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The atomic precision of metal nanoclusters and variability of surface ligands pave the way for their rational design and functionalization, whereas the property strengthening in multiple ways has been long challenging. Herein, improved amphiphilicity, chirality, thermostability, and strong CPL (circularly polarized luminescence) properties have been accomplished by facile ligand exchange of [Au23(CHT)16]− with HCapt (HCHT and HCapt denote cyclohexanethiol and captopril). In addition, the obtained chiral [Au23(SR)16]− (short for [Au23(CHT)16‐x(Capt)x]−) clusters show specific binding affinity to remote‐diamines (such as arginine and single/double strand DNA), originating from the hydrogen bonding and Van der Waals interaction among the surface Capt ligands and the di‐amine groups. [ABSTRACT FROM AUTHOR]

Herein we report the crystal structures of two benzodiazepines obtained by reacting N,N′‐(4,5‐diamino‐1,2‐phenylene)bis(4‐methylbenzenesulfonamide) (1) or 4,5‐(4‐methylbenzenesulfonamido)benzene‐1,2‐diaminium dichloride (1·2HCl) with acetone, giving 2,2,4‐trimethyl‐8,9‐bis(4‐methylbenzenesulfonamido)‐2,3‐dihydro‐5H‐1,5‐benzodiazepine, C26H30N4O4S2 (2), and 2,2,4‐trimethyl‐8,9‐bis(4‐methylbenzenesulfonamido)‐2,3‐dihydro‐5H‐1,5‐benzodiazepin‐1‐ium chloride 0.3‐hydrate, C26H31N4O4S2+·Cl−·0.3H2O (3). Compounds 2 and 3 were first obtained in attempts to recrystallize 1 and 1·2HCl using acetone as solvent. This solvent reacted with the vicinal diamines present in the molecular structures, forming a 5H‐1,5‐benzodiazepine ring. In the crystal structure of 2, the seven‐membered ring of benzodiazepine adopts a boat‐like conformation, while upon protonation, observed in the crystal structure of 3, it adopts an envelope‐like conformation. In both crystalline compounds, the tosylamide N atoms are not in resonance with the arene ring, mainly due to hydrogen bonds and steric hindrance caused by the large vicinal groups in the aromatic ring. At a supramolecular level, the crystal structure is maintained by a combination of hydrogen bonds and hydrophobic interactions. In 2, amine‐to‐tosyl N—H...O and amide‐to‐imine N—H...N hydrogen bonds can be observed. In contrast, in 3, the chloride counter‐ion and water molecule result in most of the hydrogen bonds being of the amide‐to‐chloride and ammonium‐to‐chloride N—H...Cl types, while the amine interacts with the tosyl group, as seen in 2. In conclusion, we report the synthesis of 1, 1·2HCl and 2, as well as their chemical characterization. For 2, two synthetic methods are described, i.e. solvent‐mediated crystallization and synthesis via a more efficient and cleaner route as a polycrystalline material. Salt 3 was only obtained as presented, with only a few crystals being formed. [ABSTRACT FROM AUTHOR]

ObjectivesThe absorption and regeneration properties of different formulations of methyldiethanolamine (MDEA) mixed with different diamines were studied.MethodsIn the simulated flue gas environment with 12% CO2 and 88% N2, MDEA was used as the main agent, while ethylenediamine (EDA), 1,3-diaminopropane (DAP), N-methyl-1,3-propanediamine (MAPA), aminoethylethano-lamine (AEEA), N,N-dimethylethylenediamine (DMEDA) and 3-dimethylaminopropylamine (DMPDA) were added as activators, respectively. Under a total amine concentration of 40%, the chemical absorbent was configured with mass ratios of main agent to activator of 1∶1, 2∶1 and 3∶1, respectively. The absorption rate, regeneration rate and circulation capacity of different absorbers were determined by comparing bubble absorption and oil bath regeneration experiments.ResultsMDEA-EDA system has the best absorption property when the mass ratio of MDEA to EDA is 1∶1. The MDEA-DMEDA system has the best regeneration property when the mass ratio of MDEA to DMEDA is 2∶1, with a circulation capacity reaching 1.7 mol/kg. The overall properties of MDEA-AEEA system are optimized when the mass ratio of MDEA to AEEA is 1∶1, with a cycle capacity reaching 1.49 mol/kg.ConclusionsThe research results can provide a theoretical basis for the formulation optimization of mixed amine solutions in industry.

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The possibility of spontaneous reduction of benzofuroxans to benzofurazans in course of time due to reactions with diamines was shown for the first time. A possible mechanism of the reaction of 4,6-dichloro-5-nitrobenzofuroxan with diamines and related amines was analyzed by the quantum-chemical method. The results of research fully confirm the obtained experimental data and explain the impossibility of the subsequent reduction of amino-containing benzofuroxans due to a high activation barrier. [ABSTRACT FROM AUTHOR]

Novel organometallic complexes Mn(benzene-1,2-diamine)(CO)3Br, Mn-1, Mn(3-methylbenzene-1,2-diamine)(CO)3Br, Mn-2, and Re(benzene-1,2-diamine)(CO)3Cl, Re-1, have been synthesized and characterized by IR, UV/Vis, 1H-NMR, EA and HRMS. The structures of Mn-2 and Re-1 were confirmed by X-ray crystallography. The three novel compounds were studied for their electrocatalytic reduction of carbon dioxide to carbon monoxide using cyclic voltammetry in acetonitrile solutions. Controlled potential electrolysis was used to obtain information on faradaic yield, with product formation being confirmed by GC. Using earth-abundant manganese, compounds Mn-1 and Mn-2 display turnover frequencies of 108 s−1 and 82 s−1, respectively, amid selective production of carbon monoxide (faradaic yields ~85%), with minimal co-production of dihydrogen (<2%), and low overpotential of 0.18 V. The rhenium congener, Re-1, displays no activity as an electrocatalyst for carbon dioxide reduction under identical conditions. [ABSTRACT FROM AUTHOR]

Here, two different novel sulfonated polyimides were produced using different monomer ratios. With 2 different molecules of diamine, 3,3′,4,4′-biphenyl tetracarboxylic dianhydride and perylene-3, 4, 9, 10-tetracarboxylic dianhydride in an inert atmosphere at two-stage high temperature and the presence of sulfonic acid, sulfonated polyimides were obtained by imidization. For sulfonated polyimides, proton nuclear magnetic resonance, Fourier transform infrared, solubility tests, the affinity of polymers to solvents, ultraviolet–visible spectroscopy and thermogravimetric analysis/differential thermal analysis characterization were performed. Quantum chemical calculations of synthesized sulfonated polyimides, density functional theory and analysis of atoms in molecules theoretical calculations are presented to learn about various energy properties and to see proton transfer scripts. The thermogravimetric analysis/differential thermal analysis curve showed a second degradation stage at a temperature higher than 400 °C. [ABSTRACT FROM AUTHOR]

By reactions of both catalyzed and non‐catalyzed pathway, we attempt to show that the synthetic route of non‐isocyanate polyurethanes (NIPU) is developed quite recently. The advancement of sustainable, bio‐renewable, impermeable and moisture‐insensitive NIPU has started to contribute its role in academia and industry. In case of NIPU formulation, polycondensation of dicarbonate with diamine precursors as well as waste‐free polyaddition of multifunctional cyclic carbonates with diamines via ring‐opening polymerization. Obviously, since the hydroxyl groups (both primary and secondary hydroxyl group) arisen in NIPU is employed to reveal fairly different attributes compared to trivial polyurethanes (PU). The advantage of NIPU comprises of the role of carbon dioxide and renewable feedstock, while various cyclic carbonates obtained to react with diamine substrates to incorporate desired physicochemical and mechanical properties. Indeed, NIPU are noted to be non‐toxic, biodegradable and exhibit remarkable properties. In this review, we account the imperative strategies employed in developing essential sustainable NIPU have been discussed in detail. [ABSTRACT FROM AUTHOR]

Abstract Background Infections by gastrointestinal nematodes cause significant economic losses and disease in both humans and animals worldwide. The discovery of novel anthelmintic drugs is crucial for maintaining control of these parasitic infections. Methods For this purpose, the aim of the present study was to evaluate the potential anthelmintic activity of three series of compounds against the gastrointestinal nematodes Trichuris muris and Heligmosomoides polygyrus in vitro. The compounds tested were derivatives of benzimidazole, lipidic aminoalcohols and diamines. A primary screening was performed to select those compounds with an ability to inhibit T. muris L1 motility by > 90% at a single concentration of 100 µM; then, their respective IC50 values were calculated. Those compounds with IC50 < 10 µM were also tested against the adult stage of T. muris and H. polygyrus at a single concentration of 10 µM. Results Of the 41 initial compounds screened, only compounds AO14, BZ6 and BZ12 had IC50 values < 10 µM on T. muris L1 assay, showing IC50 values of 3.30, 8.89 and 4.17 µM, respectively. However, only two of them displayed activity against the adult stage of the parasites: BZ12 killed 81% of adults of T. muris (IC50 of 8.1 µM) and 53% of H. polygyrus while BZ6 killed 100% of H. polygyrus adults (IC50 of 5.3 µM) but only 17% of T. muris. Conclusions BZ6 and BZ12 could be considered as a starting point for the synthesis of further structurally related compounds. Graphical Abstract

Impaired mitophagy is a primary pathogenic event underlying diverse aging-associated diseases such as Alzheimer and Parkinson diseases and sarcopenia. Therefore, augmentation of mitophagy, the process by which defective mitochondria are removed, then replaced by new ones, is an emerging strategy for preventing the evolvement of multiple morbidities in the elderly population. Based on the scaffold of spermidine (Spd), a known mitophagy-promoting agent, we designed and tested a family of structurally related compounds. A prototypic member, 1,8-diaminooctane (VL-004), exceeds Spd in its ability to induce mitophagy and protect against oxidative stress. VL-004 activity is mediated by canonical aging genes and promotes lifespan and healthspan in C. elegans. Moreover, it enhances mitophagy and protects against oxidative injury in rodent and human cells. Initial structural characterization suggests simple rules for the design of compounds with improved bioactivity, opening the way for a new generation of agents with a potential to promote healthy aging. [ABSTRACT FROM AUTHOR]

New various monomers with di amine functional groups have been synthesized, containing di azomethine or di seven-membered heterocyclic rings in the backbone. A condensation reaction of benzidine with 4-amino benzaldehyde with some drops of glacial acetic acid in ethanol absolute prepared bi-functional amino groups monomer with azomethine core P1(4-[(1E)-[4[4-(E)-(4- aminophenyl)methylidene]amino]phenyl}phenylimino methyl aniline). The next step was the Cycloaddition reaction of P1 with succinic, malic, and phthalic anhydrides used to obtain aromatic heterocyclic monomers with oxazepane and oxazepine rings containing lactone and lactam groups. All the synthesized monomers were characterized spectrally with many techniques (FT.IR,1 H1.NMR, C13-NMR) that were used to investigate the functional groups in the structure of monomers. Monitoring the progress and completion of the reaction was performed using thin-layer chromatography (TLC). Physical characterizations, including detecting the melting point, purity, colour, retardation factor, molecular formula, and molecular weight, the polarized optical microscope (POM) used for Image-based microscopic interpretation of prepared compounds. All the prepared monomers are considered effective antioxidant agents as they give free radicals scavenging over 60%, reaching 80 %; this activity makes them useful in large numbers of industries as they can scavenge the free radicals that the industrial product may be exposed, which increases its shelf life and enhance its effectiveness. [ABSTRACT FROM AUTHOR]

A new series of 1H‐pyrrolo[1,2‐a]imidazol‐6‐yl)acetamides and pyrrolo[1,2‐a]pyrimidin‐7‐yl)acetamides were synthesized by the ultrasound‐assisted tandem pseudo‐four‐component reaction (pseudo‐4CR). The present study reports the use of phenyglyoxal derivatives, malononitrile, 1,1‐bis(methylsulfanyl)‐2‐nitroethene, and diamines in EtOH as a green solvent to reach a product with excellent yields (85–95 %). Their structures were characterized by spectroscopic data (IR, MS, 1H, and 13C NMR) and verified by X‐ray analysis. The results revealed the influence of the electron‐withdrawing or electron‐donating substituent on the arylglyoxal ring and carbon chain length of the diamine on the formation of final product (pyrrole or pyridine ring). 1,2‐Diamines with arylglyoxal having electron‐withdrawing and electron‐donating substituent trigger the formation of the pyrrole and pyridine ring, respectively. However, 1,3‐diamines lead to only the formation of the pyrrole ring. This efficient and green protocol has remarkable advantages, such as abundant starting materials, simple operation, clean reaction profile, easy purification without traditional methods (i. e. column chromatography and crystallization), excellent tolerance to various substituents, and relatively short reaction time. [ABSTRACT FROM AUTHOR]

• Crystal structure of 4,4′-(benzo[c][1,2,5]thiadiazole-4,7-diyl)dianiline is reported. • The emission color of the dye was highly dependent on the solvent polarity. • The dye is electrofluorochromic with photoemission modulation with a potential. • The dye is electrochromic changing yellow to blue with a potential. Two independent molecules of the crystal structure of the title compound C 18 H 14 N 4 S were found to occupy the asymmetric unit of the space group. The flanking 4-anilines were not coplanar with the central benzothiadiazole. In the crystal, two unique types of hydrogen bonds were found: i) one set between two NH 2 of two molecules in the asymmetric unit and ii) another set between hydrogen atoms of the second aniline NH 2 and the nitrogen atom of benzothiadiazole. The two-dimensional fingerprint plots along with the Hirshfeld surface confirmed the most important contributions for the crystal packing were C···H, H···H and N···H interactions. The compound was also solvatochromic with both its emission wavelength and quantum yield contingent on the solvent polarity. The fluorophore had a reversible oxidation. This was used to induce both a reversible color change from yellow to blue and emission off/on with an applied potential. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] Biphasic solvents can decrease the regeneration energy of CO 2 capture. As an intramolecular hybrid diamine, 3-Dimethylaminopropylamine (DMAPA) had a primary amino group and a tertiary amino group, which could absorb CO 2 by combining zwitterion and base-catalyzed hydration mechanism. The derived DMAPA/ n -PeOH/H 2 O biphasic absorbent possessed high CO 2 absorption capacity (1.46 mol/mol) and large CO 2 -rich phase loading (6.27 mol/L), which were superior to existing mixed amine systems. At 393.15 K, this system had a large desorption amount of 4.91 mol/L and a fast desorption rate (6.68 E-3 mol/L·s), which were 2.84 and 3.73 times of 30 wt% MEA. The associated total regeneration energy was reduced to 1.36 GJ/t CO 2 , only 34.1 % of MEA absorbent. The reaction mechanism and origin of phase separation were revealed by NMR analysis and quantum chemistry calculations. In addition, low viscosity and corrosiveness were revealed and conducive for industrial application. [ABSTRACT FROM AUTHOR]

Novel organometallic complexes Mn(benzene-1,2-diamine)(CO)3Br, Mn-1, Mn(3-methylbenzene-1,2-diamine)(CO)3Br, Mn-2, and Re(benzene-1,2-diamine)(CO)3Cl, Re-1, have been synthesized and characterized by IR, UV/Vis, 1H-NMR, EA and HRMS. The structures of Mn-2 and Re-1 were confirmed by X-ray crystallography. The three novel compounds were studied for their electrocatalytic reduction of carbon dioxide to carbon monoxide using cyclic voltammetry in acetonitrile solutions. Controlled potential electrolysis was used to obtain information on faradaic yield, with product formation being confirmed by GC. Using earth-abundant manganese, compounds Mn-1 and Mn-2 display turnover frequencies of 108 s−1 and 82 s−1, respectively, amid selective production of carbon monoxide (faradaic yields ~85%), with minimal co-production of dihydrogen (Re-1, displays no activity as an electrocatalyst for carbon dioxide reduction under identical conditions.

A facile synthesis of ketones was developed based on the diamine‐promoted deacylation of 2‐alkyl‐1,3‐diketones. More specifically, 2‐alkyl‐1‐arylbutane‐1,3‐diones were efficiently deacylated in the presence of 2,2‐dimethylpropane‐1,3‐diamines to afford the corresponding aryl ketones with a high regioselectivity. Notably, this regioselectivity was different from that observed under the conventional retro‐Claisen conditions. [ABSTRACT FROM AUTHOR]

Structures of volatile mixed-ligand complexes of magnesium with N,N,N′,N′-tetramethylethylenediamine (tmeda) and fluorinated β-diketonate ligands L = CF3C(O)CHC(O)R– (R = t-Bu (ptac) and Ph (btfac)) are determined. Complex [Mg(tmeda)(btfac)2] is obtained for the first time and is characterized by elemental analysis and IR spectrometry. Both [Mg(tmeda)(L)2] compounds are molecular complexes, and the symmetry of their crystals is increased due to the presence of an aromatic substituent: space groups Pccn (L = btfac) and P21/n (L = ptac). The magnesium atom occurs in a distorted octahedral environment of three chelate ligands. The bond lengths and chelate angles in both complexes are similar: d(Mg–N) = 2.226(2)-2.245(1) Å, d(Mg–O) = 2.030(2)-2.043(2) Å, θ(N–Mg–N) = 80.97(7)-81.68(10)°, θ(O–Mg–O) = 85.61(9)-85.75(7)°. The Hirshfeld surfaces (CrystalExplorer, Tonto) show a presence of weak intermolecular contacts C–HPh...F in the [Mg(tmeda)(btfac)2] packing (4 contacts per molecule). The qualitative order of volatility decrease for the complexes and their hexafluoroacetylacetonate analogue [Mg(tmeda)(hfac)2] (TGA and vacuum sublimation data) corresponds to the estimated energy increase of [Mg(tmeda)(L)2] crystal lattices (CrystalExplorer, B3LYP/6-31G(d,p)): L = hfac ~ ptac >> btfac. [ABSTRACT FROM AUTHOR]

Tetradentate acyclic compartmental Schiff base ligand with N2O2 compartment afford suitable coordination environment for large variety of metal ions. This type of ligands can easily be synthesized by [2+1] condensation of a carbonyl compounds with a diamine. Several metal complexes have been reported from the single- and double-compartment acyclic Schiff base ligands which are the [2+1] condensation products of salicylaldehyde, 2-hydroxyacetophenone, 3-methoxysalicylaldehyde, 3-ethoxysalicylaldehyde and a diamine; The diamine counterpart in these ligands are ethylenediamine, 1,3-diaminopropane, 1,4-diaminobutane, 1-methylethylenediamine, 2,2-dimethyl, 1,3-diaminopropane, o-phenylenediamine, trans-1,2-diaminocyclohexane, etc. Several review article has been published previously on compartmental Schiff base ligand compounds. This review article focused only the type and structures of Cu(II)/Ni(II)-second metal (s-, p-, d10-, 3d-, 4f-block metal) homo-/hetero- nuclear coordination comppounds derived from single compartmentl salicyaldehyde-diamine and acetophenone-diamine ligand systems. [ABSTRACT FROM AUTHOR]

Background: Infections by gastrointestinal nematodes cause significant economic losses and disease in both humans and animals worldwide. The discovery of novel anthelmintic drugs is crucial for maintaining control of these parasitic infections. Methods: For this purpose, the aim of the present study was to evaluate the potential anthelmintic activity of three series of compounds against the gastrointestinal nematodes Trichuris muris and Heligmosomoides polygyrus in vitro. The compounds tested were derivatives of benzimidazole, lipidic aminoalcohols and diamines. A primary screening was performed to select those compounds with an ability to inhibit T. muris L1 motility by > 90% at a single concentration of 100 µM; then, their respective IC50 values were calculated. Those compounds with IC50 < 10 µM were also tested against the adult stage of T. muris and H. polygyrus at a single concentration of 10 µM. Results: Of the 41 initial compounds screened, only compounds AO14, BZ6 and BZ12 had IC50 values < 10 µM on T. muris L1 assay, showing IC50 values of 3.30, 8.89 and 4.17 µM, respectively. However, only two of them displayed activity against the adult stage of the parasites: BZ12 killed 81% of adults of T. muris (IC50 of 8.1 µM) and 53% of H. polygyrus while BZ6 killed 100% of H. polygyrus adults (IC50 of 5.3 µM) but only 17% of T. muris. Conclusions: BZ6 and BZ12 could be considered as a starting point for the synthesis of further structurally related compounds. [ABSTRACT FROM AUTHOR]

We report a short synthetic route for synthesizing 2,3-substituted piperazine acetic acid esters. Optically pure amino acids were efficiently converted into 1,2-diamines that could be utilized to deliver the title 2,3-substituted piperazines in five steps with a high enantiomeric purity. The novel route facilitated, for the first time, the synthesis of 3-phenyl substituted-2-piperazine acetic acid esters that were difficult to achieve using other methods; however, in this case, the products underwent racemization. [ABSTRACT FROM AUTHOR]

A novel sulfone ether amide diamine was prepared through a two-step synthetic route. At first, 3,3′-((sulfonyl bis(1,4-phenylene))bis(oxy))dianiline was prepared from nucleophilic aromatic substitution reaction of 3-aminophenol with 4,4′-dichlorodiphenyl sulfone in the presence of K2CO3. In the second step, the reaction of this compound with isophthaloyl chloride resulted in the preparation of a unique aromatic diamine containing amide, ether, and sulfone groups. Then three different kinds of poly(sulfone-ether-amide-imide)s were prepared via polycondensation reaction of the synthesized diamine with different dianhydrides including pyromellitic dianhydride, benzophenonetetracarboxylic dianhydride, and hexafluoroisopropylidene diphthalic anhydride. The structures of synthesized precursors, monomer, and prepared polymers were characterized using elemental analysis, 1H-NMR and FT-IR spectroscopy methods. Inherent viscosity, molecular weight, thermal behavior and stability, flame retardancy, and solubility of polymers were studied. As the polymers showed high thermal stability and also improved solubility, they can be used as heat and fire resistant materials. [ABSTRACT FROM AUTHOR]

A highly efficient and catalyst-free protocol is reported for the synthesis of quinoxalines via the classical cyclocondensation reaction between aryldiamines and dicarbonyl compounds. Remarkably simple and green reaction conditions employing methanol as solvent afforded medium to excellent yield of quinoxalines after only one-minute reaction time at ambient temperature. The conditions allow at least 10 gram scale synthesis of quinoxalines and should be a preferred starting point for optimization and method of choice for applications in the synthetic community.

Main observation and conclusion: Three diamines (1,8‐diaminooctane/p‐phenylenediamine/biphenylenediamine) with different alkyl groups were used to synthesize the functionalized graphene networks. Pd as the common metal catalyst was used to explore the effects of alkyl types of diamines on anti‐stacking, metal anchoring ability of functional graphene and hence the catalytic performance. The results were discussed by characterization of the material and its catalytic properties. All catalysts showed excellent catalytic performance on the Suzuki cross‐coupling reaction with a high yield of up to 100%. The p‐phenylenediamine and biphenylenediamine functionalized graphene with larger specific surface area was beneficial to improve the stability of the graphene catalyst and maintain good catalytic activity after 5 cycles. The Pd nanoparticles in 1,8‐octanediamine materials have smaller size and a smaller loading with the same or even better catalytic performance than p‐phenylenediamine, biphenylenediamine materials, due to the stronger electron donating ability of N of octanediamine than that of p‐phenylenediamine. [ABSTRACT FROM AUTHOR]

The industrial application of emerging water‐lean solvents to CO2 capture from flue gas is challenged by their high viscosity. In this work, we report a novel water‐lean CO2 solvent which possesses lower viscosity and higher CO2 cyclic capacity than other water‐lean solvents reported in the literature. The new solvent consists of N, N‐dimethyl‐1, 2‐ethanediamine (DMEDA), physical cosolvent N‐methyl‐2‐pyrrolidone (NMP) and up to 15% water (named ENH). We evaluated the effect of the solvent composition on the viscosity, CO2 cyclic capacity and regeneration energy of ENH and compared it with the reference monoethanolamine (MEA) based solvents. It was found that ENH containing 5% H2O (ENH‐5%H2O) with a CO2 loading of 0.767 mol CO2·mol amine–1 had a viscosity of 7.603 mPa·S at 40 ˚C, which was comparable with that of traditional blended amines. Excellent cyclic capacity performance was also observed, with ENH‐5% H2O showing a 140% improvement compared to aqueous MEA. Regeneration energy of ENH‐5% H2O was estimated to be 2.418 GJ·tCO2–1 which is 36% lower than the 30 wt. % aqueous MEA solvent. © 2021 Society of Chemical Industry and John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The recovery of thorium from acidic chloride medium with amine grafted cellulose resins was studied. Mesoporous polymers were modified with ethylenediamine (R1) and diethylenetriamine (R2) after grafting with glycidyl methacrylate. The sorbents obtained were characterized by Fourier transform IR spectroscopy, thermogravimetric analysis, scanning electron microscopy, and surface area measurements. Modified cellulose resins showed high capacity with relative fast kinetics in batch sorption of Th(IV) ions from chloride aqueous solutions. The maximum uptake capacity for Th(IV) ions on R1 and R2 was found to be 80 and 94.6 mg g–1 at pH 3.0 at 25°C within 45 min. The adsorption reaction followed the pseudo-second-order model. The data were fitted well by Langmuir isotherm. The mean adsorption energy calculated using DR isotherm showed that the adsorption followed the chemisorption mechanism. The process was exothermic. The performance of the sorbents in the recovery of Th(IV) ions from a standard rock sample and a granite sample from Gattar area, Egypt, was studied. Desorption was performed using different acids. The maximum Th(IV) desorption, 95 ± 2.8%, was reached with 1 M HNO3. [ABSTRACT FROM AUTHOR]

Polyimide aerogels (PAs) using different monomers were prepared by cross-linking with a low-cost aminosilane, bis(trimethoxysilylpropyl) amine. The influence of diamine rigidity and dianhydride rigidity on the microstructure, thermal and mechanical properties of PAs were investigated independently. It was found that Young's modulus and yield strength of the PAs increase with the increase of rigidity of diamine or dianhydride. PA prepared with the most rigid dianhydride (pyromellitic dianhydride, PMDA) and diamine (4,4′-oxydianiline, ODA) shows the highest Young's modulus of 45.7 MPa, while that prepared with the most rigid diamine (p-phenylenediamine, PPDA) and dianhydride (biphenyl-3,3′,4,4′-tetracarboxylic dianhydride, BPDA) exhibits the highest yield strength of 2.9 MPa. PAs prepared with more flexible diamines tend to form more disordered microstructure with larger pores and broader pore size distribution. Meanwhile, the thermal conductivity of PAs shows a decreasing tendency with the decrease of diamine rigidity. The lowest thermal conductivity of 0.038 W/(m·K) comes from the sample synthesized using ODA and BPDA. Besides, the initial thermal decomposition temperature depends mainly on the diamine, which illustrates that diamine rigidity has a greater effect on thermal stability than dianhydride rigidity. By contrast, no obvious correlation between the dianhydride rigidity and properties of PAs was observed. The obtained PAs exhibit good application potential for aerospace applications and their properties can be tailored by adjusting the monomer rigidity. [ABSTRACT FROM AUTHOR]

A new pair of 2,2ʹ-diamino-1,1ʹ-binaphthyl linked porphyrin dimers, (R)-/(S)-H, were synthesized to study their supramolecular interactions with a pair of chiral diamines ((R)-/(S)-PPDA) by using UV-Vis absorption, fluorescence and NMR titrations. The spectroscopic titrations indicated that sandwich-type 1:1 complexes were formed at low guest concentration and then transformed to 1:2 open complexes at high guest concentration. The supramolecular interactions afforded sensitive circular dichroism responses, and the CD signs of the 1:1 complexes are decided by the stereostructure of chiral diamine guests. Moreover, due to the shortened linking units, (R)-/(S)-H show more sensitive and predicable CD response than the previously reported hosts (R)-/(S)-H1 and this can be reasonably explained by DFT molecular modeling. The present results suggest (R)-/(S)-H are promising for chiral optical sensing.

We report a short synthetic route for synthesizing 2,3-substituted piperazine acetic acid esters. Optically pure amino acids were efficiently converted into 1,2-diamines that could be utilized to deliver the title 2,3-substituted piperazines in five steps with a high enantiomeric purity. The novel route facilitated, for the first time, the synthesis of 3-phenyl substituted-2-piperazine acetic acid esters that were difficult to achieve using other methods; however, in this case, the products underwent racemization.

In this study, a series of new N-aryl-2-(2-hydroxyphenylamino)ethylenediamine derivatives has been designed, synthesized and evaluated for antifungal activity against six selected species of phytopathogenic fungi. Among the products, the most potent compound have demonstrated 97.7% inhibitory activity against S. sclerotiorum at the concentration of 50 μg/mL, which is higher than that of the positive control chlorothalonil. [ABSTRACT FROM AUTHOR]

Present work analyses the behavior of aqueous solutions of N,N‐dimethylethylenediamine as chemical solvent for carbon dioxide separation by gas–liquid absorption. The interest of this molecule is centered on the presence of different types of amino centers that confer it the capability to act as a solvent based on amines blend. For this reason, a comparison between diamine and amines blend solvent has been carried out in order to understand the differences between these solvents using absorption and nuclear magnetic resonance studies. This experimental work analyses the influence of amine type, concentration, and ratio between different amines. Also, the effect of gas flow rate used in the bubble column reactor upon the absorption kinetics has been analyzed. [ABSTRACT FROM AUTHOR]

The mononuclear Ni(II) complexes [Ni(en)2(H2O)2](MAA)2 (1) and [Ni(pn)2(MAA)2] (2), where MAA, en and pn are methacrylate, ethylendiamine and 1,3-propylendiamine, respectively, have been synthesized and characterized by elemental analysis, FT-IR and UV–Vis spectroskopy. Structures of the complexes have been determined by single-crystal X-ray diffraction analyses. In the nickel(II) complexes 1 and 2 nickel(II) ion is six-coordinate and has a distorted octahedral geometry. Ni(II) is bonded to four nitrogen atoms of the two diamines and additionally to two oxygen atoms of aqua ligand in 1, and two oxygen atoms of methacrylate ligands in 2. The theoretical geometries of the studied compounds have been calculated by means of density functional theory (DFT) at the B3LYP/6-311+G(d,p)/LanL2DZ level and considering effective core potential (ECP). The comparison of the results indicates that the employed DFT method yields good agreement with experimental data.

An efficient green route for monoacylation of aromatic diamines, namely o-phenylenediamine and p-phenylenediamine and aliphatic diamines ethylenediamine and piperazine using N-acylbenzotriazoles (NABs) in n-butanol was developed. The new protocol does not require prior selective protection of the diamine and comprises simple conditions, short reaction times, an easy work up as well as high isolated yields (69–94%). Moreover, the method described herein enable stepwise acylation of aliphatic diamines such as ethylenediamine and piperazine with two different N-acylbenzotriazoles affording unsymmetrical substituted diamines that can be used for construction of pharmaceutically important targets such as drugs, foldamers, and drug conjugates. [ABSTRACT FROM AUTHOR]

Microbial production of chemicals and materials from renewable carbon sources is becoming increasingly important to help establish sustainable chemical industry. In this paper, we review current status of metabolic engineering for the bio-based production of linear and saturated dicarboxylic acids and diamines, important platform chemicals used in various industrial applications, especially as monomers for polymer synthesis. Strategies for the bio-based production of various dicarboxylic acids having different carbon numbers including malonic acid (C3), succinic acid (C4), glutaric acid (C5), adipic acid (C6), pimelic acid (C7), suberic acid (C8), azelaic acid (C9), sebacic acid (C10), undecanedioic acid (C11), dodecanedioic acid (C12), brassylic acid (C13), tetradecanedioic acid (C14), and pentadecanedioic acid (C15) are reviewed. Also, strategies for the bio-based production of diamines of different carbon numbers including 1,3-diaminopropane (C3), putrescine (1,4-diaminobutane; C4), cadaverine (1,5-diaminopentane; C5), 1,6-diaminohexane (C6), 1,8-diaminoctane (C8), 1,10-diaminodecane (C10), 1,12-diaminododecane (C12), and 1,14-diaminotetradecane (C14) are revisited. Finally, future challenges are discussed towards more efficient production and commercialization of bio-based dicarboxylic acids and diamines. Image 1 • Bio-based production of chemicals is becoming increasingly important. • Several dicarboxylic acids and diamines are produced by engineered microorganisms. • Strategies for the production of C3 C15 dicarboxylic acids are showcased. • Strategies for the production of C3 C14 diamines are showcased. [ABSTRACT FROM AUTHOR]

Amine-based absorption processes are widely used in natural gas processing, but recently they have been considered for CO2 capture from flue gas emitted from thermal power plants. The main issue of amine used in the CO2 capture process is the high cost of solvent regeneration. So, this issue can be solved by using efficient amine absorbent. The amine type absorbents employed in the experimentation were an aqueous blend of 2-(Diethylamino)ethanol (DEEA) with different types of diamine activators such as piperazine (PZ), 2-(2-aminoethylamino)ethanol (AEEA), hexamethylenediamine (HMDA), ethylenediamine (EDA), and 3-(Dimethylamino)-1-propylamine (DMAPA). An absorption experiment was performed to evaluate the CO2 absorption performance in terms of CO2 loading, absorption capacity, and absorption rate. The experiment was performed to assess the CO2 desorption performance in terms of desorption capacity, desorption rate, cyclic capacity, and regeneration efficiency. From the results of absorption-desorption and comparison with benchmark amine absorbent MEA, the aqueous blend of DEEA and HMDA indicated the best performance for CO2 capture applications among all the tested amine blends. [ABSTRACT FROM AUTHOR]

Para-phenylenediamine (PPD), also called paraaminobenzene, is an aromatic amine derived from aniline. PPD intoxication is little known in Europe, but widespread in humans in Asia, Middle East and North Africa, including Tunisia, where this substance is widely used by women for a cosmetic purpose. This chemical element is referred to as "Dabgha Roumia" or "black stone". The knowledge of toxicity of "Dabgha Roumia" led to its use it in poisoned baits in malicious intoxications against dogs and cats. Thus, paraphenylenediamine (PPD) poisoning in domestic carnivores is emerging in Tunisia, since 2017. No description of PPD intoxication regarding domestic carnivores is available in literature yet, hence the importance of describing its clinical specificities; toxicological analysis is obviously of great interest in confirming the clinical diagnosis, to develop toxicological diagnostic tools and implement a therapeutic protocol. The severity of the PPD intoxication involves the animal's vital prognosis, which imposes certain knowledge of its clinical manifestations by veterinary practitioners, for an efficient therapeutic management. In this paper, after an extensive literature review, we describe the clinical features of PPD poisoning in domestic carnivores, the poisoning being analytically confirmed by 2 qualitative methods and high performance liquid chromatography (HPLC). In addition, we are implementing a therapeutic protocol based on emetic, corticosteroids and vitamin C. [ABSTRACT FROM AUTHOR]

The cage of 2,5-diazabicyclo[2.2.1]heptane is frequently employed in synthetic chemistry as a rigid bicyclic counterpart of the piperazine ring. The 2,5-diazabicyclo[2.2.1]heptane scaffold is incorporated into a variety of compounds having pharmacological and catalytic applications. The unsubstituted parent ring of the system, 2,5-diazabicyclo[2.2.1]heptane itself, has not been structurally characterized. We herein report on the molecular structure of the parent ring in (1S,4S)-2,5-diazoniabicyclo[2.2.1]heptane dibromide, C5H12N22+·2Br−. The asymmetric unit contains two crystallographically independent cages of 2,5-diazabicyclo[2.2.1]heptane. Each cage is protonated at the two nitrogen sites. The overall charge balance is maintained by four crystallographically independent bromide ions. In the crystal, the components of the structure are linked via a complex three-dimensional network of N—H...Br hydrogen bonds.

The dinuclear Cu(II) complexes [Cu(en)(MAA)(µ-CH3COO)]2 (1) and [Cu(pn)(MAA)(µ-CH3COO)]2 (2) where MAA, en and pn are methacrylate, ethylendiamine and 1,3-propylendiamine, respectively, have been synthesized and characterized by elemental analysis, FT-IR and UV-Vis spectroscopy. The structures of the complexes have been determined by single-crystal X-ray diffraction analyses. In the dinuclear complexes 1 and 2 the two copper centers are five-coordinated and exhibit distorted square pyramidal geometries. The theoretical geometries of the studied compounds have been calculated by means of density functional theory (DFT) at the B3LYP/6-311+G(d,p)/LanL2DZ level considering effective core potential (ECP).

Methods of introducing a water-soluble biocide modifier, oligohexamethyleneguanidine hydrochloride, into epoxy-amine systems were studied. The obvious way is the introduction of the modifier in the waterborne epoxy-amine systems. However, this leads to cured systems with reduced mechanical properties. Introduction of oligohexamethyleneguanidine hydrochloride solutions in organic solvents into epoxy-amine systems allows obtaining a homogeneous system, but their application is limited by the presence of a volatile solvent. Finally, introduction of oligohexamethyleneguanidine hydrochloride solutions in a water-soluble amine curing agent into epoxy-amine systems has good prospects. It is shown that the analyzed modifier has good solubility in ethylenediamine, but poor solubility in oligooxypropylenediamine. It was found that the modifier is capable of interacting chemically with epoxy resins at 22°C to form an elastic insoluble material. In an epoxy-amine system with a more active hardener (ethylenediamine) oligohexamethyleneguanidine hydrochloride acts as a plastifier (flexibilizer). This significantly reduces the glass transition temperature of the matrix (from 53 to 37ºC).

The results of the study of various modification methods of polymer microspheres for their use in immunochemical reactions as bioligand carriers are reported. Ion etching and electron microscopy were used to show that the copolymer microspheres have a porous structure non-uniform in density. The Maillard reaction was used for the first time in the modification of copolymer microspheres by dextrans of different molecular weight as a simplest way of covalent immobilization of saccharides on their surface. The physicochemical properties of polystyrene-divinylbenzene and polyglycidyl methacrylate-ethylene glycol dimethacrylate microspheres modified with diamines and dextrans were determined for the first time. The conditions under which the bioligand (diphtheria toxoid) immobilized on their surface retained the native conformation and the diagnostics obtained on their basis have high sensitivity were revealed. [ABSTRACT FROM AUTHOR]

Heat-resistant polyhydroxyesters were obtained through polycondensation of 2-hydroxypropyl- 1,3-bis-ester of sulfoimide saccharin-6-carboxylic acid with some aliphatic diamines. Structures of the synthesized compounds were confirmed by infrared spectroscopy data. Thermal stability was studied by means of differential thermal analysis on a derivatograph of the Paulik-Paulik-Erdei system. Derivatographic studies showed that the synthesized polyhydroxyethers have a high thermal stability which decreases as a length of the aliphatic fragment in their composition increases. X-ray studies went to show that the obtained compounds were amorphous polymers. [ABSTRACT FROM AUTHOR]

• Diamine (DMAPA) and glycine (GLY) mixtures have high CO 2 loading capacity. • Ethanol was used to convert liquid absorbent and CO 2 into carbamates. • At low GLY-DMAPA concentration (0.1 mol/L) no product was formed. • Carbamates were generated at high concentration of GLY-DMAPA (0.5–2.0 mol/L). 3-dimethylaminopropylamine (DMAPA) and glycine (GLY) mixture was studied as a potential absorbent for carbon dioxide (CO 2) capture and utilization. The solubility of CO 2 in aqueous GLY-DMAPA solutions within the range of 0.1–2.0 mol/L (M) were measured experimentally using pressure differential technique. Utilization of CO 2 was also studied by mixing the CO 2 -saturated absorbent with ethanol. The final products obtained were characterized by using Fourier transform infrared (FTIR) spectroscopy and X-ray photoelectron spectroscopy (XPS). The solubility study revealed that the CO 2 loading capacity increased as pressure of CO 2 increased. In contrast, the loading capacity decreased when concentration of the absorbent and temperature in equilibrium cell increased. However, the total moles of CO 2 absorbed showed an opposite trend such that net CO 2 absorbed increased as concentration of absorbent increased. The chemical interactions between CO 2 and GLY-DMAPA molecules were studied by analyzing the changes of characteristic peaks observed form the FTIR spectra. For CO 2 utilization, the addition of ethanol as a reagent into 0.1 M CO 2 -saturated GLY-DMAPA solution did not produced any precipitate. Nonetheless, as the concentration of GLY-DMAPA increased from 0.5 M to 2.0 M, white precipitates were produced, indicated that the conversion of CO 2 into solid compounds occurred instantaneously after the CO 2 capture. The optimum concentration of GLY-DMAPA for CO 2 capture and utilization depends on the amount of solids generated and the CO 2 loading capacity of the absorbent. At 5 bar, the optimum concentration was found to be 1.0 M with 45 mg/g of solids recovered and CO 2 loading capacity of 1.6 mol CO 2 /mol absorbent. The final product was identified as carbamate salt based on the main characteristic peaks present on the FTIR and XPS spectra. [ABSTRACT FROM AUTHOR]

Initially, a novel series of mixed ligand Pd(II) complexes of 2H[1,4]benzothiazin-3(4H)-one (Hbto) and diamine or phosphine ligands were successfully prepared with yields of 61 to 92%. The treatment of Na 2 PdCl 4 with Hbto in acetone with 1:2 Pd to Hbto ratio affords cis -[PdCl 2 (Hbto) 2 ] (1) that delivers an appropriate entry into mixed-ligand Hbto complexes. The complex (1) was used as a precursor for preparation the complexes of the type [Pd(Hbto) 2 (κ2-diamine)]Cl 2 ; (diamine = en (2a), bipy (2b), phen (2c)) and [Pd(Hbto) 2 (κ2-diphosphine)]Cl 2 ; (diphosphine = dppm (3a), dppe (3b), dppp (3c), dppf (3d)). Likewise, the mono phosphine (PPh 3) was used to prepare the contrast complex with complex (1), however, to dissipate the suspicion that define complex [Pd(Hbto) 2 (PPh 3) 2 ]Cl 2 is present in the cis or trans structure, two methods were used to prepare this complex, both of which demonstrated that the cis is the preferred structure for the complex [Pd(Hbto) 2 (PPh 3) 2 ]Cl 2 (4). For all as-prepared complexes, the characterization techniques (molar conductivity, IR, 1H-, 13C-{1H}, 31P-{1H}NMR and elemental analyses) prove that the Hbto links to Pd(II) in a mono-dentate fashion through the exocyclic oxygen atom. To benefit from the complexes prepared, some as-prepared complexes (1), (2b) and (4) have been evaluated for their H 2 storage at 77 K after measuring the N 2 adsorption/desorption isotherms in order to get some information about BET surface areas of the samples. The results demonstrate that the selected prepared complexes were all able of storing the H 2 and among the complexes (1), (2b) and (4), (2b) was the best one and was able to store 5.4 wt% of H 2 under 70 bar and 77 K. Unlabelled Image • Synthesis and characterization of new Pd(II) complexes with 2H[1,4]benzothiazin-3(4H)-one and the mixed diamine or phosphine ligands. • Some of these complexes investigated for their BET surface areas. • H 2 storage capacity for some complexes were demonstrated. [ABSTRACT FROM AUTHOR]

The pyrimidines fused with pyrrole ring, pyrrolopyrimidines, showed broad applicability in medicinal chemistry. Herein, we synthesized the new derivatives (8 examples) of pyrrolo[1,2‐a]pyrimidine containing 1,3‐indandione skeleton by the use of triethylammonium thiolates, methyl iodide, and ketene aminals via a one‐pot three‐component reaction. [ABSTRACT FROM AUTHOR]