A simple approach was developed to efficiently graft diethylene triamine onto polystyrene waste using succinic anhydride as a tracer to remove nitrate anions from aqueous solutions. Infrared spectroscopic data showed characteristic signs at 3395 cm−1 and 1695 cm−1 corresponding to N-H and C=O (ester and amide), confirming the grafting of DETA onto PS. The zeta potential study showed that the PS-Succ-DETA adsorbent had a pHiep of 8.2, and its charge was positive when the pH was lower than the pHiep. Parameters affecting nitrate adsorption, such as dosage, initial concentration, pH, and contact time, were studied. The adsorption data corresponded well to the Langmuir isotherm with an R2 correlation coefficient of 0.998, and the adsorption capacity was found to be 195.65 mg/g. The adsorption kinetics of NO3− ions by PS-Succ-DETA corresponded perfectly to the PS-II model, with an R2 coefficient of 0.999. The negative value of ΔG (−10.02 kJ/mol), ΔH (−18.76 kJ/mol), and ΔS (−28.83 J/K/mol) indicates that NO3- adsorption is spontaneous exothermic and suggests a decrease in randomness at the solid-liquid interface during the adsorption. The mechanism of adsorption of nitrate ions onto PS-Succ-DETA occurs via electrostatic interactions and hydrogen bonds between the NO3− ions and the -NH2 and NH functions of PS-Succ-DETA.

Molecules with tuneable properties are well known for their applications in the material and bio-medical fields; nevertheless, the structural and functional tunability makes them more significant in diverse applications. Herein, we designed and synthesized a novel class of star-shaped molecules via incorporating two important functional groups, i.e., triazole and dithiocarbamate (DTC). The rationale behind selecting these two key functional groups is their diverse applications, e.g., DTC having applications for therapeutics, pesticides, and vulcanizing agents, and triazole having applications for anti-cancer, fungicides, anti-microbials, inhibitors, etc. The structure of the molecules was strategically designed in such a way that their overall structures are the same (central tertiary-amine and peripheral hydroxy groups), except the key functional group (DTC and triazole) in the respective molecules was different. Following synthesis and characterization, the influence of DTC and triazole groups on their bioactivity was compared via interacting with the most abundant proteins present in the blood, including serum albumin, trypsin, haemoglobin, and ribonuclease. From both the experimental and molecular docking studies, it was confirmed that the triazole molecule has a higher binding affinity towards these proteins as compared to the DTC molecule. In summary, two star-shaped DTC- and triazole-based molecules were synthesized and their bioactivity was compared via binding with blood plasma proteins.

[1.1.1]Propellane, a compound whose structure includes two saturated carbons in which all four bonds are directed into a single hemisphere, is of theoretical interest, but has also seen recent practical applications. Mono-, di-, and trisubstituted derivatives of this propellane (by substitution of its CH2 bridges with O, S, NH, CF2, CO, SO, and SO2) remain unknown despite several computational studies that have suggested some may be stable. In this study, we show that, in several cases, substituted propellanes are spontaneously formed upon the attempted computational optimization of the geometries of anionic bridgehead bromide precursors using the ωB97X-D/aug-cc-pVDZ DFT method. Spontaneous formation suggests that these propellanes are at lower energy relative to the precursors and, therefore, are promising synthetic targets. The success or failure to spontaneously form the propellane is considered in relation to the length and strain energy of the central bridgehead-bridgehead bond, as well as the total strain energy of each propellane.

Cardanol, a waste from the food industry and widely produced (1 Mt/y), has been used as a chain stopper during the polycondensation of short oil alkyd resins in order to replace benzoic acid. Then, phosphorylated cardanol has been added in order to both reduce solvent content and bring flame-retardant (FR) properties to the alkyd resins. The renewable carbon content of the formulations has been increased up to 23%. The impact of the introduction of phosphorylated cardanol molecules on the drying time and flexibility has been studied as well as the thermal and flame-retardant properties by differential scanning calorimeter, thermogravimetric analysis and pyrolysis-combustion flow calorimeter. The most effective flame-retardant coating that was associated with excellent FR properties and excellent coating properties has been obtained with phosphate-cardanol added at 2%wt of P. Indeed, the film properties were closed to the classical alkyd resin, the solvent content was reduced by 50% and the pHRR decreased by 42% compared to the reference alkyd resin.

High-quality academic publishing is built on rigorous peer review [...]

A series of 3-hydroxy-fluorene-2-carboxylate compounds were prepared from Michael addition of acetoacetate to 2-benzylideneindan-l-one followed by Robinson annulation and aromatization. In this reaction, we were able to isolate two Robinson annulation products and characterize them. This sequential reaction could proceed without the isolation of intermediates to give the desired products directly in reasonable yields.

The total synthesis of multifidene, a sex pheromone found in brown algae, is described. The synthesis features the highly enantioselective and diastereoselective addition reaction of an aldehyde to a nitroolefin in the presence of a Hayashi–Jørgensen catalyst and a Nef reaction initiated by visible light irradiation. These key reactions enabled the 11-step synthesis from commercially available compounds. The synthetic pheromones are examined with gametes.

1,2-Bifunctional ligands are rare, in general, which holds especially for those with a P-N linkage. Herein, we report on the synthesis of P-tert-butyl substituted aminophosphane W(CO)5 complexes 3a-f (a: R = R’ = H; b: R = H, R = Me; c: R = H, R’ = ally; d: R = H, R’ = i-Pr; e: R = H, R’ = t-Bu; f: R = R’ = Me) obtained via formal N-H insertion reactions of Li/Cl phosphinidenoid complex 2 into NH bonds of ammonia and different amines. The 1,2-bifunctionality of 3b was addressed in targeted regioselective deprotonation reactions leading to amidophosphane complexes M-4b or M/N(H)Me phosphinidenoid complexes M-5b, respectively (M = Li, K). Remarkable was the observation that reactions of M-4b and M-5b with MeI as the electrophile resulted in the formation of the same product 7b. The constitution of all the compounds has been established by means of NMR and IR spectroscopy and mass spectrometry. Two possible reaction pathways were studied in detail using high-level DFT calculations.

DFT calculations on the photoisomerization of 2,6-dimethylpyrazine allowed us to confirm the role of benzvalene isomers in the isomerization of hexatomic heterocyclic compounds. 2,6-Dimethylpyrazine in the excited singlet states can be converted into the corresponding Dewar isomers. If the S2 state is populated, two Dewar isomers can be obtained, while the S1 state allows the formation of only one of the possible Dewar isomers. Both Dewar isomers can be converted into the benzvalene isomer, that is, the precursor of 4,5-dimethylpyrimidine, the reaction product. In fact, the benzvalene isomer can be obtained from the Dewar isomers in processes that occur without an activation energy, and it is the more stable benzvalene isomers that can be obtained from the Dewar isomers. CASSCF study indicates the presence of a conical intersection allowing the direct formation of the benzvalene isomer.

Novel 2-amino bis(2-phosphonoacetic) acids were prepared by microwave irradiation of a mixture of amine, glyoxylic acid and phosphorous acid. The reaction takes place with various amines including primary and secondary amines and polyamines, but this reaction is more sensitive to steric hindrance of amine than the similar Kabachnik–Fields reaction. Amino acids can be also transformed into the expected bis(2-phosphonoacetic) acids, with the exception of tryptophan, which gives a β-carboline product.