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New methylamine derivatives with 1,2-azole fragments (phenylisoxazole, p-tolylisoxazole, 2,5-dimethylphenylisoxazole and 4,5-dichloroisothiazole) and their palladium complexes were synthesized. It was shown that palladium complexes with the obtained N-methyl-1-(1,2-azol-3-yl)methylamine exhibit high catalytic activity in the Suzuki reaction in aqueous medium.

The fast progress of lab-scale perovskite solar cells makes the problem of upscaling of perovskite thin-film deposition more and more acute; therefore, the development of new methods for perovskite deposition is highly desired. In this work, we proposed a new solution-free preparation approach for hybrid perovskite films based on the in situ generation of methylammonium iodide from methylamine and iodine vapors in the presence of an organic reducing agent conjugated with a redox process of metallic lead conversion with iodine vapor. At first, we demonstrated that either metallic lead or lead iodide powders can readily react with the solution of methylamine and iodine in the presence of isopropyl alcohol acting as a reducing agent, resulting in a phase-pure polycrystalline CH3NH3PbI3 perovskite. A possible mechanism of underlying chemical processes has been proposed. In order to convert the predeposited thin films of metallic lead to CH3NH3PbI3 perovskite, a protocol of sequential treatment by iodine and methylamine vapors was proposed. Finally, we revealed the optimal conditions of processing, which were proven to be facile and robust for the sake of the better control of perovskite grain morphology.

The role of methanesulfonic acid (MSA) in atmospheric new particle formation remains highly uncertain. Using state-of-the-art computational methods, we study the electrically neutral (MSA)(0-2)(base)(0-2) clusters, with base = ammonia (A), methylamine (MA), dimethylamine (DMA), trimethylamine (TMA), and ethylenediamine (EDA). The cluster configurations are obtained using the ABCluster program and the number of initial cluster configurations is reduced based on PM7 calculations. Thermochemical parameters are calculated using the quasi-harmonic approximation based on the omega B97X-D/6-31++G(d,p) cluster structures and vibrational frequencies. The single point energies are calculated at the DLPNO-CCSD(T-0)/aug-cc-pVTZ level of theory. We find that MSA shows a different interaction pattern with the bases compared to sulfuric acid and does not simply follow the basicity of the bases for these small clusters. In all cases, we find that the MSA-base clusters show very low cluster formation potential, indicating that electrically neutral clusters consisting solely of MSA as the clustering acid are most likely not capable of forming and growing under realistic atmospheric conditions.

L-amino acids (L-AAs) play different important roles in the physiology of all living organisms. Their chiral counterparts, D-amino acids (D-AAs) are increasingly being recognized as essential molecules in many biological systems. Secondary amino acids with cyclic structures, such as prolines, exhibit conformational rigidity and thus unique properties in the structural and protein folding. Despite their widespread occurrence, much less attention was paid to their chiral analysis, particularly when the minor, typically D-enantiomer, is present in low amounts in a complex biological matrix. In this paper, a cost-effective, chiral GC-MS method is described for capillary Chirasil-L-Val separation of nine cyclic secondary amino acid enantiomers with four-, five-, and six-membered rings, involving azetidine-2-carboxylic acid, pipecolic acid, nipecotic acid, proline, isomeric cis/trans 3-hydroxy, 4-hydroxyproline, and cis/trans-5-hydroxy-L-pipecolic acid in the excess of its enantiomeric antipode. The sample preparation involves in-situ derivatization with heptafluorobutyl chloroformate, simultaneous liquid-liquid micro-extraction into isooctane followed by amidation of the arising low-polar derivatives with methylamine, an evaporation step, re-dissolution, and final GC-MS analysis. The developed method was used for analyses of human biofluids, biologically active peptides containing chiral proline constituents, and collagen.

The effect of sulfuric acid (SA) concentrations on heterogeneous reactions of amines such as methylamine (MA), dimethylamine (DMA), and trimethylamine (TMA) at the air-particle interface is investigated using combined classical molecular dynamics, Born-Oppenheimer molecular dynamics, and quantum chemical calculations. The results show that the mixtures of these amine vapors can accumulate at the air-particle interface and then participate in two types of heterogeneous reactions depending on the SA concentrations in the aqueous particles. At high SA concentrations, amines are neutralized by H3O+ and form ammonium salts within only a few picoseconds. At low SA concentrations, amines mainly proceed by hydrolysis reactions and produce ionic pairs of ammonium and OH-. However, the formed ionic pair is extremely unstable, and the reverse reaction takes place. Considering that the salt conversion time scales of amines at high SA concentrations are 2.5-15 times faster than those at low SA concentration, amine accumulation at high acidity particles is more favored.

The first continuous flow process was developed to synthesize N-methyl secondary amines from alkyl mesylates and epoxides via a nucleophilic substitution using aqueous methylamine. A variety of N-m...

BACKGROUND: Persimmon tannin, extracted from young astringent persimmons, is a cheap waste biomass material. The abundant phenolic hydroxyl groups in persimmon tannin are known to display excellent affinity to Mo(VI). In addition, ligands containing N donor atoms, as brilliant adsorption groups, can strongly interact with Mo(VI) when the groups are protonated under acidic conditions. Therefore, the introduction of nitrogen‐containing groups in persimmon tannin may be an effective method to improve the recovery capacity of biosorbent for Mo(VI) in aqueous solution. In this work, a series of adsorbents were prepared by immobilizing ethylenediamine or methylamine on the surface of persimmon tannin. RESULTS: Due to the abundant nitrogen‐containing groups and hydroxyl groups, the ethylenediamine modified persimmon tannin exhibited excellent maximum uptake capacity to Mo(VI) (478.02 mg·g⁻¹), which was superior to that of methylamine modified persimmon tannin. Further, the results of XPS and FT‐IR confirmed that Mo(VI) was adsorbed on the hydroxyl‐assisted nitrogen‐containing group modified persimmon tannin via coordination and electrostatic interaction. CONCLUSION: Furthermore, 99% of Mo(VI) was selectively recovered from coexisting ions by en‐CPT under appropriate acidic conditions (pH 1). Pseudo‐second‐order kinetic model best represented the adsorption process of Mo(VI) onto the en‐CPT. The adsorption equilibrium was achieved in a relatively short time (no more than 1 h). High recovery efficiency and excellent selective adsorption made the en‐CPT an ideal candidate for Mo(VI) recovery in practical applications. © 2020 Society of Chemical Industry (SCI)

The formation and decomposition kinetics of N-chloro-N-methyl amino acids were studied to predict the fate and impact of these compounds in water treatment technologies and biological systems. These compounds form in fast second-order reactions between N-methyl amino acids and hypochlorous acid. The comparison of the activation parameters for the reactions of N-methyl substituted and nonsubstituted branched-chain amino acids reveals the transition-state features less organized structure and stronger bonds between the reactants in the reactions with the N-methyl derivatives. This is due to a combined positive inductive effect of the N-methyl group and the alkyl side chain as well as to the steric effects of the substituents. N-Methyl-N-chloro amino acids decompose much faster than the nonsubstituted compounds. The reaction rates do not depend on the pH, and the same final product is formed in the entire pH range. N-Chlorosarcosine is an exception, as it decomposes via competing paths, kdobs = kd + kdOH[OH-], yielding different final products. This feature is most likely due to the lack of an alkyl substituent on the α-carbon atom. Under physiological pH, aldehydes and methylamine form in these reactions, which are not particularly toxic.

Summary The studies of perovskite film in the perovskite solar cells (PSCs) mainly focus on their crystallization and growth, but the reactions that happen in the precursor solutions are still not very clear, which is leading to the bad reproducibility for high-efficient devices. We demonstrated that, in the methylammonium- and formamidinium-mixed organic cation perovskite solution, the methylamine molecule could be first generated from the deprotonation of methylammonium iodide, and then condensate with formamidinium iodide to form N-methyl formamidinium iodide and N, N′-dimethyl formamidinium iodide. The triethyl borate was carried out as a stabilizer to restrain the deprotonation of methylammonium iodide in the precursor solutions, resulting in the elimination of the impurity phase in perovskite films. We think that the introduction of stabilizer in the perovskite precursor solution will become a common strategy for mixed-organic-cation PSCs in the future to improve the reproducibility and efficiency.

The biocatalytic synthesis of amides from carboxylic acids and primary amines in aqueous media can be achieved using the ATP-dependent amide bond synthetase McbA, via an adenylate intermediate, using only 1.5 equiv of the amine nucleophile. Following earlier studies that characterized the broad carboxylic acid specificity of McbA, we now show that, in addition to the natural amine substrate 2-phenylethylamine, a range of simple aliphatic amines, including methylamine, butylamine, and hexylamine, and propargylamine are coupled efficiently to the native carboxylic acid substrate 1-acetyl-9H-β-carboline-3-carboxylic acid by the enzyme, to give amide products with up to >99% conversion. The structure of wild-type McbA in its amidation conformation, coupled with modeling and mutational studies, reveal an amine access tunnel and a possible role for residue D201 in amine activation. Amide couplings were slower with anilines and alicyclic secondary amines such as pyrrolidine and piperidine. The broader substrate specificity of McbA was exploited in the synthesis of the monoamine oxidase A inhibitor moclobemide, through the reaction of 4-chlorobenzoic acid with 1.5 equiv of 4-(2-aminoethyl)morpholine, and utilizing polyphosphate kinases SmPPK and AjPPK in the presence of polyphosphoric acid and 0.1 equiv of ATP, required for recycling of the cofactor.

Protonated forms of layered perovskite-like titanates HLnTiO4 (Ln = La, Nd), relating to the Ruddlesden-Popper phases, have been used to yield inorganic-organic hybrids with the simplest representatives of amines (methylamine), alcohols (methanol), aminoalcohols (monoethanolamine) as well as n-butylamine. The possibility of the synthesis of the hybrids is studied in a wide range of conditions using both standard laboratory techniques and solvothermal/solvothermal-microwave methods. It is established that only methylamino derivatives may be synthesized in a single-phase form by a direct reaction between protonated titanates and the corresponding organic compound whereas pure n-butylamino, methanolic and monoethanolamino hybrids may be obtained on the basis of methylamino ones. For all the hybrids synthesized structure, quantitative composition, morphology and a type of a bond between inorganic and organic parts are discussed by means of powder XRD, Raman, IR and NMR spectroscopy, STA, elemental CHN analysis and SEM.

Organic–inorganic halometallates are a very promising class of compounds within the more general domain of organic–inorganic hybrid materials. The efficient approach for creating new hybrid halometallate salts is the design and use of monovalent organic cations, where the size, shape and electronic structure can be varied over wide limits, for introducing useful properties into hybrid structures. Therefore, we have prepared two new chlorometallate salts [L′]2[ZnCl4] (1) and [L′]n[PbCl3]n∞ (2) with 2-methyl-imidazo[1,5-a]pyridinium cations [L′]+ formed as a result of the oxidative cyclocondensation between formaldehyde, methylamine and 2-pyridinecarbaldehyde in water media. While the tetrahedral ZnCl42− anions show no connectivity in 1, the hybrid exhibits a pseudo-layered structure with organic and inorganic sublattices arranged parallel to the bc plane. In the crystal of 2, stacks of the aromatic cations alternate with one-dimensional stepwise chloroplumbate wires along the a direction. The use of PdCl2 as a source of metal ions in the same synthetic procedure did not result in a hybrid tetrachloropalladate but produced the cationic complex [PdClL′′]Cl (3) with trapped bis-hemiaminal L′′, an intermediate to imine. In the solid state, 3 with two stereogenic centres should be seen as a 50 : 50 racemic mixture of two optically-active compounds but it shows a meso structure in DMSO solution. Broad emission with a maximum at around 386 nm of 1 and 2 in solution (λex = 275 nm) originates from the organic component. Upon excitation at 214 nm, crystalline powder samples of 1 and 2 exhibit intense sky blue-light photoluminescence.

All-inorganic CsPbX3 (X = I, Br) perovskites without organic component are promising for long-term stability but face main challenges of facile fabrication and phase stability. Here we discover a general organic methylamine acetate salt mediated growth method to deposit high quality phase pure and stable CsPbX3 (X = I, Br) perovskite films via a novel precursor consisting of stoichiometric cesium acetate (CsAc), methylamine halide (MAX) and lead halide (PbX2). Interestingly, these organic salts of CsAc and MAX could efficiently promote the crystallization process especially lower the crystallization temperature, but do not introduce the incorporation of organic MA cation into all-inorganic CsPbX3 perovskites. These phase pure and stable CsPbX3 perovskites with tunable band gaps can be fabricated into high efficiency photovoltaics. Our organic salt mediated growth of all-inorganic perovskite not only reveals the all-inorganic CsPbX3 perovskite’s unique crystal growth mechanism but also demonstrates their promising application for photovoltaics.

Synergistic effects between different bases can greatly enhance atmospheric sulfuric acid (SA)-base cluster formation. However, only the synergy between two base components has previously been investigated. Here, we extend this concept to three bases by studying large atmospherically relevant (SA)3(base)3 clusters, with the bases ammonia (A), methylamine (MA), dimethylamine (DMA), trimethylamine (TMA) and ethylenediamine (EDA). Using density functional theory—ωB97X-D/6-31++G(d,p)—we calculate the cluster structures and vibrational frequencies. The thermochemical parameters are calculated at 29,815 K and 1 atm, using the quasi-harmonic approximation. The binding energies of the clusters are calculated using high level DLPNO-CCSD(T0)/aug-cc-pVTZ. We find that the cluster stability in general depends on the basicity of the constituent bases, with some noteworthy additional guidelines: DMA enhances the cluster stability, TMA decreases the cluster stability and there is high synergy between DMA and EDA. Based on our calculations, we find it highly likely that three, or potentially more, different bases, are involved in the growth pathways of sulfuric acid-base clusters.

A combined experimental–computational study of hydrocarbon oxidation by the MnIV-oxo complex of the neutral, pentadentate N4py ligand [N,N-bis(2-pyridylmethyl)-N-bis(2-pyridyl)methylamine] offers s...

Three amine-modified Merrifield resins (AMMRs) were synthesized with ethane diamine, methylamine and dimethylamine to assess the impact of amine group on SO2 adsorption under low SO2 concentration. The dimethylamine-modified Merrifield resin (DMAMR) grafting with tertiary amine groups showed the greatest SO2 adsorption compared with ethane diamine-modified Merrifield resin (EDAMR) and methylamine-modified Merrifield resin (MAMR). Different amine groups had different reaction mechanisms with SO2. It was much easier for SO2 to form noncovalent charge transfer complex with tertiary amine group than the zwitterion and ion/counterion products with primary and secondary amine groups under dry condition. The noncovalent charge transfer complex had a relatively weaker thermostability than the zwitterion and ion/counterion products. As the temperature increased from 25 °C to 75 °C, the SO2 adsorption capacity on DMAMR decreased by 78.92%, which was much higher than that of EDAMR and MAMR (63.77% and 63.41% respectively). As SO2 concentration increased from 40 ppm to 100 ppm, significant increase (∼100%) in SO2 adsorption capacity was observed. Lower SO2 flow rate led to a more sufficient reaction between SO2 and amine groups, resulting the increase in SO2 adsorption capacities. Water vapor enhanced the SO2 adsorption performance of AMMRs significantly due to the formation of salt. However, it was more difficult for tertiary amine group to react with SO2 in the presence of water due to its relatively weaker basicity. DMAMR showed a greater regeneration performance than EDAMR and MAMR under dry and humid condition.

The high-molecular weight polycyclic aromatic hydrocarbons (PAHs) pyrene and typical long chain alkane n -hexadecane are both difficult to degrade. In this study, n -hexadecane and pyrene degrading strain Rhodococcus sp. T1 was isolated from oil contaminated soil. Strain T1 could remove 90.81% n -hexadecane (2 vol%) and 42.79% pyrene (200 mg·L − 1 ) as a single carbon within 5 days, respectively. Comparatively, the degradation of pyrene increased to 60.63%, but the degradation of n -hexadecane decreased to 87.55% when these compounds were mixed. Additionally, identification and analysis of degradation metabolites of Rhodococcus sp. T1 in the above experiments showed that there were significant changes in alanine, methylamine, citric acid and heptadecanoic acid between sole and dual substrate degradation. The optimal conditions for degradation were then determined based on analysis of the pH, salinity, additional nutrient sources and liquid surface activity. Under the optimal conditions of pH 7.0, 35 °C, 0.5% NaCl, 5 mg·L − 1 of yeast extract and 90 mg·L − 1 of surfactant, the degradation increased in single or dual carbon sources. To our knowledge, this is the first study to discuss metabolite changes in Rhodococcus sp. T1 using sole substrate and dual substrate to enhance the long-chain alkanes and PAHs degradation potential.

An ionic-liquid additive of methylammonium acetate (MAAc) is introduced in the lead iodide (PbI2) precursor solution to enhance the morphology and photovoltaic performances of perovskite film through a two-step spin-coating method. The introduction of MAAc at the first step spin-coating process can produce a mixed perovskite of MAPbI3-x(Ac)x, which is capable of generating uniform perovskite film with enough thickness, large grain size, and suitable optical band gap at the second step spin-coating process as a function of crystal seed, resulting in highly efficient generation and transportation of electron for the perovskite solar cell (PSC). As a result, the PSC with 9% MAAc (molar ratio) yields efficiency of 17.07%, which is higher than that of the PSC without MAAc (14.54%). These effects of MAAc in the PbI2 precursor solution on the morphology and photovoltaic performances of perovskite film highlights the potential application of the methylamine compounds as the additives in the cost-effective PSC.

Low molecular weight (LMW) compounds are key intermediates in organic matter degradation and their metabolism supports a diverse microbial community in anoxic sediments. Much remains to be learned about the metabolic pathways and turnover rates of LMW compounds as well as the factors that influence their metabolism in the environment. We studied the microbial metabolism of acetate, methanol and methylamine in sediments from Northern Gulf of Mexico to elucidate their role as energy and carbon sources for microorganisms mediating terminal metabolic processes and to constrain the importance of C1 and C2 metabolism in the sedimentary carbon cycle. In terms of carbon flow, methanogenesis was a minor process in sulfate-rich sediments; acetate and methanol were oxidized primarily by non-methanogenic heterotrophs as an energy source. A large fraction of utilized acetate (20–76%) was assimilated into biomass, suggesting that acetate was a significant biomass-building source. In situ thermodynamic calculations suggested the utilization of acetate and methanol by sulfate-reducing bacteria was more favorable than the utilization by methanogens, consistent with the observed higher oxidation rates than methanogenesis rates as well as results from inhibitor experiments employing 2-bromoethanesulfonate and molybdate. Methylamine, by contrast, was utilized for methane production (up to 100%), but its utilization was not limited to methanogens. At an organic-poor deep-sea site, elevated acetate and methanol oxidation rates in the absence of sulfate-reducing and methanogenic activity indicated that metabolism of LMW compounds was coupled to other electron accepting processes, such as denitrification. Heterotrophic carbon assimilation was an important pathway for generating biomass at this site, as evidenced by comparable rates of acetate assimilation to bicarbonate incorporation. The oxidation and assimilation rates of LMW compounds generally decreased with sediment depth, following the trend of organic carbon degradation rates. Environmental factor, such as temperature but not pressure, affected the metabolism of LMW compounds; the oxidation of acetate, methanol and methylamine exhibited distinct responses to changes in temperature. In seep sediments, the oxidation of acetate and methanol accounted for 5% and 0.9%, respectively, of the total organic carbon oxidation. Collectively, this assessment of C1 and C2 LMW compound utilization shows that these compounds serve as energetic substrates to fuel methanogens, sulfate reducers and other microbes.

A simple and reliable method of preparing high-quality perovskite layers is essential for the high photovoltaic performance of perovskite solar cells. Here, a new low-boiling-point solvent system composed of methylamine solution in ethanol and tetrahydrofuran is designed for methylammonium lead iodide precursor solutions. Concentrated methylammonium lead iodide precursor solutions with a concentration of 2.1 M are obtained, and smooth and compact methylammonium lead iodide films with an area of up to 600 cm2 are prepared directly by one-step spin-coating or blade-coating the precursor solution at room temperature. The rapid evaporation of the solvent and strong interaction between methylamine and methylammonium lead iodide lead to a high crystal nucleus density and intermediate-free crystallization path, and consequently result in a compact and smooth film. The high-quality methylammonium lead iodide films show excellent photovoltaic performance in conventional mesoporous solar cells with efficiencies of 20.0% (0.1 cm2) and 15.6% (10 cm2). Because of the low cost and ease of operation, the solvent system developed in this work is promising both in the laboratory and for future industrialization.

N,N-Diphenylamino- and N,N-dicyclohexylamino-substituted dichlorophosphane W(CO)5 complexes 1a,b were used to generate thermally very labile Li/Cl phospinidenoid W(CO)5 complexes 2a,b. The formation of transient complex 2a was confirmed via low-temperature 31P{1H} NMR spectroscopy, but further strong evidence for the formation of transient complexes 2a,b was obtained from reactions with methanol and methylamine as formal E–H insertions (E = O, N) furnished complexes 3a,b and 4a. By using toluene in the absence of donor ligands, the primarily nucleophilic complexes 2a,b were converted into electrophilic terminal phosphinidene complexes 5a,b which was deduced from specific trapping reactions using tolane, 1-pentene and 1-hexene and thus obtained 1H-phosphirene 6 and phosphirane complexes 7 and8. The state-of-the-art DFT calculations reveal insights into the possible reaction pathways and exclude a direct reaction of 2a,b with alkene trapping reagents.

The development and optimization of an analytical method for the detection and identification of reactive metabolite of organochlorine chemical warfare agent nitrogen mustards (NMs), 2-[(2-chloroethyl)(alkyl)amino]ethanol (CEAAE), known as half nitrogen mustard, in blood samples is presented, herein. In this study, half nitrogen mustards in plasma are presented as a new and unambiguous biomarker of NM exposure since the fully hydrolyzed product, i.e., amino alcohols, are common industrial chemicals that can be present as such without getting exposed to NMs. Thus, the detection of half nitrogen mustard as a biomarker holds great significance for verification by the Chemical Weapon Convention (CWC) and will also be helpful in understanding the pharmacokinetics of NM-based chemotherapeutic pro-drugs. To the best of our knowledge, this is the first report on the detection of half nitrogen mustards in any matrice, including plasma. A very simple sample preparation protocol was developed for its extraction from plasma samples. Heptafluorobutyrylation and gas chromatography-tandem mass spectrometry in the positive chemical ionization mode were developed for the detection and identification of halfNMs. The developed method has shown excellent analytical figures of merits such as a wide range of linearity (1.0–50 ng mL−1), low limit of detection (0.3–0.5 ng mL−1), and low limit of quantification (1.0 ng mL−1). The interday and intraday reproducibilities were also less than 15%. The developed method was successfully applied to real-world samples; in vitro human plasma was spiked with ∼1 ng mL−1 of all the NMs and in vivo studies were done with rats intravenously exposed to 1 × LD50 of bis(2-chloroethyl)methylamine (HN2).

Owing to the poor fragmentation efficiency caused by the lack of a positively charged basic group at the C-termini of peptides, the identification of nontryptic peptides in classical proteomics is known to be less efficient. Particularly, attaching positively charged basic groups to C-termini via chemical derivatizations is known to be able to enhance their fragmentation efficiency. In this study, we introduced a novel strategy, C-termini sequential amidation reaction (CSAR), to improve peptide fragmentation efficiency. By this strategy, C-terminal and side-chain carboxyl groups were firstly amidated by neutral methylamine (MA), and then C-terminal amide bonds were selectively deamidated through peptide amidase while side-chain amide bonds remained unchanged, followed by the secondary amidation of C-termini via basic agmatine (AG). We optimized the amidation reaction conditions to achieve the MA derivatization efficiency of >99% for side-chain carboxyl groups and AG derivatization efficiency of 80% for the hydrolytic C-termini. We applied CSAR strategy to identify bovine serum albumin (BSA) chymotryptic digests, resulting in the increased fragmentation efficiencies (improvement by 9-32%) and charge states (improvement by 39-52%) under single or multiple dissociation modes. The strategy described here might be a promising approach for the identification of peptides that suffered from poor fragmentation efficiency.

Carbon fiber ionization (CFI)-mass spectrometry (MS) is an ambient technique that can be used to detect samples in gas, liquid, and solid forms simply by using a piece of carbon fiber as the ionization emitter. Reactive MS can be performed to selectively detect target analytes by conducting fast reactions during ionization. Most ambient ionization MS techniques used to monitor chemical reactions are limited to liquid-phase reactions. Herein, we develop reactive CFI-MS to be a suitable tool for monitoring of reaction products derived from volatile unsaturated hydrocarbons in the gas phase. Hydroamination is a fast reaction that can form a carbon-nitrogen bond through the addition of an amine to unsaturated hydrocarbons. In this study, reactive CFI-MS was used to selectively characterize aroma molecules, which are unsaturated hydrocarbons derived from plants, through hydroamination. A piece of carbon fiber was placed close (~ 1 mm) to the inlet of the mass spectrometer and deposited with dried methylamine. The sample in either liquid or solid form was placed underneath the carbon fiber. The volatiles derived from the sample reacted with amine on the carbon fiber were simultaneously determined once the mass spectrometer was switched on. For proof of concept, ethylene glycol dimethacrylate, which has double bonds and is highly volatile, was initially selected as the model sample to demonstrate the feasibility of using reactive CFI-MS to detect its hydroamination derivative. Banana, garlic, and ginger, which possess aroma molecules with unsaturated hydrocarbons, were selected as real-world samples. Graphical abstract.

Protein arginine methylation regulates diverse biological processes including signaling, metabolism, splicing, and transcription. Despite its important biological roles, arginine methylation remains an understudied post-translational modification. Partly, this is because the two forms of arginine dimethylation, asymmetric dimethylarginine (ADMA) and symmetric dimethylarginine (SDMA), are isobaric and therefore indistinguishable by traditional mass spectrometry techniques. Thus, there exists a need for methods that can differentiate these two modifications. Recently, it has been shown that the ADMA and SDMA can be distinguished by the characteristic neutral loss (NL) of dimethylamine and methylamine, respectively. However, the utility of this method is limited because the vast majority of dimethylarginine peptides do not generate measurable NL ions. Here, we report that increasing the normalized collision energy (NCE) in a higher-energy collisional dissociation (HCD) cell increases the generation of the characteristic NL that distinguish ADMA and SDMA. By analyzing both synthetic and endogenous methyl-peptides, we identify an optimal NCE value that maximizes NL generation and simultaneously improves methyl-peptide identification. Using two orthogonal methyl peptide enrichment strategies, high pH strong cation exchange (SCX) and immunoaffinity purification (IAP), we demonstrate that the optimal NCE increases improves NL-based ADMA and SDMA annotation and methyl peptide identifications by 125% and 17%, respectively, compared to the standard NCE. This simple parameter change will greatly facilitate the identification and annotation of ADMA and SDMA in mass spectrometry-based methyl-proteomics to improve our understanding of how these modifications differentially regulate protein function.

The analysis of breath VOC biomarkers is an efficient method for the early diagnosis of lung cancer. In this work, the zirconium UiO-66 was post-synthetically modified by using methylamine (MA), ethylenediamine (ED) and N,N′-dimethylethylenediamine (MMEN), respectively. The modified UiO-66 materials were thoroughly characterized, including PXRD, FTIR, TGA, physical adsorption at 77 ​K by nitrogen and photoluminescence analysis. The sensing properties of the modified UiO-66 materials toward the selected five potential breath VOC biomarkers were investigated. Results showed that after modification, the BET surface area and total pore volume all decreased, and followed the order: UiO-66 ​> ​UiO-66-MA ​> ​UiO-66-MMEN ​> ​UiO-66-ED. Furthermore, the N–H group was successfully grafted into the modified UiO-66 samples. In comparison with UiO-66, the fluorescence intensities of UiO-66-MA, UiO-66-ED and UiO-66-MMEN toward hexanal, styrene and isoprene all obviously increased, while the fluorescence intensities of the modified UiO-66 materials toward 1-propanol and ethylbenzene all decreased a lot, accompanied by the frequency shift. In addition, the LOD of hexanal on UiO-66-MA was calculated to be as low as 12 ​ppm, which was obviously lower than that of UiO-66 (31 ​ppm). The fluorescence quenching of hexanal was mainly due to the FRET mechanism. The results of this study would provide information for the development of early breath diagnosis of lung cancer.

A new efficient method for synthesizing promising heat shock protein inhibitors, N,N-dialkyl- 1-(2-alkylthiopyrimidin-4-yl)piperidin-4-amines, by the reaction of 2-alkyl-4-chlorothiouracils with 4-(N-alkyl-N-methylamino)piperidines was developed. 2-Alkyl-4-chlorothiouracils were synthesized by alkylation of 2-thiouracil with alkyl iodides and subsequent treatment of the intermediates with POCl3. 4-(N-Alkyl-N-methylamino)piperidines were prepared by reductive amination of 1-(tert-butoxycarbonyl)-4-piperidinone with methylamine followed by treatment of the intermediate with the appropriate aldehydes.

Acidities and basicities are normally rationalized with the help of concepts like inductive and delocalization effects. There are, however, difficulties in estimating these quantities for most of systems. In this work, energy decomposition analysis has been used to interpret the basicity of a series of nitrogen compounds. With the help of CMOEDA (LMOEDA) partitioning scheme, the increase of basicities with the increasing alkyl chain length of amines was attributed mainly to polarization (orbital rearrangement) interactions. The variation in basicites among cyclic amines, which has been interpreted as a consequence of geometry/hybridization, was also attributed mainly to polarization, with electrostatic interactions also playing an important role in some cases. The effect of the substituent (electron attractor or electron donor) on the basicity of aniline was studied as a model to aromatic compounds. In this case, electrostatic is the most important factor. Finally, some simple conjugated nitrogen compounds were investigates, namely, formamide, thioformamide and enamine. The smaller basicity of formamide compared to methylamine is attributed mainly to electrostatic interactions, as is explained in detail. Geometrical changes (from a planar to a pyramidal structure) plays a secondary role. Combination of EDA results with a solvent model allows the interpretation of p K a values.

Aims & Objective: An efficient procedure for the synthesis of pyrido[2,1-a]isoquinoline derivatives in excellent yields was investigated using catalyst-free multicomponent reaction of phthaladehyde, methylamine, activated acetylenic compounds, alkyl bromides and triphenylphosphine in water under ultrasonic irradiation at room temperature. In addition, Diels- Alder reactions of pyrido[2,1-a]isoquinoline derivatives with activated acetylenic compounds under ultrasonic irradiation are investigated in two procedures. The advantages of this procedure compared to report methods are short time of reaction, high yields of product, easy separation of product, clean mixture of reaction and green media for performing reaction. In addition, because of having isoquinoline core in synthesized compounds, in this research antioxidant activity of some synthesized compounds was studied. Materials and Methods: To a stirred mixture of phthalaldehyde 1 (2 mmol) and methylamine 2 (2 mmol) in water (3 mL) under ultrasonic irradiation was added to activated acetylenic compounds 4 after 20 min. Alkyl bromide 3 and triphenylphosphine 5 react in another pot in water (3 mL) under ultrasonic irradiation for 15 min. After this time, this mixture was added to the first pot. After completion of the reaction, the solid residue was separated by filtration and washed with Et2O to afforded pure title compound 6. Results: In this work, generation of pyrido[2,1-a]isoquinoline derivatives 6 are performed using phthalaldehyde 1, methylamine 2, α-halo substituted carbonyls 3, activated acetylenic compounds 4 and triphenylphosphine 5 in water under ultrasonic irradiation condition at room temperature in excellent yield at short time. Conclusion: In summary, multicomponent reaction of phthaladehyde, methylamine, activated acetylenic compounds, alkyl bromides and triphenylphosphine in water under ultrasonic irradiation at room temperature produced pyrido[2,1-a]isoquinoline derivatives in excellent yields. Also, Diels-Alder reaction of pyrido[2,1-a]isoquinoline derivatives with activated acetylenic compounds and triphenylphosphine under ultrasonic irradiation is investigated in two procedures. Also, the antioxidant activities of 6a, 6c, 6g and 6i were evaluated by DPPH radical scavenging and ferric reducing power analyzes. The compounds 6a exhibit excellent DPPH radical scavenging activity and FRAP compared to synthetic antioxidants BHT and TBHQ. The chief benefits of our method are high atom economy, green reaction conditions, higher yield, shorter reaction times, and easy work-up, which agree with some principles of green chemistry.

Molecular clusters containing the selected highly oxidized molecule (HOM) C10H14O7, 2-Methyl-5-[(1S,2S,3R)-1,2,3,4-tetrahydroxybutyl]-3-furoic acid, and common trace neutral and ionic atmospheric species, such as H2SO4 , NH3, H2O, methylamine and dimethylamine molecules and airborne HSO4− and NO3− ions, have been investigated using the Density Functional Theory. Optimization of geometries have been conducted at PW91PW91 level using 6-311++G(3df,3pd) basis set. The results have been discussed in terms of structural, energetic, and atmospheric perspectives. It is shown that the C10H14O7 may impact new particle formation by forming stable hydrogen-bonded clusters with ionic and neutral species such as strongly bonded HOM-NO3− organonitrates (ONs) and HOM-HSO4− complexes and, possibly, HOMH2SO4-amine clusters.

A thorough investigation on whether a stepwise or a concerted pathway is involved in the synthesis of substituted N-benzoyl urea derivatives by reaction of substituted N-benzoylcarbamates and aliphatic/aromatic amines using density functional theory (DFT) calculations at B3LYP/6–31 + G (d,p) level of theory has been reported. The study of effects of nature of leaving group present in N-benzoylcarbamate, structure of amines, and solvents on the reaction showed that the choice of reaction mechanism involved depends upon the nature of leaving group present on N-benzoylcarbamate. The effect of structure of amine on reaction mechanism depends upon the type of leaving group present on N-benzoylcarbamate. We have also observed that the reaction between aliphatic/aromatic amine with phenyl benzoylcarbamate is thermodynamically more favorable, while a reaction between phenyl/methyl benzoylcarbamates with methylamine is more preferred. The effect of polar solvent water and non-polar solvent toluene on reaction mechanism was also investigated to account the interactions of solvent molecules with polar transition states at the same level of theory.

In many organisms, γ-glutamylmethylamide is a significant amino acid constituent. In this research, a novel method of γ-glutamylmethylamide synthesis is presented. The synthesis of γ-glutamylmethyl...

Ammonia and amines are important common trace atmospheric species that can enhance new particle formation (NPF) in the Earth’s atmosphere. However, the synergistic effect of these two bases involving nucleation is still lacking. We studied the most stable geometric structures and thermodynamics of quaternary (NH3)(CH3NH2)(H2SO4)m(H2O)n (m = 1–3, n = 0–4) clusters at the PW91PW91/6-311++G(3df,3pd) level of theory for the first time. We find that the proton transfer from H2SO4 molecule to CH3NH2 molecule is easier than to NH3 molecule in the free or hydrated H2SO4-base clusters, and thus leads to the stability. The energetically favorable formation of the (NH3)(CH3NH2)(H2SO4)m(H2O)n (n = 0–4) clusters, by hydration or attachment of base or substitution of ammonia by methylamine at 298.15 K, indicate that ammonia and methylamine together could enhance the stabilization of small binary clusters. At low RH and an ambient temperature of 298.15 K, the concentration of total hydrated (NH3)(CH3NH2)(H2SO4)2 cluster...

Formation of 15-membered azalactone by double reductive amination was analyzed using molecular mechanics and density functional theory calculations for simplified model compounds. As a result, the following aspects were clarified. When methylamine attacks a linear bis-aldehyde in the first step, there are possibilities that two regioisomers are formed. However, one of them exhibited remarkably stable energy level compared with the other. The stable isomer indicated a short distance between a methylamine moiety and an unreacted aldehyde. This short distance, about 2.3 Å, could be explained by hydrogen bonding, which implied relatively easy cyclization in the second step. Moreover, this cyclization process was supposed to be exothermic according to comparison of energy levels before and after cyclization.

The norbornenyl gluconamide (NBGA) monomer can be polymerized by a number of palladium catalysts to give water-soluble, vinyl addition poly(NBGA). Depending on the catalyst used, the reaction conditions, and the chain-transfer additives employed, high-molecular-weight polymers can be obtained. These polymers can be thermally cross-linked at ca. 190 °C or at ca. 150 °C when the difunctional glutaraldehyde is added. A photopatternable composition is formed by the addition of a water-soluble diazide when the poly(NBGA) molecular weight is sufficiently high. After image-wise exposure, negative-tone patterns are revealed by water development. A detailed analysis of NBGA monomer structures by high-resolution nuclear magnetic resonance techniques including pure shift is reported showing that two diastereomers of each endo- and exo-isomer are formed from the reaction of norbornene methylamine and δ-gluconolactone.

[1′-(Diphenylphosphino)ferrocenyl]methylamine (1) reacts with Ph2PH/(CH2O)x or [Ph2P(CH2OH)2]Cl to give mixtures of Ph2PfcCH2NHCH2PPh2 and Ph2PfcCH2N(CH2PPh2)2 in which the triphosphine dominates (fc = ferrocene-1,1′-diyl). To avoid unwanted two-fold phosphinomethylation, the amine group in 1 was alkylated. As expected, the reaction of the N-methyl analogue Ph2PfcCH2NHMe (5), obtained by reductive methylation of the aldehyde Ph2PfcCHO, with [Ph2P(CH2OH)2]Cl, only led to the diphosphine Ph2PfcCH2N(Me)CH2PPh2 (6). The diphosphine was structurally characterized and further reacted with [PdCl2(MeCN)2] and [PdCl(Me)(cod)] (cod = η2:η2-cycloocta-1,5-diene), affording the respective trans-chelate complexes [PdCl(X){Ph2PfcCH2N(Me)CH2PPh2-κ2P,P′}] (7a: X = Cl; 7b: X = Me), which were also structurally authenticated by X-ray diffraction analysis.

A one-pot, two-step, total synthesis of naturally occurring xenortides A, B, C and D, (Xens A-D) isolated from the bacterium Xenorhabdus nematophila, and an entire complementary set of stereoisomers, has been achieved. Compounds were synthesized utilizing an isocyanide-based Ugi 4-CR followed by facile N-Boc deprotection. The reaction sequence took advantage of the chiral pool of N-Boc protected amino acids (l-Leu/Val and d-Leu/Val) with aryl isocyanides, phenyl acetaldehyde and methylamine giving the desired Xens A-D (A and B >98% ee) and all subsequent stereoisomers in reasonable yields upon deprotection followed by separation of diastereomers. Also, detailed mechanistic insights for diastereoselectivity of (-)-Xen A, as a model in the Ugi 4-CR, has been described. Moreover, for the first time, this focused library was screened for cytotoxicity against a panel of epithelial cancer cell lines as well as normal cell lines with an MTT proliferation assay. The structure-activity relationship (SAR) study demonstrated that tryptamides Xen B and D were more active than phenylethylamides Xen A and C. Furthermore, (-)-Xen B (IC50 = 19-25 μM) and ent-(+)-Xen D (IC50 = 21-26 μM) gave the highest cytotoxicity and they were also found to be non-toxic toward normal cells. Importantly, the SAR results indicate that the stereochemistry at C8 and C11 in (-)-Xen B and ent-(+)-Xen D play a critical role in cytotoxic activity.

The imminent global energy crisis and current environmental issues have stimulated considerable research on high-performance catalysts for sustainable hydrogen energy generation. Two-dimensional layered MoS2 has recently drawn worldwide attention because of its excellent catalytic properties for the hydrogen evolution reaction (HER). In the present work, we prepared nitrogen (N)-rich 1T′ (distorted 1T) phase MoS2 layered nanostructures using different alkyl amines with 1–4 nitrogen atoms (methylamine, ethylenediamine, diethylenetriamine, and triethylenetetramine) as intercalants. The amine molecules intercalate at 10 atomic%, and simultaneously supply the N atoms that substitute the S atoms to produce the N-doped MoS2, whose composition is MoS2(1−x)Nx, where x = 0.1–0.26. MoS2 prepared with amines having more N atoms has enhanced catalytic HER performance: a Tafel slope of 36 mV dec−1 and 10 mA cm−2 at −160 mV (vs. RHE). First-principles calculations showed that the amine intercalation and N doping increase the density of states near the Fermi level in a narrow range and bring about an effective overlap of the dz2(Mo), pz(S), and pz(N) states. These factors in turn increase the carrier (electron) concentration and mobility for improved HER. The calculation also predicted that the most active site is S vacancies. The present work illustrates how the HER catalytic performance of 1T′ phase MoS2 can be effectively controlled by the amine molecules.

With biofuels market expanding, amines, as an important compound class in biofuels, are attracting increasing attention. The pyrolysis of n-propylamine (NPA) was studied in a flow tube using tunable synchrotron photoionization and molecular-beam mass spectrometry techniques. 28 and 30 species, including nitrogenous compounds and hydrocarbons, were identified and quantified at 30 and 760 Torr, respectively. 1,3-Cyclopentadiene, 1,4-pentadiene, 2-methyl-1,3-butadiene and benzene, were newly detected compared with previous studies of methylamine and ethylamine. HCN, NH3, N2 and methanimine were detected as the dominant nitrogenous products. Moreover, minor aliphatic and unsaturated amines were also identified, such as methylamine, ethylamine and acetaldimine. Ethylene achieved at the highest level among hydrocarbon products. With the pressure increasing, the onset temperature of NPA pyrolysis shifts towards low temperature region and NPA decomposes faster. A comprehensive detailed kinetic model involving 405 species and 2668 reactions was developed with reasonable predictions. According to rate-of-production analysis, H-abstractions, especially at Cα position of NPA, are the major consumption pathways of NPA. In addition, unimolecular reaction breaking Cα-Cβ bond is the important consumption channel of NPA at 30 Torr, while its positive effect is seriously weakened at 760 Torr. The H-abstraction at Cα (NPA+H CH3CH2CHNH2+H2) plays a leading role for NPA consumption at 760 Torr. The reactions, CH3+CH3=C2H5+H and CH3CHCHNH2+H CH2CHCHNH2+H2, tend to present inhibiting effects on NPA consumption at 30 and 760 Torr, respectively. These results could provide a theoretical basis for further combustion kinetic studies of biofuels and amine fuels.

The asymmetric reductive amination of ketones represents an elegant and convenient way to obtain chiral amines. Recently, several examples have been reported in which isolated imine reductases (IREDs) have been used for this type of reaction leading to promising results. In this work we focus on the applicability of whole cell biocatalysts (recombinant E. coli cells heterologously overexpressing an IRED) to simplify its preparation and to cut on catalyst production costs. Thirteen IREDs were screened towards six different ketones, using methylamine as amine donor. The targeted amines were formed with low to very high conversions and good to excellent stereoselectivity, depending on both, the ketone amine pair used for the reaction, as well as the applied IRED. It was further proven that a micro-aqueous reaction environment was applicable showing similar activity trends for the various reductive aminations but predominantly reduced conversions. A preparative scale experiment in a buffered environment was conducted leading to 93% conversion and 99% stereoselectivity of the product (1S,3R)-N,3-dimethylcyclohexylamine. As the whole cells intrinsic glucose dehydrogenase could be used for cofactor regeneration, no enzyme addition had to be applied, making this biocatalyst formulation particularly cost efficient.

Degradation via hydrolysis is among the main transformation pathways and particularly for N-methylcarbamates. Carbamate pesticide hydrolysis is known to proceed through alkaline catalysis, with reaction of the hydroxide ion with the carbonyl function or with abstraction of hydrogen in the α position with respect to the carbonyl. This reaction leads to the formation of methylamine and corresponding phenol. In this respect, the reaction kinetics of 4-bromo-3,5-dimethylphenyl N-methylcarbamate (BDMC) hydrolysis have been investigated in alkaline solution using a spectrophotometric technique and reversed phase liquid chromatography. The kinetic constants were determined following a proposed pseudo–first-order kinetic model. The positive activation entropy ΔS≠ = +35.73 J mol−1 K−1 and the absence of general base catalysis indicated an unimolecular elimination conjugate base (E1cB) hydrolytic mechanism involving the formation of methyl isocyanate. This result was confirmed by the fact that BDMC fits well into bronsted and Hammett lines, obtained for a series of substituted N-methylcarbamate whose decomposition in aqueous media was established to follow an E1cB mechanism.

A new continuous flow protocol for the diazotization of methylamine with 1,3-propanedinitrite in THF is reported. The synthesis of methyl esters was achieved in high yields from a variety of carboxylic acids in 20 min at 90 °C. Additionally, this protocol was extended to other aryl and alkyl amines, namely secondary amines, to produce various substituted esters in high yield using 2-MeTHF as a solvent. The reaction conditions were compatible with many functional groups, namely nitrogen-containing heterocycles, alkynes, alkenes, alcohols, and phenols. Mechanistic investigations reveal that the reaction appears to proceed through a transient diazonium species rather than a diazo intermediate.

Oxidation of guanine in the presence of lysine can lead to guanine-lysine cross-links. The ratio of the C4, C5 and C8 crosslinks depends on the manner of oxidation. Type II photosensitizers such as Rose Bengal and methylene blue can generate singlet oxygen, which leads to a different ratio of products than oxidation by type I photosensitizers or by one electron oxidants. Modeling reactions of singlet oxygen can be quite challenging. Reactions have been explored using CASSCF, NEVPT2, DFT, CCSD(T), and BD(T) calculations with SMD implicit solvation. The spin contamination in open-shell calculations were corrected by Yamaguchi's approximate spin projection method. The addition of singlet oxygen to guanine to form guanine endo- peroxide proceeds step-wise via a zwitterionic peroxyl intermediate. The subsequent barrier for ring closure is smaller than the initial barrier for singlet oxygen addition. Ring opening of the endoperoxide by protonation at C4-O is followed by loss of a proton from C8 and dehydration to produce 8-oxoGox . The addition of lysine (modelled by methylamine) or water across the C5=N7 double bond of 8-oxoGox is followed by acyl migration to form the final spiro products. The barrier for methylamine addition is significantly lower than for water addition and should be the dominant reaction channel. These results are in good agreement with the experimental results for the formation of guanine-lysine cross-links by oxidation by type II photosensitizers.

The conversion of Undaria pinnatifida residue to glycolic acid was carried out using methylamine as catalyst by hydrothermal method at relatively low temperature. GC–MS and HPLC were used to identify the composition of bio-oil and liquid products which provide the knowledge of the chemical reaction pathways of the hydrothermal liquefaction. The main liquid product was organic acid which contained glycolic acid, lactic acid, formic acid and acetic acid. And the major organic acid was glycolic acid with the highest yield of 46.52% or 33.98% of dry biomass. Methylamine promoted the dissolution of cellulose from Undaria pinnatifida residue, and significantly improved the yield of glycolic acid. The mechanism of HTL was investigated and the results show that the carbocation C3 was attacked by methylamine molecule which led to the high yield of glycolic acid. In addition, the recovery of methylamine was studied and the highest recovery rate reached 99.28%.

Atmospheric aerosols often contain a significant fraction of carbon-nitrogen functionality, which makes gas-phase aldehyde-amine chemistries an important source of nitrogen containing compounds in aerosols. Here we use high-level ab initio calculations to examine the key determinants of amine (ammonia, methylamine, and dimethylamine) addition onto three different aldehydes (acetaldehyde, glycolaldehyde, and 2-hydroperoxy acetaldehyde), with each reaction being catalyzed by a single water molecule. The model aldehydes reflect different degrees of oxygenation at a site adjacent to the carbonyl moiety, the α-site, and represent typical oxygenates that can arise from atmospheric oxidation especially under conditions where the concentration of NO is low. Our results show that the reaction barrier is influenced not only by the nature of the amine but also by the nature of the aldehyde. We find that, for a given amine, the reaction barrier decreases with increasing oxygenation of the aldehyde. This observed trend in barrier height can be explained through a distortion/interaction analysis, which reveals a gradual increase in internal hydrogen bonding interactions upon increased oxygenation, which, in turn, impacts the reaction barrier. Further, the calculations reveal that the reactions of methylamine and dimethylamine with the oxygenated aldehydes are barrierless under catalysis by a single water molecule. As a result, we expect these addition reactions to be energetically feasible under atmospheric conditions. The present findings have important implications for atmospheric chemistry as amine-aldehyde addition reactions can facilitate aerosol growth by providing low-energy neutral pathways for the formation of larger, less volatile compounds, from readily available smaller components.

Polydiacetylene/zinc oxide (PDA/ZnO) nanocomposites are demonstrated as colorimetric sensors for organic bases. Influence of stimuli structure on the color-transition behaviors is investigated. Addition of methylamine, ethylamine, butylamine and pentylamine into pure PDAs with different alkyl chain length induces blue-to-red transition at the same concentration. Interestingly, for PDA/ZnO, it shows an ability to differentiate these alkylamines. The detecting concentration and the ability to differentiate the alkylamines can be controlled by adjusting the alkyl chain length of PDA/ZnO. Moreover, PDA/ZnO-embedded paper is successfully fabricated and used to detect alkylamines in different media. Results extend the utilization of PDA-based materials in sensing technologies.

A new polymer surfactant derived from cis-1,4-cyclohexane bis(methylamine) and ethylenediamintetraacetic acid [2,2'-(1,12-bis(4-(aminomethyl)cyclohexyl)-3,10-dioxo-2,5,8,11-tetraazadodecane-5,8-diyl) diacetic acid ] was synthesized and characterized by FTIR and 1HNMR. A series of electrochemical measurements, including corrosion potential and corrosion current has been made on the surfactant for carbon steel samples in corrosive environment. Results showed that the surfactant can offer some degrees of protection in the corrosive environments. The corrosion study of this polymer outline that it have a good resistant to the corrosion of carbon steel in 0.1 M solution of HCl, which can be indicate to uses as anti-corrosion materials

Interactions of the three common atmospheric bases, dimethylamine ((CH3)2NH), methylamine (CH3NH2), ammonia (NH3), all considered to be efficient stabilizers of binary clusters in the Earth's atmosphere, with H2SO4, the key atmospheric precursor, and 14 common atmospheric organic acids (COAs) (formic, acetic, oxalic, malonic, succinic, glutaric acid, adipic, benzoic, phenylacetic, pyruvic, maleic acid, malic, tartaric and pinonic acids) have been studied using the density functional theory (DFT) and composite high-accuracy G3MP2 method. The thermodynamic stability of mixed (COA)(H2SO4), (COA)(B1), (COA)(B2) and (COA)(B3) dimers and (COA)(H2SO4)(B1), (COA)(H2SO4)(B2) and (COA)(H2SO4)(B3) trimers, where B1, B2 and B3 refer to (CH3)2NH, CH3NH2 and NH3, respectively, have been investigated and their impacts on the thermodynamic stability of clusters containing H2SO4 have been studied. Our investigation shows that interactions of H2SO4 with COA, (CH3)2NH, CH3NH2 and NH3 lead to the formation of more stable mixed dimers and trimers than (H2SO4)2 and (H2SO4)2(base), respectively, and emphasize the importance of common organic species for early stages of atmospheric nucleation. We also show that although amines are generally confirmed to be more active than NH3 as stabilizers of binary clusters, in some cases mixed trimers containing NH3 are more stable thermodynamically than those containing CH3NH2. This study indicates an important role of COA, which coexist and interact with that H2SO4 and common atmospheric bases in the Earth atmosphere, in formation of stable pre-nucleation clusters and suggests that the impacts of COA on new particle formation (NPF) should be studied in further details.

In atmospheric sulfuric-acid-driven particle formation, bases are able to stabilize the initial molecular clusters and thus enhance particle formation. The enhancing potential of a stabilizing base is affected by different factors, such as the basicity and abundance. Here we use weak (ammonia), medium strong (dimethylamine) and very strong (guanidine) bases as representative atmospheric base compounds, and we systematically investigate their ability to stabilize sulfuric acid clusters. Using quantum chemistry, we study proton transfer as well as intermolecular interactions and symmetry in clusters, of which the former is directly related to the base strength and the latter to the structural effects. Based on the theoretical cluster stabilities and cluster population kinetics modeling, we provide molecular-level mechanisms of cluster growth and show that in electrically neutral particle formation, guanidine can dominate formation events even at relatively low concentrations. However, when ions are involved, charge effects can also stabilize small clusters for weaker bases. In this case the atmospheric abundance of the bases becomes more important, and thus ammonia is likely to play a key role. The theoretical findings are validated by cluster distribution experiments, as well as comparisons to previously reported particle formation rates, showing a good agreement.