Heteroatom Functionalities Research Articles

Frustrated Lewis Pair-Mediated Cycloisomerization of Propargylaniline and Aryl Propargyl Ether Derivatives via a 6-endo-dig Cyclization/Dehydrogenation Sequence.

An efficient FLP-mediated cycloisomerization is described, providing easy access to quinolinium and chromenylium derivatives by treatment of readily available propargylanilines and aryl propargyl ethers with Lewis acidic boranes, respectively. The reaction proceeds via a 6-endo-dig cyclization/dehydrogenation sequence. The heteroatom functions serve as Lewis bases in combination with Lewis acidic boranes to effect synergistic activation of an alkynyl triple bond and a C-H bond.

Tailoring Pore Architecture and Heteroatom Functionality of Polymeric Waste-Derived Nanoporous Carbon for CO2 Capture Applications

Tailoring Pore Architecture and Heteroatom Functionality of Polymeric Waste-Derived Nanoporous Carbon for CO₂ Capture Applications

Rice husk-derived nitrogen-doped graphitic carbon/graphene nanosheets self-assembly for high-performance supercapacitors with chemical blowing method

Carbon materials derived from waste biomass are increasingly popular in energy devices due to their renewability, environmental benefits, and rich heteroatom functionalization. Herein, a simple and low-cost method for synthesising rice husk-derived nitrogen-doped graphitic carbon/graphene nanosheets (RNGNs) by chemical blowing was developed. Carbon was derived from rice husk (RH), while nitrogen was sourced from ethylenediaminetetraacetic acid and iron sodium salt hydrate (EDTA-FE), serving multiple roles as a blowing agent, an activating agent and a graphitization catalyst in a closed system. This approach facilitates the formation of a unique 3D structure of 2D graphene self-assembly on the wrinkled surface of graphitic carbon. As an electrode material for supercapacitors, the obtained RNGN800–1:1 with high nitrogen content (5.02 %) shows good electrical conductivity and a large specific surface area (1130 m2 g−1). These characteristics bring about an impressive electrochemical performance (334.5 F g−1 at 0.5 A g−1, 75.6 % retention at 20 A g−1). Moreover, when assembled into symmetrical device, the RNGN800–1:1 demonstrates a high power density of 9.4 kW kg−1and an excellent energy density of 15.2 Wh kg−1 with outstanding long-term cyclability (remains 94.77 % after 25000 cycles). This study introduces a straightforward and environmentally friendly approach for synthesizing nitrogen-doped graphitic carbon/graphene nanosheets from sustainable biomass resources. The resulting material is expected to have broad applications across various areas, including adsorption, catalysis, and energy storage.

Harmonizing Between Chemical Functionality and Surface Area of Porous Organic Polymeric Nanotraps for Tuning Carbon Dioxide Capture.

The energy sector has demonstrated significant enthusiasm for investigating post-combustion CO2 capture, storage, and separation. However, the practical application of current porous adsorbents is impeded by challenges related to cost competitiveness, stability, and scalability. Intregation of heteroatoms in the porous organic polymers (POPs) dispense it more susceptible for CO2 adsorption to attenuate green house gases. In this regard, two hydroxy rich hypercrosslinked POPs, namely Ph/Tt-POP have been developed by one-pot condensation polymerization using a facile synthetic strategy. The high surface areas of both the Ph/Tt-POP (1057 and 893 m2g-1, respectively), and the heteroatom functionality in the POP framework instigated us to explore our material for CO2 adsorption study. The CO2 uptake capacities in Ph/Tt-POP are found to be 2.45 and 2.2 mmol g-1, at 273 K respectively. Further, in-situ static 13C NMR experiment shows that CO2 molecules in Tt-POP appear to be less mobile than those in Ph-POP which probably due to the presence of triazine functional groups along with high abundant -OH groups in the Tt-POP framework. An in-depth study of the CO2 adsorption mechanism by density functional theory (DFT) calculations also shows that CO2 adsorption at the cages formed by two benzyl rings represents the most stable interaction and CO2 molecule is more favorably adsorbed on the Ph-POP with the more negative interaction energies values compared to that of Tt-POP. Further, Non-covalent interaction (NCI) plot reveals that CO2 molecules adsorb more on the Ph-POP than Tt-POP, which can be explain by hydrogen bond formation in case of Tt-POP repeating units turning aside CO2 molecule to interact with the Ph component. Overall, our present study reflects the comprising effects of surface area of the solid adsorbents as well as their functionality can be beneficial for developing efficient hypercrosslinked porous polymers as solid CO2 adsorbent.

Selective Profiling of Carboxylic Acid in Crude Oil by Halogen Labeling Combined with Liquid Chromatography and High-Resolution Mass Spectrometry.

Carboxylic acids are a small but essential compound class within petroleum chemistry, influencing crude oil behaviors in production and processing and causing environmental impacts. Detailed structural information is fundamental to understanding their influence on petroleum characteristics. However, characterizing acids in crude oil remains challenging due to matrix effects, structural diversity, and low abundance. In this work, we present a new methodology for profiling carboxylic acids by liquid-liquid extraction and selective derivatization using 4-bromo-N-methylbenzylamine (4-BNMA) followed by liquid chromatography and electrospray ionization Orbitrap mass spectrometry (LC-ESI-Orbitrap MS). The fragmentation of 4-BNMA derivatives produces a unique product ion pair, m/z 169/171, enabling the identification of chromatographic fractions containing carboxylic acids. The mass spectra of the corresponding fractions are extracted, and the acids are further computationally isolated based on the isotopic pattern. The method was optimized and validated using acid standards and systematic experimental designs, assuring robustness and sensitivity for nontarget screening purposes. This method detected up to 380 carboxylic acids in six Danish North Sea crude oils, with up to two carboxyl and other heteroatom functionalities (NSO). The results indicated that the most populated species are fatty acids (double bond equivalent (DBE) = 1) and small aromatic acids (DBE = 2-6). The predominance and diversities of compound classes in different samples are consistent with their corresponding bulk properties. Polyfunctional acids (Ox, NxOx, and SxOx) were observed due to exposure to oxidation and biodegradation. Also, the approach's applicability benefits high-resolution MS analysis by simplifying data processing for crude oil and potentially other high-organic and aqueous samples.

Highly Porous Cellulose-Based Carbon Fibers as Effective Adsorbents for Chlorpyrifos Removal: Insights and Applications

The extensive utilization of the organophosphate pesticide chlorpyrifos, combined with its acute neurotoxicity, necessitates the development of effective strategies for its environmental removal. While numerous methods have been explored for chlorpyrifos removal from water, adsorption is the most promising. We investigated the potential of two cellulose-derived porous carbons as adsorbents for chlorpyrifos removal from water, prepared by either CO2 or H2O activation, resulting in similar morphologies and porosities but different amounts of heteroatom functionalities. The kinetics of batch adsorption removal from water fits well with the pseudo-first-order and pseudo-second-order kinetic models for both materials. The Freundlich, Langmuir, Dubinin–Radushkevich, and Sips isotherm models described the process of chlorpyrifos adsorption very well in all investigated cases. The maximum adsorption capacity determined from the Sips isotherm model gave values of 80.8 ± 0.1 mg g−1 and 132 ± 3 mg g−1 for the H2O and CO2 activated samples, respectively, reflecting the samples’ differences in heteroatom functionalities. Additionally, the application of either adsorbent led to reduced toxicity levels in all tested samples, implying that no harmful by-products were generated during adsorption. Comparative analysis with the existing literature further validates the study’s findings, suggesting the efficacy and applicability of cellulose-based porous carbons for sustainable chlorpyrifos remediation.

Recent advances and research progress on the role of carbon‐based biomass in ultra‐capacitors: A systematic review

AbstractBiomass‐derived carbon material has drawn significant attention recently due to its wide availability, environmentally free, and effective performance of the resulting porous carbons for supercapacitor (SC) applications. Carbon electrode material derived from biomass is used for energy storage (ES) because it has distinct qualities in porosity, a large specific surface area, and excellent conductivity. Furthermore, these materials' homogeneous, flawless biological structures can be used as models to create electrode materials with accurate geometries. The ES devices, known as SCs, also known as ultra‐capacitors, serve as a link between a capacitor and a battery. Due to their charge storage, SCs can produce a much higher density than batteries. Several factors, including the electrode's potential window, the electrode materials characteristics, and the electrolyte choice, have a major effect on SC performance. Therefore, all efforts have been made to develop SC electrode materials. This paper explains the different types of SCs and how they work. The various available biomass resources, as well as the methods for producing them, are outlined. In addition, the different types of electrode materials, activation methods, heteroatom functionalization, and electrolyte types are all thoroughly examined. The application and research advancement of biomass‐derived carbon used in SCs over the past 3 years are highlighted. Furthermore, this research outlines the benefits of SCs for the environment and the economy, as well as present challenges and future recommendations for advancing biomass‐derived carbon applications. This article aims to give an in‐depth knowledge of carbon‐based biomass materials that are used in SCs.

Facile phosphorus and oxygen heteroatom functionalization of biochar based on biomass prepared by microwave pyrolysis for adsorption process of cadmium in aqueous solution

AbstractIn this study, in the first stage, biochar is produced from green pistachio hulls (PGHMAC) by microwave heating method, which saves energy, time and cost. In the second step, with the activation of phosphoric acid (H3PO4), the surface properties of the biochar were modified by phosphorus (P) and oxygen (O) doping (O- and P-doped PGHMAC). This adsorbent obtained was applied to remove cadmium (Cd(II)) from wastewater. FTIR, SEM, EDX, and ICP-OES analyses were used for the characterization of the samples. FTIR, EDX, and ICP-OES analysis results showed the presence of oxygen and phosphorus groups on the surface of the relevant adsorbent. The contents of C and O atoms for P- and O-doped PGHMAC were found to be 62.54% and 36.12%, respectively. Also, about 1.29% of P atoms were found with H3PO4 activation. The kinetic, isotherm, and thermodynamic parameters of the adsorption studies were investigated. Maximum Cd(II) adsorption capacities of P- and O-doped PGHMAC at 298 K, 308 K, and 318 K temperatures were calculated as 78.74, 109.89, and 133.33 mg/g by Langmuir model, respectively. The mechanism of Cd(II) adsorption on O- and P-doped PGHMAC has been proposed.

Optimizing Porosity and Heteroatom Functionalities in Amorphous Carbon-Rich g-C3N4 for Dual-Mode Photocatalysis through Solar to Green Hydrogen and Chemical Energy Conversion

Optimizing Porosity and Heteroatom Functionalities in Amorphous Carbon-Rich g-C₃N₄ for Dual-Mode Photocatalysis through Solar to Green Hydrogen and Chemical Energy Conversion

Oxidative Dearomatization of Pyridines.

Dearomatization of pyridines is a well-established synthetic approach to access piperidines. Although remarkably powerful, existing dearomatization processes have been limited to the hydrogenation or addition of carbon-based nucleophiles to activated pyridiniums. Here, we show that arenophile-mediated dearomatizations can be applied to pyridines to directly introduce heteroatom functionalities without prior substrate activation. The arenophile platform in combination with olefin oxidation chemistry provides access to dihydropyridine cis-diols and epoxides. These previously elusive compounds are now readily accessible and can be used for the downstream preparation of diversely functionalized piperidines.

Fluorinated Graphene Fillers for High-Performance Solid-State Lithium Batteries

Solid-state batteries (SSBs) are expected to revolutionize the field of energy storage due to their superior safety and high energy density, which result from the use of lithium metal as the negative electrode. However, the development of solid-state electrolytes (SSEs), the key component of SSBs, is quite crucial. SSEs have high thermal stability, high mechanical strength, and a wide electrochemical window but lack enough ionic conductivity; which is one of the most challenging aspects. Incorporating suitable active or inert fillers in the solid polymer electrolyte matrix is one of several methods adopted to improve the ionic conductivity of pure polymer SSEs. Two-dimensional graphene-based fillers are a promising option as they provide a high surface area for creating an abundant interface with the polymer matrix creating a continuous pathway for lithium-ion transport and simultaneously their robust nature improves the mechanical strength of the electrolyte. Pristine graphene is electronically conducting in nature owing to the continuous sp2 carbon linkages, but the electronic conductivity can be suppressed by disrupting the sp2 bonds by heteroatom functionalization on the graphene. This study investigates the heteroatom functionalization of graphene to obtain various graphene-based fillers such as graphene oxide (GO), reduced graphene oxide (rGO), and fluorinated graphene oxide (FGO) and their effectiveness when introduced into a polymer SSE matrix for LiNi0.8Co0.1Mn0.1O2-based SSBs. FGO filler outperforms others in terms of ionic conductivity, thermal stability, enhanced electrochemical potential window, and compatibility of the SSE. The optimized ratio of FGO fillers in SSE demonstrates excellent electrochemical performance, enabling long-term Li plating/stripping with small overpotential and stable cycling of Li/ LiNi0.8Co0.1Mn0.1O2 full cells. This work highlights the notable potential of FGO materials in improving the comprehensive properties of polymer SSEs and promoting the applications of polymer SSEs in high-performance SSBs.

Elucidation of Surface Functional Groups Deposited by Electrochemical Surface Treatment of Discontinuous Carbon Fiber by NEXAFS and XPS.

Control of carbon fiber heteroatom (oxygen and nitrogen) functionalization using electrochemical oxidation is explored in a variety of electrolyte solutions. Results of X-ray photoelectron spectroscopy (XPS) and near-edge X-ray absorption fine structure (NEXAFS) spectroscopy indicate that most electrolytes in aqueous and anodic conditions are limited to heteroatom surface content of no more than 13 atomic percent (at %) with a majority C-O and/or C-N moieties; the remaining moieties include an oxidative sequence of carbon (alcohol to ketone to carboxylate) and more complex O- and N-containing groups. The pH of the electrolyte solution was found to be crucial in controlling the ratio of the amount of oxygen to nitrogen functionalities, with the increased basicity of solution resulting in higher nitrogen deposition. The oxidative (and/or thermal) decomposition of many electrolytes during electrochemical treatment can have a major impact on functionalization through changes to pH. Oxidation of carbon fiber in some electrolyte solutions showed higher surface concentrations of heteroatoms (25-30 at %) than most electrolytes (13 at %). Mechanisms were proposed to explain how some electrolytes can exceed 13 at % of heteroatom deposition. Specifically, we hypothesized that electrolytes that contain organic ions with chelation capabilities and moieties that produce additional sites of functionalization can overcome that threshold.

Prominent Structural Dependence of Quantum Capacitance Unraveled by Nitrogen-Doped Graphene Mesosponge.

Porous carbons are important electrode materials for supercapacitors. One of the challenges associated with supercapacitors is improving their energy density without relying on pseudocapacitance, which is based on fast redox reactions that often shorten device lifetimes. A possible solution involves achieving high total capacitance (Ctot), which comprises Helmholtz capacitance (CH) and possibly quantum capacitance (CQ), in high-surface carbon materials comprising minimally stacked graphene walls. In this work, a templating method is used to synthesize 3D mesoporous graphenes with largely identical pore structures (≈2100 m2 g-1 with an average pore size of ≈7nm) but different concentrations of oxygen-containing functional groups (0.3-6.7 wt.%) and nitrogen dopants (0.1-4.5 wt.%). Thus, the impact of the heteroatom functionalities on Ctot is systematically investigated in an organic electrolyte excluding the effect of pore structures. It is found that heteroatom functionalities determine Ctot, resulting in the cyclic voltammetry curves being rectangular or butterfly-shaped. The nitrogen functionalities are found to significantly enhance Ctot owing to increased CQ.

Modular and Practical 1,2‐Aryl(Alkenyl) Heteroatom Functionalization of Alkenes through Iron/Photoredox Dual Catalysis**

AbstractEfficient methods for synthesizing 1,2‐aryl(alkenyl) heteroatomic cores, encompassing heteroatoms such as nitrogen, oxygen, sulfur, and halogens, are of significant importance in medicinal chemistry and pharmaceutical research. In this study, we present a mild, versatile and practical photoredox/iron dual catalytic system that enables access to highly privileged 1,2‐aryl(alkenyl) heteroatomic pharmacophores with exceptional efficiency and site selectivity. Our approach exhibits an extensive scope, allowing for the direct utilization of a wide range of commodity or commercially available (hetero)arenes as well as activated and unactivated alkenes with diverse functional groups, drug scaffolds, and natural product motifs as substrates. By merging iron catalysis with the photoredox cycle, a vast array of alkene 1,2‐aryl(alkenyl) functionalization products that incorporate a neighboring azido, amino, halo, thiocyano and nitrooxy group were secured. The scalability and ability to rapid synthesize numerous bioactive small molecules from readily available starting materials highlight the utility of this protocol.

Modular and Practical 1,2-Aryl(Alkenyl) Heteroatom Functionalization of Alkenes through Iron/Photoredox Dual Catalysis.

Efficient methods for synthesizing 1,2-aryl(alkenyl) heteroatomic cores, encompassing heteroatoms such as nitrogen, oxygen, sulfur, and halogens, are of significant importance in medicinal chemistry and pharmaceutical research. In this study, we present a mild, versatile and practical photoredox/iron dual catalytic system that enables access to highly privileged 1,2-aryl(alkenyl) heteroatomic pharmacophores with exceptional efficiency and site selectivity. Our approach exhibits an extensive scope, allowing for the direct utilization of a wide range of commodity or commercially available (hetero)arenes as well as activated and unactivated alkenes with diverse functional groups, drug scaffolds, and natural product motifs as substrates. By merging iron catalysis with the photoredox cycle, a vast array of alkene 1,2-aryl(alkenyl) functionalization products that incorporate a neighboring azido, amino, halo, thiocyano and nitrooxy group were secured. The scalability and ability to rapid synthesize numerous bioactive small molecules from readily available starting materials highlight the utility of this protocol.

(Invited) Modification of Properties of N- and B-Doped Graphene by Heteroatom Functionalization

Since its discovery in 2004, the graphene has attracted great attention owing to its unique chemical bonding structure, which has excellent chemical, thermal, mechanical, electrical and optical properties. Due to the graphene being a zero band-gap material, it has a limited development in the field of nano electronics. Therefore, to broaden its application scope, it is very important to carry out a study on opening the band gap of graphene. One general strategy for achieving this goal is doping graphene with heteroatoms; in this approach, the properties of graphene are controlled by the nature of the dopant elements and by the percentage of doping being N-doped graphene is of n-type doping, while B-doped graphene is of p-type doping. Compared with that of the intrinsic graphene, the Fermi level of N doped graphene moves up 5 eV; on the contrary, the Fermi level of B doped graphene moves down 3 eV.However, it would be convenient to develop additional tools to achieve further control of the electronic properties of graphene materials. In this context, one of the possibilities would be to functionalize those dopant elements on the graphene sheet in such a way that the electron density and electronegativity of the heteroatom are effectively controlled. This objective could, in principle, be achieved by applying concepts from organic chemistry. Organic synthesis offers proven chemical reactions that are applicable to different types of nitrogen and boron compounds.In the work described here, we´ll present our results on the covalent functionalization of the nitrogen atom or boron atom of N-doped and B-doped graphene. In a simple strategy, electron-donating and -withdrawing groups present on aromatic rings can be used to modulate the electronic properties of the material.

Corn-straw-converted activated carbons with tunable porosity and N/O functionalities as high-performance supercapacitors electrode at commercial-level mass loading

With the scientific importance and industrial need for low-cost but high-performance activated carbons (ACs) for supercapacitors (SCs), ACs with tailorable porous texture and heteroatom doping are turned from corn straw via hydrothermal and activation processes. Porous texture is mainly adjusted by KOH/biochar mass ratio. O and N surface functionalities are tuned by a subsequent high-temperature treatment by H2O or ammonia. The influences of porosity in the amounts of the introduced N contents are investigated. With symmetric SC cells, the electrochemical performances of the corn-straw-derived ACs are examined at commercial-level mass loading. For aqueous electrolyte, the ACs prepared without KOH activation but with high-temperature treatment by ammonia exhibit high gravimetric capacitance of 192 F/g and volumetric capacitance of 150 F/cm3 due to their high compact density and N atomic fraction. For organic system, the optimum ACs are activated with KOH/biochar ratio of 1:1 and a subsequent ammonia high-temperature treatment, which deliver high gravimetric capacitance of 258 F/g and volumetric capacitance of 167 F/cm3. Balanced porosity and density, low O fraction but high N fraction are found to be favored for organic system. The cost-effective technique route may provide guidance for the design and preparation of biomass-derived ACs with tunable porosity and heteroatom functionalities for practical applications in SCs.

Converting renewable saccharides to heteroatom doped porous carbons as supercapacitor electrodes

Supercapacitors have a high-power throughput and large cycle life, so designing a suitable electrode material is crucial. Saccharide-derived carbons have been explored as sustainable anodes for supercapacitor applications. Mono- and polysaccharides were analyzed with pre-treatment of precursors and activation to understand the critical roles of heteroatom(s) in the precursors and the functionalized architecture in the charge storage mechanism. Acid-base synergistic pre-treatment/activation resulted in an almost 10-fold enhancement in the surface area with multifaceted pore distribution, rendering enhanced charge storage. A dual effect of heteroatom functionalization and activation of saccharide precursors resulted in a high gravimetric capacitance of 172 F/g at 1 A/g in a symmetric two-electrode configuration of chitin polysaccharide samples with a power density of 5000 W/kg at 3.5 W h/kg. It showed capacity retention of up to 100% for over 10,000 cycles. The results widen the current understanding of the electrochemical behaviour of carbons using chemically treated modifications at precursor levels. It unravels the impacts of hierarchical pore size distribution achieved by pre-treatment resulting in higher energy/power density and cycling stability.

Heteroatom Functionalization of H-Terminated Diamond Surfaces.

Diamond surface functionalization has received significant research interest recently. Specifically, H-termination has been widely adopted because it endows the diamond surface with negative electron affinity and the hole carrier is injected in the presence of surface transfer dopants. Exploring different functional groups' attachment on diamond surfaces and their impact on the electronic structure, using wet and dry chemical approaches, would hence be of interest in engineering diamond as a semiconductor. Here, we report the functionalization of the H-terminated diamond surface with nitrogen and sulfur heteroatoms. Surface characterization of functionalized diamond surfaces shows that these groups are well-distributed and covalently bonded to diamonds. Four chemical functional groups (-SH, -S-S-, -S-O, and -S=O) were found on the sulfurized diamond surface, and two groups (-NH2 and =NH) upon amination. We also report co-functionalization of surface with N and S (N-S), where sulfurization promotes sequential amination efficiency with reduced exposure time. Electrical measurement shows that heteroatom-modified diamond surfaces possess higher conductivity than H-terminated diamonds. Density functional theory (DFT) shows that upon functionalization with various N/S ratios, the conduction band minimum and valence band maximum downshift, which lowers the bandgap in comparison to an H-terminated diamond. These observations suggest the possibility of heteroatom functionalizations with enhanced surface electrical conductivity on the diamond that are useful for various electronic applications.

Pyrolysis processes affecting polycyclic aromatic hydrocarbon profile of pineapple leaf biochar exemplified by atmosphere/temperature and heteroatom doping

The content of polycyclic aromatic hydrocarbons in pineapple leaf biochar was examined as a function of pyrolysis atmosphere (CO2 or N2), pyrolysis temperature (300–900 °C), and heteroatom (N, B, O, P, NP, or NS) doping. Without doping, the polycyclic aromatic hydrocarbon production was maximal (1332 ± 27 ng/g) in CO2 at 300 °C and minimal (157 ± 2 ng/g) in N2 at 700 °C. The main components naphthalene and acenaphthylene accounted for about 91% of the total polycyclic aromatic hydrocarbon in the biochar prepared under CO2 at 300 °C. Under the maximal polycyclic aromatic hydrocarbon production conditions (CO2, 300 °C), doping decreased the total hydrocarbon content by 49% (N), 61% (B), 73% (O), 92% (P), 93% (NB), and 96% (NS). The results shed new light on the management of polycyclic aromatic hydrocarbons in BC production by controlling the pyrolysis atmosphere and temperature in addition to heteroatom doping. Results significantly contributed to the development of circular bioeconomy.