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The primary goal of this study is to examine PO 4 3- adsorption from aqueous solutions using zinc-doped carbon dots (Zn-N-CDs) as a new adsorbent and cost-effective technique. Zn-N-CDs were produced through a hydrothermal process and subsequently identified using various techniques. The effect of reaction time, temperature, pH, ionic strength, adsorbent dosage, initial PO 4 3- concentration, and anion competition (NO 3 - , Cl - , HCO 3 - , and SO 4 2- ) on PO 4 3- adsorption using Zn-N-CDs were investigated. The characterization results depicted that Zn-N-CDs have a spherical structure without obvious aggregation and revealed the amorphous nature of carbon dots with many pores. Zn-N-CDs had a high affinity for adsorbing PO 4 3- , reaching equilibrium within 5 minutes. While PO 4 3- adsorption reduced with an increase in temperature, it increased with pH and ionic strength. The optimal conditions for PO 4 3- adsorption were determined to be pH 8, 100 mM KCl as an ionic strength, and 5 g L -1 of Zn-N-CDs. The presence of SO 4 2- and HCO 3 - as competing anions slightly decreased PO 4 3- adsorption. Thermodynamic studies revealed that PO 4 3- adsorption onto Zn-N-CDs was endothermic, spontaneous, and disordered, as evidenced by Δ G ° < 0, Δ H ° > 0, and Δ S ° > 0. The experimental data fit well with a pseudo-second-order kinetic model ( R 2 = 0.999) and the Freundlich isotherm model ( R 2 = 0.9754), signifying that PO 4 3- adsorption onto Zn-N-CDs occurs through multi-layer and chemi-sorption mechanisms. Overall, Zn-N-CDs indicated a great capability to adsorb high concentrations of PO 4 3- across a wide range of pH values, indicating their potential for environmental remediation., Competing Interests: The authors declare no conflict of interest., (This journal is © The Royal Society of Chemistry.)

In this study, Cu(0) nanoparticles supported on organo-modified montmorillonite with benzalkonium chloride (MMT-BAC@Cu(0)) were synthesized and used as an eco-friendly and green heterogeneous catalyst for the synthesis of 5-substituted 1 H -tetrazoles in mild media. The structure of the catalyst was investigated using various techniques including XRD, EDX, ICP, TEM, FE-SEM, and FT-IR. The advantages of availability, low cost, non-toxicity, and biocompatibility of clay were our focus in synthesizing this nanoclay catalyst. The method's advantages include good to excellent product yields, mild conditions, easy work-up, short reaction times, and easy reuse of the nanocatalyst., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (This journal is © The Royal Society of Chemistry.)

In this work, the new trinuclear manganese catalyst defined as Fe 3 O 4 @NFC@NNSM-Mn(iii) was successfully manufactured and fully characterized by different techniques, including FT-IR, XRD, TEM, SEM, EDX, VSM, and ICP analysis. There have been reports of the use of magnetic catalysts for the synthesis of xanthine derivatives. The critical potential interest in the present method include short reaction time, high yields, recyclability of the catalyst, easy workup, and the ability to sustain a variety of functional groups, which give economical as well as ecological rewards. Also, the synthesized catalyst was used as a recyclable trinuclear catalyst in alcohol oxidation reactions at 40 °C. The magnetic catalyst activity of Fe 3 O 4 @NFC@NNSM-Mn(iii) could be attributed to the synergistic effects of the catalyst Fe 3 O 4 @NFC@NNS-Mn(iii) with melamine. Employing a sustainable and safe low temperature, using an eco-friendly solvent, no need to use any additive, and long-term stability and magnetic recyclability of the catalyst for at least six successive runs are the advantages of the current protocol towards green chemistry. This protocol is a benign, environmentally friendly method for heterocycle synthesis., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

Today, due to the developing need for inexpensive catalysts, recyclable magnetic nanocatalysts immobilized on polysaccharides possess many advantages over classical heterogeneous catalysts. However, cellulose has been an appealing material in catalysis science and technology. In this work, by controlling the interaction between the inorganic complexes and the support material, we designed a high activity nanostructured combination of a magnetic nanoparticle Fe 3 O 4 @NFC@Co(ii) terminated complex as a multi-nuclear catalyst. This protocol involves an environment friendly approach using cobalt acetate. The magnetic nanostructure Fe 3 O 4 @NFC@Co(ii) can be used as a novel, green, and a powerful catalyst that demonstrates a short reaction time, high yield and easy procedure for the cascade Knoevenagel-Michael-cyclocondensation reaction for the one-pot synthesis of 4 H -pyrans and pyranopyrazoles. The superparamagnetic nanocomposite could be conveniently separated by using an external magnet. Moreover, the catalyst could be reused at least five times in new reaction runs without a noticeable loss of activity. The prepared catalyst was characterized by FT-IR, XRD, VSM, FESEM, EDAX, TEM, ICP, and TGA techniques. The experiments were achieved with good yields and implied that the catalytic method was effective and convenient for heterocyclic synthesis., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

The Fe 3 O 4 @NFC-ImSalophCu catalyst was used as a highly stable, reusable, active, green catalyst for the synthesis of 1,2,3-triazoles via one-pot three-component reaction of phenacyl bromides, sodium azide and alkynes. A Cu(ii)-Schiff base complex containing an imidazolium ionic phase was prepared and decorated on core shell Fe 3 O 4 @NFC magnetic nanoparticles (Fe 3 O 4 @NFC-ImSalophCu) and was used as an efficient catalyst. The heterogeneous catalyst was characterized by FT-IR spectroscopy, FE-SEM, TEM, XRD spectroscopy, EDX spectroscopy, VSM, and ICP spectroscopy. This catalyst shows the dual function of the metal sites and imidazolium moieties. The catalytic system mentioned above also showed excellent activity in the synthesis of bis 1,4-disubstituted 1,2,3-triazoles. Moreover, the catalyst could be recycled and reused for four cycles without any decrease in its catalytic activity., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

We studied the potential application of an efficient, reusable, and easily recoverable catalyst of dendritic fibrous nanosilica (DFNS)-supported platinum(ii) complexes (DFNS/Pt(ii) NPs) to form cyclic carbonates in the presence of epoxides by converting carbon dioxide. Cyclic carbonates from epoxides and carbon dioxide is proposed as the most appropriate way to synthesis this C1 building block. We performed FE-SEM, TEM, TGA, BET, VSM, and ICP-MS to thoroughly characterize DFNS/Pt(ii) NPs., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

The kinetic and mechanism evaluations of the formation of cyclic carbonates by carbonyl-stabilized phosphonium ylides as an efficient and new class of organocatalysts are the main purposes of this research. Recently, it has been reported that tetraarylphosphonium salts play the role of organocatalysts in carbon dioxide conversion to cyclic carbonates. However, in this research, the oxygen atom of the carbonyl-stabilized phosphonium ylides was treated as the nucleophilic atom for the carbon dioxide activation. Two probable mechanisms were considered and analyzed by the energetic span model. The kinetic behavior of the carbonyl-stabilized phosphonium ylides in the carbon dioxide or ethylene oxide activation was justified by the molecular electrostatic potential (ESP) analysis at the nuclear position. However, it was confirmed that the activation strain model (ASM) was a more efficient tool in explaining the kinetic behaviors in the carbon dioxide or ethylene oxide activation. A change in the ESP value of the donor-acceptor interacting system (ΔΔVn) and distortion energy at the transition states (ΔEstrain(ζ)) were the outcomes of the ESP and ASM models, respectively, which showed a linear correlation. The electron localization function (ELF) concept was used to justify the kinetic behavior of the second step of the preferred mechanism, revealing that the electron-donating/withdrawing groups substituted on the organocatalysts have a remarkable effect on the electron density of the involved basin at the transition states. On the basis of different analyses, it was proposed that carbonyl-stabilized phosphonium ylides having electron-donating substituents are the best candidates for carbon dioxide conversion to cyclic carbonates.

In the current study, an inexpensive solid-state mechanochemical technique is proposed for the in situ synthesis of nanostructured aluminum nitride (AlN) and carbon nanotubes (CNTs). The CNTs and nitrogen-doped CNTs are synthesized through a novel bottom-up milling approach in which melamine as the solid source of both carbon and nitrogen is milled with aluminum. However, the efficiency of CNT formation remarkably enhances when the milled powder is exposed to a subsequent heat treatment. The effect of various parameters such as milling media, aluminum-to-melamine molar ratio (Al/M), milling time and subsequent heating temperature on the yield and formation mechanism of the produced CNTs are assessed. A detailed characterization of the final products reveals that small amorphous carbon nitride domains resulting from polymerization of melamine molecules at the intermediate stages of milling are responsible for the synthesis of CNTs either during the milling or subsequent heat treatment processes.

Nowadays, the development of highly efficient routes for the low cost synthesis of nitrides is greatly growing. Mechanochemical synthesis is one of those promising techniques which is conventionally employed for the synthesis of nitrides by long term milling of metallic elements under a pressurized N 2 or NH 3 atmosphere (A. Calka and J. I. Nikolov, Nanostruct. Mater., 1995, 6, 409-412). In the present study, we describe a versatile, room-temperature and low-cost mechanochemical process for the synthesis of nanostructured metal nitrides (MNs), carbonitrides (MCNs) and carbon nitride (CN x ). Based on this technique, melamine as a solid nitrogen-containing organic compound (SNCOC) is ball milled with four different metal powders (Al, Ti, Cr and V) to produce nanostructured AlN, TiC x N 1-x , CrC x N 1-x , and VC x N 1-x (x ∼ 0.05). Both theoretical and experimental techniques are implemented to determine the reaction intermediates, products, by-products and finally, the mechanism underling this synthetic route. According to the results, melamine is polymerized in the presence of metallic elements at intermediate stages of the milling process, leading to the formation of a carbon nitride network. The CN x phase subsequently reacts with the metallic precursors to form MN, MCN or even MCN-CN x nano-composites depending on the defect formation energy and thermodynamic stability of the corresponding metal nitride, carbide and C/N co-doped structures.

Polyethylenimine (PEI) is a widely used non-viral vector for DNA delivery. One major obstacle of higher molecular weight PEIs is the increased cytotoxicity despite the improved transfection efficiency and numerous chemical modifications that have been reported to overcome this problem. Carbon nanotubes (CNT) are carbon nanomaterials capable of penetrating into cell membranes with no cytotoxic effects. Covalent and noncovalent functionalization methods have been used to improve their solubility in aqueous media. The idea of conjugating PEIs and CNT through different chemical bonds and linkers seems promising as it may result in highly effective carriers due to combination of the transfection ability of PEI with cell internalization of CNT. In this study, six different water-soluble PEI conjugates of single-walled carbon nanotubes (SWNTs) were prepared by grafting PEI with one of three molecular weights (1.8, 10 and 25 kDa) through succinate as a linker which refers to "an organic moiety through which a SWNT is conjugated to PEI." The succinate linker was introduced to the surface of SWNTs through two different chemical strategies: a) ester and b) acyl linkages. The resulting SWNT-PEI vectors were characterized by IR spectroscopy, thermogravimetric analysis (TGA) and SEM imaging. All synthesized carriers were evaluated and compared for their cytotoxicity and transfection efficiency in murine neuroblastoma cells as polyplexes with plasmid DNA for luciferase and green fluorescent protein (GFP). The most efficient carriers were prepared by attaching PEI with the lowest molecular weight (1.8 kDa) through acyl linkage, which gave a transfection efficiency 190-fold greater than that of the corresponding free PEI. Transfection efficiency was the highest in polyplexes prepared with acyl-linked conjugates in all the plasmid/vector ratios studied.