Pyridine Nitrogen Research Articles

The Effect of Nitrogen Functional Groups on Pb0, PbO, and PbCl2 Adsorption over a Carbonaceous Surface.

Lead (Pb) pollution, especially from the incineration of municipal solid waste (MSW), poses a significant threat to the environment. Among all the effective methods, activated carbon (AC) injection serves as an effective approach for lead removal from flue gas, while the modification of ACs emerges as a crucial pathway for enhancing Pb adsorption capacities. Density functional theory (DFT) is employed in this study to investigate the mechanisms underlying the enhanced adsorption of Pb species (Pb0, PbO, and PbCl2) on nitrogen-functionalized carbonaceous surfaces. The results show that nitrogen-containing groups substantially enhance lead adsorption capacity, with adsorption energies ranging from -526.18 to -288.31 kJ/mol on nitrogen-decorated carbonaceous surfaces, much higher than those on unmodified surfaces (-310.35 to -260.96 kJ/mol). Additionally, electrostatic potential and density-of-states analyses evidence that pyridinic nitrogen atoms remarkably expand charge distribution and strengthen orbital hybridization, thereby augmenting lead capture. This research elucidates the role of nitrogen-containing functional groups in lead adsorption, offering valuable insights for the development of highly efficient biomass-derived activated carbon sorbents for lead removal.

Development of Dual N, S‐Heteroatom Doped Hollow Carbon Spheres as an Alternative Electrocatalyst for Oxygen Reduction Reaction in Alkaline Medium

AbstractHollow heteroatom‐doped mesoporous carbons were found to be an efficient non‐noble metal catalyst to enhance the oxygen reduction reaction (ORR) in fuel cells. Here, we use dopamine hydrochloride (DHC) and dibenzyl disulfide (DBS) as the nitrogen and sulfur precursors to infiltrate N and S into the HCS in a single‐step process. Dibenzyl disulfide is less explored in literature as a sulfur dopant. Due to its high sulfur content and high boiling point, dibenzyl disulfide acts as an excellent sulfur dopant and can withstand the carbonization process. Among them, NSMHCS‐0.2 obtained by adding 0.2 g of dibenzyl disulfide at 31 h intervals to the polydopamine (PDA) loaded silica leads to the ideal N, S dual hetero‐atom doping in NSMHCS. Notably, it has a high shell thickness (45 nm), high BET surface area (637 m2 g−1), high pyridinic nitrogen (13.54 %), and thiophene sulfur (89.8 %) concentration. Such property tuning paved the way to reach a high positive onset potential (0.86 V vs RHE) and a limiting current density of 3.64 mA cm−2 at 0.4 V vs RHE. Additionally, NSMHCS‐0.2 has shown superior methanol tolerance and strong electrochemical stability when compared to Pt/C 20 %.

The Impact of ortho-substituents on Bonding in Silver(I) and Halogen(I) Complexes of 2-Mono- and 2,6-Disubstituted Pyridines: An In-Depth Experimental and Theoretical Study.

The coordination nature of 2-mono- and 2,6-disubstituted pyridines with electron-withdrawing halogen and electron-donating methyl groups for [N-X-N]+ (X=I, Br) complexations have been studied using 15 N NMR, X-ray crystallography, and Density Functional Theory (DFT) calculations. The 15 N NMR chemical shifts reveal iodine(I) and bromine(I) prefer to form complexes with 2-substituted pyridines and only 2,6-dimethylpyridine. The crystalline halogen(I) complexes of 2-substituted pyridines were characterized by using X-ray diffraction analysis, but 2,6-dihalopyridines were unable to form stable crystalline halogen(I) complexes due to the lower nucleophilicity of the pyridinic nitrogen. In contrast, the halogen(I) complexes of 2,6-dimethylpyridine, which has a more basic nitrogen, are characterized by X-crystallography, which complements the 15 N NMR studies. DFT calculations reveal that the bond energies for iodine(I) complexes vary between -291 and -351 kJ mol-1 and for bromine between -370 and -427 kJ mol-1 . The bond energies of halogen(I) complexes of 2-halopyridines with more nucleophilic nitrogen are 66-76 kJ mol-1 larger than those of analogous 2,6-dihalopyridines with less nucleophilic nitrogen. The experimental and DFT results show that the electronic influence of ortho-halogen substituents on pyridinic nitrogen leads to a completely different preference for the coordination bonding of halogen(I) ions, providing new insights into bonding in halogen(I) chemistry.

Colorimetric detection of alkaline phosphatase based on the off-on effect of light-responsive oxidase mimicking activity of covalent organic framework (Cu-TpBpy-COF) under near-neutral condition.

A colorimetric strategy has beendeveloped for the detection of alkaline phosphatase (ALP) activity based on the off-on effect of the catalytic activity of light-responsive oxidase mimics covalent organic framework (Cu-TpBpy-COF) in near-neutral condition. Cu-TpBpy-COF can effectively catalyze the oxidation of the colorless substrate 3,3',5,5'-tetramethylbenzidine (TMB) by oxygen to form a blue oxidized product (oxTMB) with an absorption peak at 652 nm. Cu2+ is the active center of Cu-TpBpy-COF and pyrophosphate (PPi) can form a complex with Cu2+ to weaken the catalytic activity of Cu-TpBpy-COF. In the presence of ALP, PPi is hydrolyzed into orthophosphates (Pi) with low affinity to Cu2+, thus resulting in absorbance restoration. The absorbance at 652 nm is related to ALP activity in the linear range 10-150 U·L-1 with a detection limit of 7.17 U·L-1. The recoveries of ALP in serum samples are in the range 94.7~107.0% with relative standard deviations (RSD) lower than 5%. The decisive role of Cu2+ on the enhancing catalytic activities of Cu-TpBpy-COF in neutral condition was verified by TpBpy-COF and TpBD-COF as controls, in which the main difference between them is that TpBpy-COF contains pyridine nitrogen. Upon Cu2+ modification, Cu-TpBpy-COF has better catalytic activity than TpBpy-COF in a broader pH range because of the in situ generation of Cu+ under irradiation.

Synthesis and Twin Polymerization of Si(OCH2py)4 for Nitrogen‐containing Carbon Materials

AbstractThe synthesis and twin polymerization (TP) of Si(OCH2py)4 (3 a, py=2‐cC5H4N; 3 b, py=3‐cC5H4N; 3 c, py=4‐cC5H4N) is discussed. The solid state structures of 3 b, c were confirmed by single‐crystal X‐ray crystallography showing non‐conventional H‐bonding, forming 2D chains (3 b) or 3D networks (3 c). Thermally induced TP of 3 a–c and their simultaneous polymerization with 2,2‘‐spiro‐bi[4H‐1,3,2‐benzodioxasiline] (4) is described. The resulting hybrid materials were characterized by 1H, 13C{1H}, and 29Si{1H} CP MAS NMR spectroscopy confirming the transformation of the SiOCH2 moieties into CH2 groups enabling the formation of the respective polymers. These results were supported by HAADF‐STEM studies, displaying micro‐structuring. Nitrogen‐containing porous carbon materials C_1–C_3 show surface areas of 1300 and 1700 m2 g−1, large pore volumes between 0.6–1.2 cm3 g−1, and nitrogen contents of up to 3.1 at‐%. X‐ray photoemission spectroscopy reveal that pyrrolic, pyridine, and pyridone nitrogen atoms are present. If equimolar amounts of 3 a–c and 4 are simultaneously polymerized in the presence of [Pd(OAc)2] (5), then the Pd nanoparticle‐decorated material Pd@C_3 (900 m2 g−1) was obtained, which showed k values of −0.083 and −0.066 min−1 in the reduction of methylene blue and methyl orange, proving the accessibility of the Pd NPs.

Crystal structure of poly[hexa-μ-bromido-bis{2-[1-(pyridin-2-yl)ethylideneamino]ethanolato}tetracopper(II)

The reaction of the Schiff base 2-[1-(pyridin-2-yl)ethylideneamino]ethanol (HL), which is formed by reaction of 2-aminoethanol and 2-acetylpyridine with CuBr2 in ethanol results in the isolation of the new polymeric complex poly[hexa-μ-bromido-bis{2-[1-(pyridin-2-yl)ethylideneamino]ethanolato}tetracopper(II)], [Cu4Br6(C9H11N2O)2] n or [Cu4Br6 L 2] n . The asymmetric unit of the crystal structure of the polymeric [Cu4Br6 L 2] n complex is composed by four copper (II) cations, two monodeprotonated molecules of the ligand, and six bromide anions, which act as bridges. The ligand molecules act in a tridentate fashion through their azomethine nitrogen atoms, their pyridine nitrogen atoms, and their alcoholate O atoms. The crystal structure shows two types of geometries in the coordination polyhedrons around Cu2+ ions. Two copper cations are situated in a square-based pyramidal environment, while the two other copper cations adopt a tetrahedral geometry. Bromides anions acting as bridges between two metal ions connect the units, resulting in a tetranuclear polymer compound.

Synergistic effect of oxygen-containing and nitrogen-containing groups on promoting low-temperature denitration over non-metallic carbon-based catalyst

Oxygen-containing and nitrogen-containing groups on the surface of non-metallic carbon-based catalysts have been regarded as active sites for NH3 selective catalytic reduction (NH3-SCR) of nitrogen oxides (NOx) at low temperature. In this study, series of AC-xO-yN catalysts were prepared via grafting oxygen-containing and/or nitrogen-containing groups on active carbon (AC). The activity test results showed that the denitration efficiency of AC-5O-0 N and AC-0O-4 N catalyst were only 20 and 44 % at a temperature of 120 °C and a GHSV of 4500 h−1, respectively, while the activity of the AC-5O-4 N catalysts reached 97 % at the same condition, indicating that the oxygen-containing and nitrogen-containing groups exhibited a superior synergistic effect in facilitating the low-temperature NH3-SCR denitration reaction. Characterization results revealed that the oxygen-containing groups (mainly carboxyl and lactone groups) contribute to NH3 adsorption and activation, while the nitrogen-containing groups (especially pyridine nitrogen groups) could promote NO adsorption and oxidation. The co-existence of oxygen-containing and nitrogen-containing groups can synergistically advance the low-temperature NH3-SCR denitration reaction on the surface of the AC catalyst via a fast SCR route. This work might provide insight into designing and preparing non-metallic carbon-based catalysts with high denitration performance.

Self-nitrogen-doped carbon spheres assisted CeO2 composites as a bifunctional adsorbent/photocatalyst for CO2 photoreduction

It is rather essential to increase CO2 adsorption and improve separation efficiency of photoinduced carriers by solar-driven CO2 reduction. Herein, we proposed a facile approach to synthesize millimeter-sized polyacrylonitrile-based carbon spheres (PANACSs) as a bifunctional adsorbent and self-nitrogen-doped source under a mild condition, and then embeds the highly active CeO2 to construct a CeO2@PANACSs composite with strong adsorption capacity and high reduction activity. The involved XRD, XPS, SEM, N2 adsorption/desorption, CO2 adsorption, UV–vis DRS, EIS, PL and In situ FTIR spectra were characterized. Results suggested that the obtained PANACSs can act as a catalyst to drive the reduction of CO2 into CO under visible light irradiation. CeO2@PANACSs showed the highest performance of photocatalytic reduction of CO2 for 10 h (210.65 μmol·g−1), and the yield of CO evolution is approximately 1.83 times and 17.42 times higher than that of pristine CeO2 and PANACSs, respectively. We found that the existence of nitrogen-containing functional groups further promoted the adsorption and activation of CO2. Among them, pyridinic nitrogen and pyrrolic nitrogen can be used as adsorption and activation sites to accelerate the separation and transfer of e--h+. Furthermore, Ce4+ on the surface of CeO2 acts as an electron capture agent, which captures the electrons that are not transferred in time and reduces itself to Ce3+, and then the formed Ce3+ reduces the adsorbed CO2 to CO. Finally, the possible mechanism is proposed to depict the photocatalytic CO2 reduction over the CeO2@PANACSs. Our finding provides a noteworthy promising strategy to construct bifunctional composite photocatalysts for achieving the high-efficient CO2 adsorption and photoreduction to CO.

Simultaneous regeneration of activated carbon and removal of adsorbed atrazine by ozonation process: From laboratory scale to pilot studies

A novel treatment technique by coupling granular activated carbon (GAC) adsorption and ozone regeneration was constructed for long-lasting water decontamination. The GAC adsorption showed high performance for atrazine (ATZ) removal (99.9 %), and the ozone regeneration ensured the recyclability of GAC for water purification. The regeneration process was evaluated via several paths to assist the efficient adsorption process. Employing ozone micro-nano bubbles (O3-MNBs) for regenerating GAC showed superior performance compared to traditional ozone. Meantime, inhibiting the formation of bromate (BrO3−). ATZ adsorption process suffered from the pore-filling, hydrogen bonding effect and π-π EDA interaction. The surface phenolic hydroxyl group, carboxyl group and pyridine nitrogen benefitted the triggering of ozone to generate reactive oxygen species, and regenerate the GAC surface. The superior performance of the adsorption and regeneration process was verified via a long-term running by a pilot study. It significantly improved the removal of organic micropollutants, UV254 and permanganate index. Additionally, the intermittent O3-MNBs regeneration process resulted in efficient decontamination within the pores structure of GAC, which also effectively preserved the pore structure from destruction. For actual application, the cost of water production can be saved around 0.63 kWh m−3. This work proposed new ideas and theoretical support for economic water production.

Coordinately unsaturated single Fe-atoms with N vacancies and enhanced sp3 carbon defects in Fe-N(sp2)-C structural units for suppression of cancer cell metabolism and electrochemical oxygen evolution.

Installing coordinately unsaturated Fe-N-C structural units on polymer-composite-derived N-doped carbon offers highly active Fe-Nx sites for the electrochemical oxygen evolution reaction (OER) and reactive oxygen species (ROS) generation in tumor cells. An NH4Cl-driven high-temperature etching method was employed for the formation of FeSA950NC with coordinately unsaturated single Fe-atoms in an Fe-N(sp2)-C structural unit together with N vacancies (VN) and sp3 defects. The carbonization of Fe-phen@ZIF-8 at 800 °C for 30 min under argon, followed by grinding Fe-ZIF-8@RF-urea with NH4Cl at 950 °C for 2 hours, resulted in sp3 carbon defects and VN sites with coordination unsaturation in Fe-Nx due to NH4Cl decomposition to NH3 and HCl, which produced substantial internal stress for etching the carbon matrix. FeSA950NC was used to treat both A549 lung cancer cells and NIH3T3 mouse fibroblast cells to determine its potential as an efficient tumor therapeutic strategy using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and ROS assays. Additionally, FeSA950NC provided high stability and excellent OER activity through the Fe-N(sp2)-C structural unit on pyridinic nitrogen by delivering at a minimum overpotential of 300 mV, which is much lower than that of structurally similar Fe-atom sites. The significantly stronger ROS and OER activities of FeSA950NC suggested the role of VN and sp3-carbon defects with coordinately unsaturated Fe-N2 sites in improving its catalytic performance.

Synthesis, antimicrobial activity and application of polymers of praseodymium complexes based on pyridine nitrogen oxide.

The traditional pyridine nitrogen oxide-based antimicrobial agents are often associated with health risks due to heavy metal enrichment. To mitigate this concern, we synthesized two novel complexes, Pr2(mpo)6(H2O)2 and Pr(hpo)(mpo)2(H2O)2, and integrated rare-earth salts, Hhpo (2-hydroxypyridine-N-oxide) and Nampo (2-mercapto-pyridine-N-oxide sodium salt). These complexes were characterized through infrared analysis, elemental analysis, thermogravimetric analysis, and X-ray crystallographic analysis. Our comparative analyses demonstrate that the synthesized rare-earth complexes exhibit stronger antimicrobial activity against Staphylococcus aureus (S. aureus ATCC6538) and Escherichia coli (E. coli ATCC25922) compared to the ligands and rare-earth salts alone. Quantitative results revealed the lowest inhibitory concentrations of the two complexes against S. aureus ATCC6538 and E. coli ATCC25922 at 3.125 μg mL-1, 6.25 μg mL-1, 3.125 μg mL-1 and 6.25 μg mL-1, respectively. Preliminary investigations indicated that the antibacterial mechanism of these complexes involved promoting intracellular substance exudation to achieve antibacterial effects. Incorporation of these complexes into polymeric antimicrobial films resulted in a potent antimicrobial effect, achieving a 100% inhibition rate against S. aureus ATCC6538 and E. coli ATCC25922 at a low addition level of 0.6 wt%. Our results suggest that nitrogen oxide-based praseodymium complexes have potential for various antimicrobial applications.

Polarisation effects on the H-bond acceptor properties of sulfonamides.

The strengths of H-bonding interactions in networks are affected by cooperativity between the interacting sites. Compounds with an intramolecular H-bond between a sulfonamide NH group and pyridine nitrogen were used to measure the magnitude of cooperative effects on intermolecular H-bonding interactions with the sulfonamide oxygen. X-ray crystallography and 1H NMR experiments confirm the presence of the intramolecular H-bond and show that it is maintained in the 1 : 1 complex formed with perfluoro-tert-butanol (PFTB) in n-octane solution. Association constants for formation of 1 : 1 complexes with PFTB were determined using UV/Vis absorption titrations for a series of compounds equipped with different pyridine groups. Substituents on the pyridine were used to tune the strength of the intramolecular H-bond and investigate the effects on the strength of the intermolecular H-bond. Electron-donating groups on the pyridine that increase the strength of the intramolecular H-bond were found to increase in the strength of the intermolecular interaction with PFTB. The results were used to determine the H-bond acceptor parameters, β, for the sulfonamide oxygen group, and the values show a linear relationship with the value of β for the pyridine nitrogen. The slope of this relationship corresponds to the cooperativity parameter, κ, which is +0.16. The positive cooperativity observed in H-bonded sulfonamides is comparable to the value measured previously for the amide group (κ = +0.20).

Negative cooperativity in the formation of H-bond networks involving primary anilines.

Networks of H-bonds can show non-additive behaviour, where the strength of one interaction perturbs another. The magnitude of such cooperative effects can be quantified by measuring the effect of the presence of an intramolecular H-bond at one site on a molecule on the association constant for formation of an intermolecular H-bond at another site. This approach has been used to quantify the cooperativity associated with the interaction of a primary amine with two H-bond acceptors. A series of compounds that have an intramolecular H-bond between an aniline NH2 group and a pyridine nitrogen were prepared, using polarising substituents on the pyridine ring to vary the strength of the intramolecular H-bond. The presence of the intramolecular interaction was confirmed by X-ray crystallography in the solid state and NMR spectroscopy in n-octane solution. UV-vis absorption titrations were used to measure the association constants for formation of an intermolecular H-bond with tri-n-butyl phosphine oxide in n-octane. Electron-donating substituents on the pyridine ring, which increase the strength of the intramolecular H-bond, were found to decrease the strength of the intermolecular H-bond between the aniline and the phosphine oxide. The results were used to determine the H-bond donor parameters for the anilines, α, and there is a linear relationship between the values of α and the H-bond acceptor parameter of the pyridine group involved in the intramolecular H-bond, β. The slope of this relationship was used to determine the cooperativity parameter (κ = -0.10), which quantifies the negative allosteric cooperativity between the two H-bonding interactions. Calculated molecular electrostatic potential surfaces of the anilines quantitatively reproduce the experimental result, which suggests that effects are electrostatic in origin, either due to polarisation of the NH bonds or due to secondary electrostatic interactions between the two H-bond acceptors.

Microporous Nitrogen-Doped Activated Biochars Derived from Corn: Use of Husk Waste and Urea for CO2 Capture

The increase in anthropogenic activity over time has led to an exponential increase in greenhouse gas emissions, especially CO2. Profitable technologies for CO2 capture and separation are conspicuous, and porous biochars derived from biomass waste can be a useful solution. Herein, we produced activated nitrogen-doped biochars for CO2 capture from corn husk waste, urea and K2CO3, named N-Bio-X (X = 600, 700, and 800 °C). N-Bio-X exhibited microporosity and different nitrogen contents and thus played an important role in the adsorption of CO2. N-Bio-700 exhibited the highest CO2 adsorption capacity, fastest adsorption kinetics and excellent stability after multiple adsorption-desorption cycles. N-Bio-600 showed excellent CO2/N2 selectivity, induced by nitrogen sites, particularly pyridinic and graphitic nitrogen. The cost-effectiveness of the raw material, coupled with its high adsorption capacity, rapid kinetics, and stable properties, provided highly promising N-doped biochars for practical implementation in CO2 capture and separations in postcombustion processes.

Polymerization of Brominated Aromatic Compounds within a Metal-Organic Framework toward Bottom-up Synthesis of Graphene Nanoribbons with Either Pyridinic or Tertiary Nitrogen

Polymerization of Brominated Aromatic Compounds within a Metal-Organic Framework toward Bottom-up Synthesis of Graphene Nanoribbons with Either Pyridinic or Tertiary Nitrogen

P-Phenylenediamine-derived carbon nanodots for probing solvent interactions.

Carbon nanodots, the luminescent nanoparticles of carbon with size restriction below 10 nm, have attracted inordinate attention in materials science due to their widespread applications in optoelectronic and biological fields. Low toxicity and facile synthesis pathways render them favourites in the above-mentioned areas in the context of green chemistry. This work presents fine applications of p-phenylenediamine-derived carbon nanodots (PD-CNDs) achieved via a facile one-pot hydrothermal method. Adequate characterization using X-ray diffraction and spectroscopic and microscopic studies confirmed spherical particles with an average particle size of 2.8 nm, functionalised with amino, carboxyl, and hydroxyl groups. The carbon framework was functionalised with pyridinic and pyrrolic nitrogens. Upon 365 nm UV light illumination, an aqueous dispersion of PD-CNDs showed red-orange fluorescence. Detailed spectral analysis using UV-visible absorption and fluorescence spectroscopy identified edge states and surface groups as luminescent centres, with a significant contribution arising from the latter. The investigation conducted using a collection of solvents, categorized into polar and nonpolar, indicated the potential of the system for applications based on its solvatochromic nature. The feature enabled the determination of different polarity parameters of the solvents, as well as dielectric constants of solvents and solvent mixtures, with considerable accuracy. The system was potent for predicting the composition of a given pair of solvents. The service of the system is also extended for moisture sensing in organic solvents within an error percentage < 1. High quantum yield values (0.61) combined with solvent composition-dependent optical features ensure broader applications of the system to probe solvent interactions.

Evaluation of Nitrogen-Doped Adsorbents Based on Reduced Graphene Oxide as Platforms for CO2 Capture

CO2 emissions into the atmosphere have been rapidly rising due to human activities, resulting in the escalation of global warming. To mitigate climate change, it is imperative to develop materials for CO2 capture with high CO2 capacity and low production costs. Herein, we developed a facile method to obtain adsorbents based on reduced graphene oxide (rGO) sheets, NrGO(1 - X)700, where X represents the mass of diethylenetriamine (DETA) (X = 1, 2 and 4 g) used in the preparation. The materials NrGO(1 - 1)700, NrGO (1 - 2)700, and NrGO(1 - 4)700 were obtained from graphene oxide dispersions, followed by DETA impregnation and chemical activation with K2CO3. N2 isotherms demonstrated that the materials simultaneously presented micro and mesopores with similar values of specific surface area (280.16 to 310.32 m2 g-1), pore volume (0.26 to 0.28 cm3 g-1) and pore size (3.78 to 3.80 nm). CO2 sorption experiments revealed that the material NrGO(1 - 4)700, containing the highest amount of pyridinic, graphitic, and amino nitrogen functionalities, showed the best CO2 adsorption capacity. Diffuse reflectance Fourier transformed infrared spectroscopy experiments indicated stronger solid-gas interactions for NrGO(1 - 4)700 than for the other materials.

Photodynamics of azaindoles in polar media: the influence of the environment.

We have studied the relaxation dynamics of a family of azaindole (AI) structural isomers, 4-, 5-, 6- and 7-AI, by steady-state and time-resolved methods (fs-transient absorption and fluorescence up-conversion), in solvents of different polarity. The measurements in aprotic solvents show distinctive fluorescence yields and excited state lifetimes among the isomers, which are tuned by the polarity of the medium. Guided by simple TD-DFT calculations and based on the behavior observed in the isolated species, it has been possible to address the influence of the environment polarity on the relaxation route. According to the obtained picture, the energy of the nπ* state, which is strongly dependent on the position of the pyridinic nitrogen, controls the rate of the internal conversion channel that accounts for the distinctive photophysical behavior of the isomers. On the other hand, preliminary measurements in protic media (methanol) show a very different photodynamical behavior, in which the anomalous measured fluorescent patterns are very likely the result of reactive channels (proton transfer) triggered by the electronic excitation.

Boron–pyridine nitrogen cooperative catalytic conversion of carbon dioxide and epoxides to cyclic carbonates

A type of N-heterocyclic carbene (NHC)-diboron adduct in combination with tetrabutylammonium iodide (TBAI) was used as a catalyst for the synthesis of cyclic carbonates from CO2 with epoxides.

Combined effect of amino nitrogen and pyridine nitrogen for tetracycline adsorption on aminopyridine modified MIL-101(Cr)

xApy-MIL-101(Cr) was successfully synthesized by incorporating 4-aminopyridine, and it was employed for adsorption of tetracycline in wastewater.