Nitrogen-containing Molecules Research Articles

Proton Transfer Processes in 2-Butenenitrile Dimer Cation Studied by Mass-Selective Infrared Spectroscopy.

2-Butenenitrile (2-Bu) is a recently discovered crucial interstellar molecule. Herein, an abnormal NH band was observed in the infrared spectrum of the 2-Bu dimer cation, suggestive of a proton transfer reaction within the cluster. Through a comprehensive theoretical analysis of the IR spectrum of (2-Bu)2+, we discovered not only the formation of a new C-N bond through the attachment of one 2-Bu to another but also the occurrence of a proton transfer reaction in the cluster. This proton was identified as originating from the methyl group of the attaching 2-Bu in the cluster based on the analysis of IR spectra of (2-Bu)+ and [2-Bu-acrylonitrile (AN)]+. Furthermore, the detailed reaction process of this ion-molecule reaction is examined with theoretical calculation. This finding contributes significantly to our deeper understanding of ion-molecule reactions in the gas phase and the formation of nitrogen-containing prebiotic molecules in the interstellar medium.

Atomic Ruthenium-Promoted Cadmium Sulfide for Photocatalytic Production of Amino Acids from Biomass Derivatives.

Amino acids are the building blocks of proteins and are widely used as important ingredients for other nitrogen-containing molecules. Here, we report the sustainable production of amino acids from biomass-derived hydroxy acids with high activity under visible-light irradiation and mild conditions, using atomic ruthenium-promoted cadmium sulfide (Ru1/CdS). On a metal basis, the optimized Ru1/CdS exhibits a maximal alanine formation rate of 26.0 molAla ⋅ gRu -1 ⋅ h-1, which is 1.7 times and more than two orders of magnitude higher than that of its nanoparticle counterpart and the conventional thermocatalytic process, respectively. Integrated spectroscopic analysis and density functional theory calculations attribute the high performance of Ru1/CdS to the facilitated charge separation and O-H bond dissociation of the α-hydroxy group, here of lactic acid. The operando nuclear magnetic resonance further infers a unique "double activation" mechanism of both the CH-OH and CH3-CH-OH structures in lactic acid, which significantly accelerates its photocatalytic amination toward alanine.

Electrochemical Synthesis of C(sp3)-Rich Amines by Aminative Carbofunctionalization of Carbonyl Compounds.

Alkylamines form the backbone of countless nitrogen-containing small molecules possessing desirable biological properties. Despite advances in amine synthesis through transition metal catalysis and photoredox chemistry, multicomponent reactions that leverage inexpensive materials to transform abundant chemical feedstocks into three-dimensional α-substituted alkylamines bearing complex substitution patterns remain scarce. Here, we report the design of a catalyst-free electroreductive manifold that merges amines, carbonyl compounds and carbon-based radical acceptors under ambient conditions without rigorous exclusion of air and moisture. Key to this aminative carbofunctionalization process is the chemoselective generation of nucleophilic α-amino radical intermediates that readily couple with electrophilic partners, providing straightforward access to architecturally intricate alkylamines and drug-like scaffolds which are inaccessible by conventional means.

Carbon-Supported Ru-Ni and Ru-W Catalysts for the Transformation of Hydroxyacetone and Saccharides into Glycol-Derived Primary Amines.

Nitrogen-containing molecules are used for the synthesis of polymers, surfactants, agrochemicals, and dyes. In the context of green chemistry, it is important to form such compounds from bioresource. Short-chain primary amines are of interest for the polymer industry, like 2-aminopropanol, 1-aminopropan-2-ol, and 1,2-diaminopropane. These amines can be formed through the amination of oxygenated substrates, preferably in aqueous phase. This is possible with heterogeneous catalysts, however, effective systems that allow reactions under mild conditions are lacking. We report an efficient catalyst Ru-Ni/AC for the reductive amination of hydroxyacetone into 2-aminopropanol. The catalyst has been reused during 3 cycles demonstrating a good stability. As a prospective study, extension to the reactivity of (poly)carbohydrates has been realized. Despite a lesser efficiency, 2-aminopropanol (9 % yield of amines) has been formed from fructose, the first example from a carbohydrate. This was possible using a 7.5 %Ru-36 %WxC/AC catalyst, composition allowing a one-pot retro-aldol cleavage into hydroxyacetone and reductive amination. The transformation of cellulose through sequential reactions with a combination of 30 %W2C/AC and 7.5 %Ru-36 %WxC/AC system gave 2 % of 2-aminopropanol, corresponding to the first example of the formation of this amine from cellulose with heterogeneous catalysts.

Heterocyclic-Based Analogues against Sarcine-Ricin Loop RNA from Escherichia coli: In Silico Molecular Docking Study and Machine Learning Classifiers

Background: Heterocyclic-based drugs have strong bioactivities, are active pharmacophores, and are used to design several antibacterial drugs. Due to the diverse biodynamic properties of well-known heterocyclic cores, such as quinoline, indole, and its derivatives, they have a special place in the chemistry of nitrogen-containing heterocyclic molecules. Objective: The objective of this study is to analyze the interaction of several heterocyclic molecules using molecular docking and machine learning approaches to find out the possible antibacterial drugs. Methods: The molecular docking analysis of heterocyclic-based analogues against the sarcin-Ricin Loop RNA from E. coli with a C2667-2'-OCF3 modification (PDB ID: 6ZYB) is discussed. Results: Many heterocyclic-based derivatives show several residual interaction, affinity, and hydrogen bonding with sarcin-Ricin Loop RNA from E. coli with a C2667-2'-OCF3 alteration which are identified by the investigation of in silico molecular docking analysis of such heterocyclic derivatives. Conclusion: The dataset from the molecular docking study was used for additional optimum analysis, and the molecular descriptors were classified using a variety of machine learning classifiers, including the GB Classifier, CB Classifier, RF Classifier, SV Classifier, KNN Classifier, and Voting Classifier. The research presented here showed that heterocyclic derivatives may operate as potent antibacterial agents when combined with other compounds to produce highly efficient antibacterial agents.

Research Progress and Prospect of Nitrogen-containing Heterocycle in Anti-gastric Cancer Drugs: A Review.

Gastric cancer was the fifth most common cancer, and its drug treatment mainly included chemotherapy, targeted therapy, and immunotherapy. With the rise of immunotherapy in gastric cancer, small-molecule anti-gastric cancer drugs still have irreplaceable places because of many advantages, such as high stability and mass-productivity, high efficiency, and low cost. At present, the small-molecule anti-gastric cancer drugs in the clinic are constrained by their side effects. So, developing more novel anti-gastric cancer drugs with better efficacy and fewer side effects is urgently needed. Nitrogen-containing heterocycle molecules have attracted much attention from researchers due to their high biocompatibility, activity, and bioavailability, and they even could act with a unique mechanism. This review summarized various types of nitrogen-containing heterocycle antigastric cancer lead compounds from 2017 to 2022 in the last five years. Compared with monocyclic nitrogen-containing heterocycle and bicyclic nitrogen-containing heterocycle, the thick nitrogen-containing heterocycle applied as the skeleton not only showed high efficiency and low toxicity but also, interestingly, may have had some unique mechanism such as inhibition of aurora A and B kinases, etc. We propose two prospective and valuable strategies to develop more efficient candidates for anti-gastric cancer. One strategy was further optimized for some lead compounds mentioned in this review. The other strategy involved utilizing the "pseudo-natural products" concept proposed by Professor Wilhelm Waldmann, combining different nitrogen-containing heterocycle fragments in two and three-dimensional spaces to obtain new thick nitrogen-containing heterocycle skeletons. The strategy will contribute to the expansion of the thick nitrogenous heterocycle's framework, and it was expected that more novel mechanisms and more effective antigastric drugs could be found. These two strategies are expected to help researchers develop more anti-gastric cancer drugs with better potency and lower side effects.

Structure, dissociation pathways and thermochemistry of some nitrogen-containing astrophysical molecules: a theoretical study

The structure, relative energies, dissociation pathways and thermochemistry of acetonitrile (CH3CN or methyl cyanide), acrylonitrile (CH2CHCN or vinyl cyanide), propionitrile (CH3CH2CN or ethyl cyanide) and their stable isomers have been studied in detail using density functional B3LYP, B3PW91 and ab initio MP2, QCISD and CCSD(T) methods. Several space missions have already confirmed the abundance of these molecules in different interstellar mediums (ISMs). The existence of related radicals, atoms and molecules are also confirmed using various IR-spectrometric techniques and that may be evolved in solar irradiation in the cold dark core TMC-1 or massive star-forming regions such as Sagittarius B2 or Oion-KL. Possible ways of fragmentation of ground state CH3NC, CH2CHNC and CH3CH2NC through different dissociation channels and their link to other isomers have been considered to justify the presence of such observed radicals in the interstellar cloud. Cyanide(-C≡N), iso-cyanide (-N = C) and imine (-C = N-H) isomeric forms have been considered here and out of these, cyanide isomers are more stable species compared to its iso-nitrile and imine form. Favourable product molecules, such as CH2 radical, C2H2, C2H4 and HCN/HNC, are considered in the dissociation channels.

Twin peaks: Matrix isolation studies of H2S·amine complexes shedding light on fundamental S-H⋯N bonding.

Noncovalent bonding between atmospheric molecules is central to the formation of aerosol particles and cloud condensation nuclei and, consequently, radiative forcing. While our understanding of O-H⋯B interactions is well developed, S-H⋯B hydrogen bonding has received far less attention. Sulfur- and nitrogen-containing molecules, particularly amines, play a significant role in atmospheric chemistry, yet S-H⋯N interactions are not well understood at a fundamental level. To help characterize these systems, H2S and methyl-, ethyl-, n-propyl-, dimethyl-, and trimethylamine (MA, EA, n-PA, DMA, and TMA) have been investigated using matrix isolation Fourier transform infrared spectroscopy and high-level theoretical methods. Experiments showed that H2S forms hydrogen bonded complexes with each of the amines, with bond strengths following the trend MA ≈ EA ≈ n-PA < TMA ≤ DMA, in line with past experimental work on H2SO4·amine complexes. However, the calculated results indicated that the trend should be MA < DMA < TMA, in line with past theoretical work on H2SO4·amine complexes. Evidence of strong Fermi resonances indicated that anharmonicity may play a critical role in the stabilization of each complex. The theoretical results were able to replicate experiment only after binding energies were recalculated to include the anharmonic effects. In the case of H2SO4·amine complexes, our results suggest that the discrepancy between theory and experiment could be reconciled, given an appropriate treatment of anharmonicity.

Iron-nitrogen co-doped carbon nanospheres prepared by template-free melting salt-assisted pyrolysis as efficient and durable oxygen reduction catalysts

It is necessary to seek oxygen reduction reactions (ORRs) electrocatalyst that can replace commercial Pt/C for new energy conversion devices. Herein, we used molten salt-assisted pyrolysis to successfully convert small nitrogen-containing carbon molecules directly into iron-nitrogen codoped carbon nanospheres (Fe–N–Cs) without the need for external templates. Molten salts provide a solvo-like environment for the high-temperature pyrolysis of small carbon molecules and bulk oxides. Small molecules containing nitrogen and carbon are subjected to spatial domain-limiting effect, reducing volatilization in the calcination processes. Besides, the strong polarity provided by molten salts can not only dissolve bulk oxides but also prevent free metal atoms from gathering again to form particles or clusters. The synthesized Fe–N–Cs exhibit excellent ORR activity. The half wave potential (E1/2, 0.67 V vs. RHE) in acidic solution is almost equivalent to Pt/C. Furthermore, Fe–N–Cs have the ability to prevent methanol poisoning and its stability is strong.

Insight into the Role of NH3/NH4+ and NOx/NO3- in the Formation of Nitrogen-Containing Brown Carbon in Chinese Megacities.

Particulate brown carbon (BrC) plays a crucial role in the global radiative balance due to its ability to absorb light. However, the effect of molecular formation on the light absorption properties of BrC remains poorly understood. In this study, atmospheric BrC samples collected from six Chinese megacities in winter and summer were characterized through ultrahigh-performance liquid chromatography coupled with Orbitrap mass spectrometry (UHPLC-Orbitrap MS) and light absorption measurements. The average values of BrC light absorption coefficient at a wavelength of 365 nm (babs365) in winter were approximately 4.0 times higher than those in summer. Nitrogen-containing organic molecules (CHNO) were identified as critical components of light-absorbing substances in both seasons, underscoring the importance of N-addition in BrC. These nitrogen-containing BrC chromophores were more closely related to nitro-containing compounds originating from biomass burning and nitrogen oxides (NOx)/nitrate (NO3-) reactions in winter. In summer, they were related to reduced N-containing compounds formed in ammonia (NH3)/ammonium (NH4+) reactions. The NH3/NH4+-mediated reactions contributed more to secondary BrC in summer than winter, particularly in southern cities. Compared with winter, the higher O/Cw, lower molecule conjugation indicator (double bond equivalent, DBE), and reduced BrC babs365 in summer suggest a possible bleaching mechanism during the oxidation process. These findings strengthen the connection between molecular composition and the light-absorbing properties of BrC, providing insights into the formation mechanisms of BrC chromophores across northern and southern Chinese cities in different seasons.

Chiral Aldehyde Catalysis-Enabled Asymmetric α-Functionalization of Activated Primary Amines.

ConspectusThe development of catalytic activation modes provides a reliable and effective platform for designing new enantioselective reactions and preparing chiral molecules with diverse structures. Chiral aldehyde catalysis is an attractive concept in asymmetric catalysis, which utilizes a chiral aldehyde catalyst to promote the asymmetric hydroamination of allylic amines, the asymmetric α-functionalization of primary amines, or the asymmetric transamination of α-keto esters. Typically, the chiral aldehyde-catalyzed asymmetric α-functionalization of primary amines provides an efficient and straightforward method for the synthesis of α-functionalized chiral amines, which does not require any additional protection or deprotection manipulations of the amine group. However, achieving catalytic stereoselective transformations with high efficiency and enantioselectivity by this strategy has remained an intractable challenge.This Account summarizes our endeavors in the development and application of chiral aldehyde catalysis. Using a chiral aldehyde as a catalyst, we reported the catalytic asymmetric α-C alkylation of 2-aminomalonate with 3-indolylmethanol in 2014, which represents the first chiral aldehyde-catalyzed asymmetric α-functionalization of an activated primary amine. Subsequently, several axially chiral aldehyde catalysts were continuously prepared by using chiral BINOL as the starting material, and their applications in asymmetric synthesis were explored. On the one hand, they were used as organocatalysts to realize the various transformations of α-amino acid esters, such as asymmetric 1,4-addition toward conjugated enones/α,β-unsaturated diesters and cyclic 1-azadienes as well as asymmetric α-arylation/allylation and benzylation with corresponding halohydrocarbons. Notably, taking advantage of the difference in the distribution of catalytic sites between two chiral aldehyde catalysts, we disclosed chiral aldehyde-catalyzed diastereodivergent 1,6-conjugated addition and Mannich reactions. On the other hand, the potential for the cooperative catalysis of a chiral aldehyde with a transition metal has also been demonstrated. Enabled by the combination of a chiral aldehyde, a palladium complex, and a Lewis acid, the enantioselective α-allylation of amino acid esters with allyl alcohol esters was established. Moreover, the ternary catalytic system has been successfully used for the α-functionalization of amino acid esters with 1,3-dienes, allenes, allenylic alcohol esters, 1,3-disubstituted allyl alcohol esters, and arylmethanol esters as well as the asymmetric cascade Heck-alkylation reaction. The combination of a chiral aldehyde and nickel complex allows for the asymmetric α-propargylation of amino acid esters with propargylic alcohol esters and provides excellent enantioselectivities. These transformations provide a large library of optically active amines and amino acids. With those chiral amino acid esters as key building blocks, the synthesis or formal synthesis of multiple natural products and biologically significant unnatural molecules was accomplished. This includes the stereodivergent synthesis of natural pyrrolizidine alkaloid NP25302 and the formal synthesis of natural product (S)-hypoestestatin 1 and manzacidin C, clinical candidate compound (+)-AG-041R, and somatostatin mimetics. It is fully anticipated that chiral aldehyde catalysis will soon witness rapid expansion both in the development of novel asymmetric transformations and in innovative applications for constructing optically active nitrogen-containing molecules with significant values.

A Pd-Catalyzed Annulation Strategy to Linearly Fused Functionalized N-Heterocycles.

Linearly fused polycyclic piperidines represent common substructures in natural products and biologically active small molecules. We have devised a Pd-catalyzed annulation strategy to these compounds that converts readily available 2-tetralones and indanones into these scaffolds with the potential for control of both enantio- and diastereoselectivity. Importantly, these compounds can be chemoselectively functionalized, providing an efficient and robust methodology to these important nitrogen-containing molecules.

Bottom-up and top-down controls on Alteromonas macleodii lead to different dissolved organic matter compositions.

The effects of both bottom-up (e.g. substrate) and top-down (e.g. viral lysis) controls on the molecular composition of dissolved organic matter have not been investigated. In this study, we investigated the dissolved organic matter composition of the model bacterium Alteromonas macleodii ATCC 27126 growing on different substrates (glucose, laminarin, extracts from a Synechococcus culture, oligotrophic seawater, and eutrophic seawater), and infected with a lytic phage. The ultra-high resolution mass spectrometry analysis showed that when growing on different substrates Alteromonas macleodii preferred to use reduced, saturated nitrogen-containing molecules (i.e. O4 formula species) and released or preserved oxidized, unsaturated sulfur-containing molecules (i.e. O7 formula species). However, when infected with the lytic phage, Alteromonas macleodii produced organic molecules with higher hydrogen saturation, and more nitrogen- or sulfur-containing molecules. Our results demonstrate that bottom-up (i.e. varying substrates) and top-down (i.e. viral lysis) controls leave different molecular fingerprints in the produced dissolved organic matter.

Hydroamination of alkynes catalyzed by NHC-Gold(I) complexes: the non-monotonic effect of substituted arylamines on the catalyst activity.

Imines are valuable key compounds for synthesizing several nitrogen-containing molecules used in biological and industrial fields. They have been obtained, as highly regioselective Markovnikov products, by reacting several alkynes with arylamines in the presence of three new N-Heterocyclic carbene gold(I) complexes (3b, 4b, and 6b) together with the known 1-2b and 7b gold complexes as well as silver complexes 1-2a. Gold(I) complexes were investigated by means of NMR, mass spectroscopy, elemental analysis, and X-ray crystallographic studies. Accurate screening of co-catalysts and solvents led to identifying the best reaction conditions and the most active catalyst (2b) in the model hydroamination of phenylacetylene with aniline. Complex 2b was then tested in the hydroamination of alkynes with a wide variety of arylamines yielding a lower percentage of product when arylamines with both electron-withdrawing and electron-donating substituents were involved. Computational studies on the rate-determining step of hydroamination were conducted to shed light on the significantly different yields observed when reacting arylamines with different substituents.

Oxidation-induced and dimer-structured clusteroluminescence for simple emissive amine molecules: Mechanism of non-traditional intrinsic luminescence

Non-traditional intrinsic luminescence (NTIL) substances have received a lot of attention because of their unique fluorescence properties in recent years. However, the NTIL molecules actually do not contain any aromatic or extended π-systems, therefore the relationships between luminous structure and emissive mechanism are still extremely debatable. In view of the above problems, this paper used small molecular amines (mainly triethylamine, TEA), a basic representative of nitrogen-containing NTIL molecules, as a template to study the structure and mechanism of NTILs. By circular treatment of reflux/distillation, careful analysis of the structural characterization coupled with theoretical calculations, we demonstrated that the optical properties of TEA were strongly related to oxygen molecules. Particularly, our data indicated that oxygen molecules induced a weak hydrogen bond between TEA molecules to form a dimer structure, meanwhile, the robust TEA-dimer and oxygen molecules were through n-π electron delocalization space conjugated to form an N⋯O clusteroluminogens. This physical bonding and spatial conjugate fluorophore structure not only well explains: why such nitrogen-containing NTIL substances lack normal organic conjugate structures and exhibit abnormally bright fluorescence in the visible spectrum when exposed to oxygen molecules (a traditional organic fluorescent material quencher), but also has important implications for further elucidating some tissue biofluorescence from oxidative folding of proteins.

Nitrogen Heterocycle Synthesis through Hydride Abstraction of Acyclic Carbamates and Related Species: Scope, Mechanism, Stereoselectivity, and Product Conformation Studies.

Acyliminium ions and related species are potent electrophiles that can be quite valuable in the synthesis of nitrogen-containing molecules. This manuscript describes a protocol to form these intermediates through hydride abstractions of easily accessible allylic carbamates, amides, and sulfonamides that avoids the reversibility that is possible in classical condensation-based routes. These intermediates are used in the preparation of a range of nitrogen-containing heterocycles, and in many cases high levels of stereocontrol are observed. Specifically areas of investigation include the impact of chemical structure on oxidation efficiency, the geometry of the intermediate iminium ions, the impact of a substrate stereocenter on stereocontrol, and an examination of transition state geometry.

Dissolved organic matter cycling revealed from the molecular level in three coastal bays of China

As the widespread distributed and critical zones connecting the land and ocean systems, coastal bays are special units with semi-enclosed landforms to accommodate and process dissolved organic matter (DOM) in the context of increasing anthropogenic effects globally. However, compared to other common systems that have been paid much attention to (e.g., large river estuaries, wetlands), the roles of the coastal bays in coastal carbon cycling are less explored. To fill this knowledge gap, here we combined optical techniques and ultra-high-resolution mass spectrometry to systematically investigate the DOM chemistry of the three typical coastal bays in different nutrient levels, Xiangshan Bay, Jiaozhou Bay, and Sishili Bay, in China. Results show that terrestrial signals and anthropogenic imprints were observed in these three bays to various extents. Besides, Xiangshan Bay with a higher nutrient level had the DOM characterized by lower humification and aromaticity degree than Jiaozhou Bay and Sishili Bay, which not likely mainly resulted from the differences in the primary production or photochemical processing. Further examination reveals that microbial processing likely contributes to the differences in DOM chemistry among the three bays, as indicated by different proportions of potentially transformed nitrogen-containing molecules and relative abundances of the island of stability molecules. Considering the nutrient levels in different bays, we speculate that the lower nutrient concentrations would promote the efficiency of the microbial carbon pump (MCP), which hypothesized that heterotrophic microorganisms might contribute to the formation of marine recalcitrant organic carbon. Additionally, the enrichment of oxygen-rich compounds in the unique carboxyl-rich alicyclic molecule pool of Jiaozhou Bay and Sishili Bay suggests that the efficient MCP might preferentially form them in these two bays. This study emphasizes the importance of coordinating the land and ocean systems and controlling the nutrient discharge to coastal bays, thus, to potentially promote long-term marine carbon sequestration.

Photocatalytic Multicomponent 1,n-Carboimination with Alkyl Iodides and O-Benzoyl Oxime through EnT and XAT Processes.

In this study, we developed a strategy using commercially available alkyl iodides and O-benzoyl oxime to efficiently introduce alkyl and iminyl groups via energy transfer and halogen-atom transfer processes. We performed three-component 1,2-carboimination of olefins and four-component 1,4-carboimination across olefins and alkynes, resulting in the synthesis of over 60 nitrogen-containing molecules. Moreover, this transformation enables the synthesis of molecules with sensitive groups that were previously difficult to achieve.

Artificial Metalloenzyme-Catalyzed Enantioselective Amidation via Nitrene Insertion in Unactivated C(sp3)-H Bonds.

Enantioselective C-H amidation offers attractive means to assemble C-N bonds to synthesize high-added value, nitrogen-containing molecules. In recent decades, complementary enzymatic and homogeneous-catalytic strategies for C-H amidation have been reported. Herein, we report on an artificial metalloenzyme (ArM) resulting from anchoring a biotinylated Ir-complex within streptavidin (Sav). The resulting ArM catalyzes the enantioselective amidation of unactivated C(sp3)-H bonds. Chemogenetic optimization of the Ir cofactor and Sav led to significant improvement in both the activity and enantioselectivity. Up to >700 TON and 92% ee for the amidation of unactivated C(sp3)-H bonds was achieved. The single crystal X-ray analysis of the artificial nitrene insertase (ANIase) combined with quantum mechanics-molecular mechanics (QM-MM) calculations sheds light on critical second coordination sphere contacts leading to improved catalytic performance.

Surface Treatment of Biochar—Methods, Surface Analysis and Potential Applications: A Comprehensive Review

In recent years, biochar has emerged as a remarkable biosourced material for addressing global environmental, agricultural, biomedical, and energy challenges. However, the performances of biochar rest in part on finely tuning its surface chemical properties, intended to obtain specific functionalities. In this review, we tackle the surface treatment of biochar with silane and other coupling agents such as diazonium salts, titanates, ionic/non-ionic surfactants, as well as nitrogen-containing (macro)molecules. We summarize the recent progress achieved mostly in the last five years and correlate the nature and extent of functionalization to eye-catchy end applications of the surface-engineered biochar.