, respectively, than those achieved using BiOBr without any active groups. Moreover, a series of in situ experimental characterizations and theoretical simulations revealed that these two opposing active groups not only accelerated carrier separation but also boosted the surface reactivity of the catalyst. These findings provide helpful insights into the dual-active-group functionalization of semiconductors, leading to their high photoredox activity for energy conversion along with environmental remediation.

In situ synthesis of nano-CeO2 and chitosan composite

Nanosized cerium oxide (CeO2) particles were prepared by co-precipitation method using chitosan as a template, cerium (III) nitrate and cerium (IV) sulfate as starting materials and aqueous ammonia solution as a precipitating agent. XRD data indicate that cerianite with face-centered cubic phase is formed in the reaction systems. The size of the coherent scattering regions is about 3 nm or less. FTIR spectroscopy data indicate the interaction of polymer molecules with the inorganic component. The shift of absorption bands related to N-H bonds for composites with Ce(III) and Ce(IV) compared to chitosan indicates the interaction of amino groups with CeO2 particles. The application of chitosan as a matrix for the synthesis of CeO2 nanoparticles showed that this approach is more economical and easier to produce nanomaterials for various applications.

Construction of “organic–inorganic” hierarchical structure of carbon fibers and the effect on the properties of epoxy composites

AbstractThe demand for epoxy (EP) in semiconductor, aerospace, and other applications is currently on the rise. However, pure epoxy is difficult to meet these requirements, such as low thermal conductivity and poor toughness. Therefore, in this paper, sulfonamides (SAs) and core‐shell silica (SLC‐SiO2) were grafted onto the surface of short carbon fibers (SCF) with sizes of 0.1–6 mm by the chemical grafting method. As a result, the surface activity of SCF was improved and the interfacial properties of the EP composites were enhanced. The interfacial compatibility of SCF grafted with SAs and SLC‐SiO2 in EP is greatly improved, resulting in stronger mechanical interlocking and chemical bonding ability between EP and SCF. The results showed that when the content of SCF@SAs@SLC‐SiO2/EP composites reached 0.3 wt% of SCF@SAs@SLC‐SiO2, the impact and tensile strengths were increased from 12.15 kJ·m−2 and 43.4 MPa to 16.93 kJ·m−2 and 74.97 MPa compared with the pure epoxy, which were improved 39.3% and 72.7%. In addition, the thermal conductivity of SCF@SAs@SLC‐SiO2/EP composites was also improved by 12.5% from 0.205 W·(m·K)−1 to 0.2306 W·(m·K)−1 compared with the pure EP. This is due to improved chemical interactions and mechanical interlocking at the fiber‐epoxy interface. This study provides a new method for the preparation of high‐performance SCF/EP composites.Highlights The amino group of sulfonamides was grafted with short carbon fiber to increase the surface active group of short carbon fiber. Sulfonamides react with carboxyl groups on the surface of core‐shell silica to form an “organic–inorganic” structure. Improve the surface roughness of short carbon fiber, and make it evenly dispersed in epoxy resin, so as to improve the performance of epoxy composite materials.

Adsorption effect for removing fluoride with species of nitrogen by using La-BDC-NH2/C3N4: Experiments and mechanism

Fluoride contamination has emerged as a significant global environmental concern, with prolonged consumption of fluoride-rich groundwater being a primary contributor to fluorosis. Nitrogen sites play an important role in the process of fluoride removal, but the influence of different nitrogen species on fluoride adsorption has not been clearly clarified. In this study, a lanthanide organic framework adsorbent La-MOF-NH2 was prepared by solvothermal method, and a new adsorbent La-MOF-NH2@g-C3N4 was synthesized by adding g-C3N4 rich in various nitrogen sources. The effects of adsorbent dosage, pH, temperature and co-existing anions on the adsorption of fluorine were systematically studied. Optimal conditions were identified at a dosage of 2 g/L and a pH of 3, achieving theoretical maximum adsorption capacities of 219.4406 mg/g and 63.1401 mg/g, respectively. The results of five regeneration experiments shown that La-MOF-NH2 and La-MOF-NH2@g-C3N4 have strong recovery capacity. According to the adsorption isotherm and kinetic model, the adsorption mechanism of fluoride ions is mainly hydrogen bonding and chemisorption. In addition, through the experimental characterization and mechanism study, it was proved that amino group > pyridinic nitrogen > graphitic nitrogen. It provides a good guide for designing adsorbents containing nitrogen sites.

Investigation on CO2 capture performance of low-viscosity diamine non-aqueous absorbents with N-methyldiethanolamine regulation

In recent years, non-aqueous absorbents have attracted increasing attention due to their ability of significantly reducing sensible and latent heats in regeneration processes compared to conventional organic amine aqueous solution. But high viscosity of non-aqueous absorbents after CO2 absorption saturation became an obstacle to their industrial application. Here, a novel low-viscosity diamine non-aqueous absorbent for high-efficiency CO2 capture was proposed, in which N-methyldiethanolamine (MDEA) with steric hindrance effect was introduced as a regulator and dimethyl sulfoxide (DMSO) as a cosolvent. The effects of MDEA on CO2 capture performance of various non-aqueous absorbents and its regulation mechanism on CO2 absorbent viscosity were investigated systematically. Experimental results showed that when 25 wt% 2-(2-aminoethylamino)ethanol (AEEA) was screened as main CO2 absorption component, AEEA/MDEA/DMSO non-aqueous absorbent exhibited a high CO2 absorption capacity of 2.55 mol/kg and a fast CO2 absorption rate. Based on further mass fraction optimisation, it was found that the lowest viscosity of non-aqueous absorbents after CO2 absorption was 13.12 mPa s and the highest CO2 regeneration reached 93.5 % with AEEA and MDEA were 17.5 wt% and 12.5 wt%, respectively. 13C NMR tests showed that two characteristic peaks of carboxylated carbon appeared in CO2 products, which indicated that both amino groups on AEEA molecule were involved in CO2 absorption reaction. DFT calculations indicated that hydrogen bonding strength between MDEA and CO2 products was relatively lower than that of AEEA and CO2 products, which favored reducing absorbent saturation viscosity significantly. Thermodynamic analysis revealed that total regeneration energy consumption for 17.5 wt% AEEA/12.5 wt% MDEA/70 wt% DMSO non-aqueous absorbent was 1.72 GJ/t CO2, which was 53 % lower than that of MEA aqueous solution.

Preparation and oxidative desulfurization performances of modified SBA-15 supported polyacid metal oxolates

In this study, eight composite catalysts were prepared by loading (CTAB)3H3[PW9V3O40] (active components) onto amino-functionalized mesoporous titanium silicate Ti-SBA-15(supports). In order to study the effects of different Ti contents and different active components on the catalytic performances of the catalysts, 30 %(CTAB)3H3[PW9V3O40]/NH2–Ti-SBA-X (X = 0, 25, 50, 75, 100) and X%(CTAB)3H3[PW9V3O40]/NH2–Ti-SBA-50 (X = 20, 40, 50) were obtained and characterized. The oxidative desulfurization performances of the composite catalysts were explored. It was found that catalyst 40 %(CTAB)3H3[PW9V3O40]/NH2–Ti-SBA-50 exhibits the optimal oxidative desulfurization performance. This is because the incorporation of SBA-15 with an appropriate amount of Ti (n(Si)/n(Ti) = 50) can improve the acidity and stability of mesoporous silica. The successful substitution of CTAB (n(CTAB)/n(H6PW9V3O40) = 3) in the active component can reduce the mass transfer resistance and speed up the reaction rate. 3-Aminopropyltriethyl silane (APTES) acts as a silane coupling agent to graft amino groups onto mesoporous molecular sieve SBA-15, which can enhance the interaction between heteropolyacids and carriers. Under the synergistic effect of the active component and the support, the total removal rate of the optimal catalyst with a total concentration of 1000 ppm sulfur compounds in the simulated fuel was 94.44 %. After four cycles, the total desulfurization rate of the catalyst can reach 91.28 %.

Combining Mesoporous Bioactive Glass Nanoparticles (MBGNs) with Essential Oils to Tackle Bacterial Infection and Oxidative Stress for Bone Regeneration Applications.

Bacterial infectious diseases remain one of the significant challenges in the field of bone regeneration applications. Despite the development of new antibiotics, their improper administration has led to the development of multiresistant bacterial strains. In this study, we proposed a novel approach to tackle this problem by loading clove oil (CLV), a natural antibacterial compound, into amino-functionalized mesoporous bioactive glass nanoparticles (MBGNs). The scanning electron microscopy images (SEM) revealed that amino-functionalization and CLV loading did not affect the shape and size of the MBGNs. The successful grafting of the amino groups on the MBGNs' surface and the presence of CLV in the material were confirmed by attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy and zeta potential measurements. The increased CLV concentration led to a higher loading capacity, encapsulation efficiency, and antioxidant activity. The in vitro CLV release profile exhibited an initial burst release, followed by a controlled release over 14 days. The loading of CLV into MBGNs led to a stronger antibacterial effect against E. coli and S. aureus, while MG-63 osteoblast-like cell viability was enhanced with no morphological changes compared to the control group. In conclusion, the CLV-MBGNs nanocarriers showed promising properties in vitro as novel drug delivery systems, exploiting essential oils for treating bone infections and oxidative stress.

Modulating the Amine-CO2 Interaction Strength: Toward Efficient Carbon Capture.

This study contributes to a comprehensive understanding of the interactions between CO2 and amines at the molecular level by exploring the rotational spectra of binary complexes between CO2 and eight different amines through pulsed-jet Fourier transform microwave spectroscopy and quantum chemical calculations. The findings reveal a consistent pattern in which CO2 is bonded to the amino group, primarily through a C···N tetrel bond, while being supported by C-H···O/C hydrogen bonds. Notably, the binding energies increase from primary through tertiary amines and with increasing chain length of the alkyl groups. These groups are found to enhance the electron density at the amino group significantly, thereby facilitating the formation of stronger C···N tetrel bonds. The insights provided into how the interaction strength is modulated by the geometries of amines are deemed essential for the design of more effective CO2 adsorption materials, thus advancing carbon capture technologies.

PLGA/Ti-Zn as Nanocomposite for Drug Delivery of Oleoresin

Capsicum annuum L. var. “Chile de árbol” combined with poly(lactic-co-glycolic acid) (PLGA) and TiO2-ZnO oxides synthesized at different molar ratios and pH (Ti-Zn A and B 3:1, 1:1, and 1:3) via the sol-gel method was characterized by the Brunauer–Emmett–Teller (BET) method, a UV-Vis spectrophotometer (UV-Vis), Fourier transform infrared spectroscopy (FT-IR), High-Performance Liquid Chromatography (HPLC-DAD), and a release profile through mathematical models to explain its behavior. Furthermore, FTIR revealed the presence of PLGA, TiO2, and ZnO as well as amino group characteristics from oleoresin components, principally alkaloid groups (capsaicin and dihydrocapsaicin), as evidenced by HPLC, to identify the presence of capsaicin and dihydrocapsaicin. The UV-Vis spectra showed a slight hypsochromic shift in the PLGA treatments. The release profile demonstrated a higher controllable release in the PLGA treatments than in the double nanoemulsions. Moreover, it is important to note that the effect of NPs influenced the release profile itself, increasing the release when NPs were synthesized at an acidic pH. Therefore, the TiZnOl/PLGA A characteristics suggest that these results have potential for pharmaceutical (as drug carriers) and medical applications.

Covalent Self-Assembly of Bio-HCP Nanoparticles for Shell-Programmed Encapsulation of Microbial Cells.

Modifying the bacterial surface through grafting functional nanoparticles is a common strategy for programing bacteria. At this moment, the targeted nanoparticles face a dilemma of no multifunctional structure, high toxicity, and weak chemical driving forces, which restrict the broad practical applications. Like a multistage booster of a rocket, we propose a multistage covalent self-assembly strategy to protect, expand, and control the encapsulated shells of microbial cells via biocompatible hyper-cross-linked polymer nanoparticles (Bio-HCP NPs) with internal porosity and surface functional groups. The bacterial surface is enhanced with rich amino groups up to 1010 per cell for specifically grafting nanoparticles. The arming bacteria after first-stage assembly can complete biocatalysis in a highly toxic environment, and as-prepared polymer aggregates (6-20 μm) after third-stage assembly can be accurately counted in an aerosol environment. This nanoparticle encapsulation exhibits strong cell viability from pollutants and specificity from impurity particles, holding promise for various complex application scenarios.

Rational Design of Regenerable Amino-Functionalized Fluorescent Covalent Organic Framework for the Exclusive Detection of Mercury(II).

Goal-oriented development of novel covalent organic frameworks (COFs) to construct a sensing platform for highly toxic mercury (II, Hg2+) is of tremendous significance. Recently, numerous COFs with sulfur-based ligands were developed for Hg2+ monitoring; however, strong binding of Hg2+ by sulfur makes their regeneration very tough. Herein, we designed and developed an amino-functionalized fluorescent COF (COF-NH2) through facile postmodification for Hg2+ detection in which the π-conjugation skeleton is the signal reader and the nitrogen-based side is the highly selective Hg2+ receptor. More importantly, this nitrogen-based receptor permits the reversible binding of Hg2+. As a sensing platform, the outstanding performance of COF-NH2 for Hg2+ detection was reached with respect to high sensitivity with an ultralow detection of 15.3 nM, real-time response with rapid signal change of 10 s, and facile visualization with significant fluorescence color change. Expectedly, COF-NH2 obtained facile recycling which still shows excellent response performance toward Hg2+ after six cycles based on the reversible interaction between amino groups and Hg2+. Our work not only shows an attractive foreground of fluorescent COF for Hg2+ detection but also emphasizes the easy construction of novel COF materials via the rational introduction of metal ligands for the recognition of other metal ions.

Synthesis, structures and Hirshfeld surface analyses of 2-hydroxy-N′-methylacetohydrazide and 2-hydroxy-N-methylacetohydrazide

The structures of the title compounds 2-hydroxy-N′-methylacetohydrazide, 1, and 2-hydroxy-N-methylacetohydrazide, 2, both C3H8N2O2, as regioisomers differ in the position of the methyl group relative to the N atoms in 2-hydroxy-acetohydrazide. In the structure of 1, the 2-hydroxy-acetohydrazide core [OH—C—C(=O)—NH—NH] is almost planar and the methyl group is rotated relative to this plane. As opposed to 1, in the structure of 2 all non-hydrogen atoms lie in the same plane. The hydroxyl and carbonyl groups in structures 1 and 2 are in trans and cis positions, respectively. The methyl amino group and carbonyl group are in the cis position relative to the C—N bond in structure 1, while the amino group and carbonyl group are in the trans position relative to the C—N bond in stucture 2. In the crystal, molecules of 1 are linked by N—H...O and O—H...N intermolecular hydrogen bonds, forming layers parallel to the ab crystallographic plane. A Hirshfeld surface analysis showed that the H...H contacts dominate the crystal packing with a contribution of 55.3%. The contribution of the H...O/O...H interaction is somewhat smaller, amounting to 30.8%. In the crystal, as a result of the intermolecular O—H...O hydrogen bonds, molecules of 2 form dimers, which are linked by N—H...O hydrogen bonds and a three-dimensional supramolecular network The major contributors to the Hirshfeld surface are H...H (58.5%) and H...O/O...H contacts (31.7%).

Preparation of phenol-formaldehyde composite modified with chitosan for the simultaneous removal of antibiotics and heavy metal ions in waters

In current study, a new adsorbent based on aminated phenol-formaldehyde composite was prepared using chitosan as modifier. Various techniques were adopted to characterize the morphology and structure of the prepared adsorbent. Due to the abundant amino groups, the obtained adsorbent presented satisfactory adsorption performance towards fluoroquinolones (FQs) and heavy metal ions (including Cu2+, Cd2+ and Pb2+) by means of multiple forces including electrostatic, H-bonding, π-π stacking interactions (for FQs) and chelating force (for heavy metal ions). Studies about the adsorption kinetics, isotherm and thermodynamics were performed to inspect the adsorption behaviors of studied FQs and heavy metal ions on the new adsorbent. After optimizing the adsorption parameters, the obtained adsorbent were employed to remove FQs, Cu2+, Cd2+ and Pb2+ in various environmental waters. The removal rates for FQs and heavy metal ions were 91.8–98.6 % and 94.4–98.5 %, respectively, which were significantly higher than that obtained on unmodified phenol-formaldehyde resin (20.7–49.0 % for FQs and 35.1–43.0 % for heavy metal ions). At the same time, the adsorbent exhibited good preparation repeatability in different batches, acceptable stability and reusability. The current study well demonstrated the potential application of the new adsorbent in the simultaneous removal of organic and inorganic pollutants from aqueous waters.

Synthesis and DFT investigations of novel 13-(pyrimidin-2-yl)-6H,12H-6,12-epiminodibenzo[b,f][1,5]dioxocine derivatives

Heterocyclic compounds containing nitrogen and oxygen atoms are of great importance and wide applications in the fields of biomedicine and functional materials. In this paper, novel 13-aryl-6H,12H-6,12-epiminodibenzo[b,f][1,5]dioxocines generated from cascade reactions between arylamines and 2-hydroxybenzaldehyde have been explored through both experiments and theoretical calculations. Experimental investigations showed that pyrimidin-2-amine could react with 2-hydroxybenzaldehyde in acetonitrile at 80 °C to afford the desired 13-(pyrimidin-2-yl)-6H,12H-6,12-epiminodibenzo[b,f][1,5]dioxocines with 50 mol % of p-toluenesulfonic acid as catalyst, but aniline reacted with 2-hydroxybenzaldehyde to generate aldimine instead of the target bridged heterocylic compound. Density functional theory (DFT) computations were conducted to investigate the reaction mechanisms of 2-hydroxybenzaldehyde reacting with pyrimidin-2-amine and aniline, respectively. The experimental findings can be reasonably explained by theoretical calculations. Both the experimental explorations and suggested mechanisms indicate that the reactivity of the model reaction is sensitive to the electron density on the amino group of arylamine and the aldehyde group of 2-hydroxybenzaldehyde, which can be finely tuned with the aromatic ring structure and the substituents on it.