Search

The name of Menshutkin is most frequently associated with his eponymous reaction (the quaternization of tertiary amines with alkyl halides). However, he made encyclopedic contributions to the field of reaction kinetics, where he carried out extensive studies of the effects of reactant structure on the rates of esterification of monohydric, dihydric and trihydric alcohols with monocarboxylic acids, and monobasic and dibasic carboxylic acids and anhydrides with monohydric alcohols. In these studies, he deduced an order of reactivity of alcohols in esterification on the basis of their reactions with acetic acid, and the effects of acid structure on the rates of esterification based on the reaction of the carboxylic acid with isobutyl alcohol. When his attention later turned to the substitution chemistry of amines, he defined the parameters that affected their reactions: anilines were less reactive than alkylamines, secondary more reactive than primary amines, and the reaction was accelerated by replacing benzene as a solvent with alcohols. The wide-ranging work of Menshutkin, the physical organic chemist, is discussed.

The following salts have been synthesized and structurally characterized: Na2[IrF6]·2H2O (C2/m, a = 6.6327(4), b = 10.0740(6), c = 5.9283(5) A, β = 122.3880(10)°) and Na3[IrF6]·2H2O (R-3, a = 7.5963(3), b = 7.5963(3), c = 9.8056(4) A) (for the first time) by single-crystal X-ray diffraction; the unit cell parameters of a tetragonal phase (P42/mnm, a = 5.005(2), c = 10.074(4) A) of the stable α-Na2[IrF6] were determined for the first time; and the unit cell parameters of β-Na2[IrF6] (P321, a = 9.332(4), c = 5.136(2) A) and Na3[IrF6] (P21/n, a = 5.567(4), b = 5.778(4), c = 8.017(2) A, β = 90.41(2)°) were determined using powder X-ray diffraction (PXRD). The data of the thermal stability was obtained by differential thermal analysis (DTA) for all substances. The presence of Na3[IrF6]·H2O monohydrate is predicted. H2[IrF6] was prepared in a solution and was demonstrated to behave as a strong dibasic acid.

Several attempts have been made to obtain aliphatic dicarboxylic diesters from esterification reaction to develop the biomass-derived platform molecules and green manufacturing processes. In this paper, Na3(H2O)6[AlMo6O18(OH)6], an Anderson-type polyoxometalate, firstly, was reported as a catalyst for diester synthesis from dicarboxylic acid to diester which showed an well productivity and selectivity characterized by 1H and 13C. Response surface methodology (RSM) integrated with the desirability function approach was used to determine the best operative conditions, and the optimal reaction parameters for maximum dipropyl succinate yield (77 ± 2.5%) were identified as 1.19 mol.% catalyst loading, 4.9:1 propanol/succinic acid ratio, 113 °C, and 9.6 h. Three batches of tests were carried for catalyst recycling with 78–75% yield even after 6 cycles of esterification. In addition, the substrate carbon chain was increased for investigation of substrate scope achieving satisfactory results and all products were characterized by 1H and 13C nuclear magnetic resonance spectroscopy.

Attempts have been made to synthesis titanium dioxide (TiO2) nanoparticles using titanium (IV) complexes of Schiff base (TiOL) as a precursor where Schiff base ligand (L) act as a dibasic tetradentate one. TiO2 nanoparticles were synthesized by the direct calcination of titanium complexes at 500 °C for 3 hours. The analytical tools such as FT-IR, XRD, EDS, and SEM provided evidences in favor of the formation of TiO2 nanoparticles. Antimicrobial study showed that all prepared TiO2 nanoparticles have inhibition capacity on the growth against selected plant pathogenic fungi as well as some selected human pathogenic bacteria. Moreover, these TiO2 nanoparticles have catalytic capacity for the remarkable degradation (54.0%) of organic dye (Mordent brown 48) as well as industrial dye solutions.

Volatile organic compounds (VOCs) emitted from building and furnishing materials represent a major concern of indoor air quality, in particular in new buildings. We carried out multiweek nontargeted VOC measurements in 10 new apartments in Beijing, China, using online chemical ionization mass spectrometry. Dimethyl esters of succinic, glutaric, and adipic acids, which are rarely known for their presence in indoor air, were identified in three apartments. The identification was confirmed using authentic standards and by gas chromatography/mass spectrometry analysis. Despite varying concentrations, the three compounds exhibited largely consistent ratios across the three apartments and throughout the observation periods. The observed ratios resemble chemical composition of dibasic esters (DBE), which are a solvent mixture of the three compounds and have been used in the coating industry. A field “sniffing” experiment further confirms DBE emissions from the coatings of some wooden furniture in at least one apartment. The average airborne DBE concentrations in the three apartments were 41, 5, and 4 μg/m³, respectively, exceeding the screening level of 1 μg/m³ recommended by the Michigan Department of Environmental Quality, United States. In the context of fast-growing DBE usage, the current results suggest that DBE might be emerging indoor air pollutants and merit further investigation.

Dibasic acids (DBA) with benzene rings having substituents and connected by a sulfurcontaining bridge exhibited radioprotective effectiveness when administered in non-toxic concentrations to laboratory mice 1 h before γ-irradiation in a lethal dose of 8 Gy. The correlation of protonophore activity on bilayer lipid membranes with radioprotective (in mice) and uncoupling activity (in mitochondria) indicates a molecular protonophore uncoupling radioprotective mechanism of DBA action on mitochondria, which manifests in temporary partial inhibition of energy production. The effectiveness of DBA depends on the position and the degree of dissociation of OH-groups and increased in the presence of a sulfur-containing bridge and substituents in the series Br—>Cl—>NO2—>COOCH3—>COOH—. The higher radioprotective effect was observed for more effective uncouplers of the processes of oxidative phosphorylation and respiration of mitochondria, DBA1 preparations with OH-groups in the 2nd position of the benzene rings (80-100%), than for DBA2 with OH- in the 4th position (40-60%). The radioprotective effect of DBA was related to their antioxidant activity during and after irradiation to a lesser extent than with their uncoupling efficiency. At the cellular level, the radioprotective mechanism of DBA is related to temporary hypoxia and inhibition of metabolism leading to inhibition of generation of ROS, radicals, and LPO products.

Remediation via adsorption process has been proven to be one of the best water treatment technologies globally. Many adsorbents, including agricultural wastes, have been considered for the removal of a variety of pollutants from water. However, most of the studies reported in the literature used metal concentrations below 1000 ppm. It is also known that initial metal concentrations in polluted aqueous solutions, as well as metal and adsorbent type, are some of the factors that affect metal removal. Therefore, this project examined the remediation of water contaminated by 1000 ppm of lead, zinc, copper, magnesium, and calcium ions using wood ash, sodium hydrogen phosphate (dibasic), and sodium carbonate (dibasic). Comparative analysis of the results showed the order of order of metal removal by the adsorbents as: dibasic phosphate (Ca > Cu > Pb > Zn > Mg); dibasic Carbonate (Pb ~ Ca > Zn > Cu > Mg); Wood ash (Mg > Cu > Zn > Pb > Ca). These results suggest that metal and adsorbent type as well as the inherent chemical properties of these metal cations may contribute to the varying binding affinity of the metals to the adsorbent ligand(s) and thus, affect the extent of metal removal. It is equally worthy to note that wood ash more effectively removed hardness metals (Mg and Ca) from water than the inorganic phosphate and carbonate ions.

Four Schiff bases (H2L1 to H2L4) have been synthesized by the con­densation between o-aminophenol and unsaturated diketones (1,5-diarylpent-4--ene-1,3-diones). Analytical, IR, 1H NMR and mass spectral data revealed their existence in the imine-enamine form. Dibasic tetradentate coordination of the Schiff bases in their ML complexes [M = Cu(II), Ni(II), Co(II), Zn(II), Cd(II), and Hg(II)] has been established on the basis of physical, analytical and spectral data. The fluorescent studies of H2L4 show that fluorescence emission maxima shift with increase in polarity and hydrogen bonding ability of the solvent. Paramagnetic Cu(II), Ni(II) and Co(II) ions decrease the fluorescence intensity with increase in concentration of the metal ion while diamagnetic Zn(II), Cd(II) and Hg(II) ions have very little influence on the intensity of fluorescence of the Schiff base H2L4 .

This study is focusing on the comparative study of arsenite and arsenate adsorption from the water via indigenous iron ores. The Sindh and Punjab provinces of Pakistan are badly affected by Arsenic (As) toxicity as the people are consuming arsenic contaminated groundwater. The aim of this study is to investigate the effect of anions on adsorption of arsenite As(III) and arsenate As(V). Impact of pH, contact time, adsorbent dose and shaking speed on adsorption of arsenite and arsenate is studied with the two selected iron ores from Hoshi and Shikarap from Balochistan. Hoshi and Shikarap ores exhibited higher As(III) and As (V) adsorption, respectively thus selected for further removal studies. Hoshi iron ore without sodium carbonate yields higher adsorption as compared to the samples with 100 mg/L and 1000 mg/L sodium carbonate in both As(III) and As(V). Hoshi ore exhibited the highest adsorption of 85% for As (V) without sodium phosphate dibasic and 83% for As(III). Shikarap ore for As(V) adsorbs 75% without sodium phosphate dibasic and 67% adsorption for As(III) without sodium phosphate dibasic. Shikarap ore with sodium silicate at 100 mg/L adsorbs 62% As(III) and at 1000 mg/L adsorb 52% As(III). Shikarap ore As(V) adsorption decreases from 75% without sodium silicate to 70% at 100 mg/L and even lower adsorption of 65% at a higher concentration of 1000 mg/L.

Cocrystallization has matured into an established technique for fine-tuning the physicochemical properties of active pharmaceutical ingredients (APIs). This technique has been adopted by pharmaceutical drug companies, with increasing numbers of cocrystal-based drug products now entering the market. Surprisingly, however, studies into the formulation aspects of cocrystal-based drugs are relatively few and far between compared to the vast literature on their design, synthesis, and characterization. We herein report the results of our investigations into cocrystal–excipient interactions in water that determine the dissolution properties of cocrystals in formulation by a combination of molecular dynamics (MD) simulation and experimental approaches. Two cocrystals of an antirheumatic drug, leflunomide (LEF) with 3-hydroxybenzoic acid (HBA) and 2-picolinic acid (PIC), were assessed in formulation with the frequently used excipients lactose and dibasic calcium phosphate (DCP). For comparison, the dissolution of neat LEF formulations with these excipients was also evaluated. The parameters deduced from MD simulations, such as solvent-accessible surface area, intermolecular hydrogen bonds among formulation ingredients and water, and interaction energy between the API (or cocrystal) and water were found to be essential indicators in the prediction of cocrystal formulation dissolution trends. It was found that the presence of lactose as an excipient improved the dissolution of the cocrystal formulation compared to the neat cocrystals, most notably for the LEF-PIC cocrystal. In contrast, DCP was seen to have a detrimental effect on the dissolution of cocrystal formulations, all exhibiting lower dissolution than their neat cocrystal counterparts and LEF. Careful analysis of these results revealed that the nature of the excipient plays a significant role in the dissolution properties. While the improved dissolution of the lactose formulations was attributed to its hydrophilic nature, the ionic and hydrophobic nature of DCP was likely responsible for its detrimental effect. The results of the MD simulations were found to be in excellent agreement with the experimentally observed dissolution hierarchy.

In a previous study, it was demonstrated that a novel deep eutectic solvent (DES), composed of lactic acid and sodium citrate dibasic at a molar ratio of 15:1 (LA-SCDB15), was a high-performing system with regard to polyphenol extraction from the medicinal plant Salvia fruticosa Mill. (Greek or Cretan sage). However, an issue of particular importance that should be addressed is the stability of the extract in this novel liquid since the information available to-date on extract stability in DES is rather limited and inconclusive. In this frame, this study was undertaken to generate extracts of S. fruticosa with LA-SCDB15 (a 77/23 w/w mixture of DES with water) and examine their stability in this solvent. S. fruticosa extracts exhibited remarkable stability under both accelerated and long-term conditions, and the antiradical activity and the ferric-reducing power of the extracts were shown to suffer virtually trivial modifications. Further analytical examination with liquid chromatography-diode array-tandem mass spectrometry assured that the major polyphenolic phytochemicals occurring in Salvia fruticosa extracts underwent non-significant changes and remained practically intact. It was concluded that the neoteric DES LA-SCDB15 may provide outstanding stability in polyphenol-containing extracts and its testing on other plant extracts is proposed as a further step towards revealing its stabilizing potential.

The liquidus lines of binary systems of dibasic carboxylic acids HOOC–(CH2)n–COOH (n = 3, 4, 7, 8) and eutectic coordinates were calculated by the Schrӧder–Le Chatelier equation. The experimental studies were performed by differential thermal analysis on a DSC heat flux microcalorimeter. Five or six mixtures with different contents of components were studied in each system. The phase diagrams were constructed based on the set of DSC data. The experimental melting temperatures and the composition of binary eutectics were compared with the calculated values. All the systems were of the eutectic type. A theoretical analysis of the solubility of the acids was performed, and the equations of solubility of acids in water were obtained. The eutectic composition of the pentanedioic–hexanedioic acids system was chosen based on the analysis of the solubility data; it can be used to obtain anodic coatings on aluminum. For the eutectics of the system, the solubility in water was experimentally studied at temperatures from 20 to 60°C. The composition of electrolyte for aluminum anodization was developed: eutectic mixture of pentadioic and hexanedioic acids, ethanedioic acid, and water. The temperature and time of aluminum anodization were recommended.

In a systematic study of the extraction of gold(III) in acidic chloride solutions by a number of aliphatic esters with the focus on dibasic esters, it was found that di- or tribasic esters are more...

This study was carried out to evaluate the effect of ammonium sulfate, calcium chloride, potassium dibasic phosphate and sodium carbonate on inhibiting mycelial growth of Alternaria alternate (Fr.) Keissler, Helminthosporium sp., Stemphylium botryosum Wallroth,and Curvularia lunata (Wakker) Boedijn isolated from lettuce (Lactuca sativa Folium.) leaves. The sodium carbonate and ammonium sulfate strongly inhibited mycelial growth and spore germination. Potassium dibasic phosphate and calcium chloride inhibited mycelial growth to a less extent. Sodium carbonate (25mM) decreased mycelial growth of A. alternate by 58.9%, Helminthosporium sp. by 58.8%, S. botryosum by 78.5% and C. lunata by 40.0%. The folpet fungicide used variably decreased growth of fungi in a range varied between 43.5% and 87.5% at 5ppm concentration. The effective concentration (EC50) figures indicated that sodium carbonate and ammonium sulfate caused more inhibition to A. alternata, Helminthosporium sp., S. botryosum and C. lunata. Lower concentration of potassium dibasic phosphate and calcium chloride showed lower effect. In general, the most effective chemicals used to control lettuce foliar diseases were sodium carbonate, ammonium sulfate, calcium chloride and potassium dibasic phosphate that decreased leaf spot severity. Sodium carbonate had a higher inhibiting activity against foliar diseases of lettuces. Expression of defense related enzymes involved in lettuce induced tolerance against infection was emphasized. The greater hydrolysis of plant cell walls by A. alternata, C. lunata, Helmithosporium sp. and S. botryosum was attributed to greater of polyglacturonase (PG) secretion.

New mixed ligand complexes of nickel(II) were synthesized by using dibasic H/5-bromo-/5-chloro-/4-hydroxy-2-hydroxybenzophenone-thiosemicarbazones (L1–4H2) and [Ni(PPh3)2Cl2]. The ligands and complexes were characterized by cyclic voltammetry, infrared, 1H and 31P NMR spectroscopy techniques. Crystallographic analyses of the 5-bromo-substituted (2) and 5-chloro-substituted (3) complexes as representatives were performed and so confirmed the ONS chelate structure and presence of PPh3 as co-ligand in the complexes. To reveal the antioxidant properties of the compounds, TEAC values (by CUPRAC method) were determined along with free radical-scavenging activity (by DPPH method). The compounds bearing 4-hydroxy substituent, L4H2 and complex 4 were the most effective compounds. The relationship between structure and antioxidant capacity in the context of benzophenone substituents and nickel(II) center was evaluated. Electrochemical results revealed that all complexes displayed metal-centered and ligand-centered redox processes. The antioxidant capacities of complexes were well correlated to electrochemical parameters.

Acid fracturing is an effective method to develop ultra-low permeability reservoirs. However, the fast reaction rate reduces the effect of the acid fracturing and increases the near-well collapse risk. Therefore, it is necessary to retard the acid–rock reaction rate. In this work, we synthesized an acid-resistant Gemini zwitterionic viscoelastic surfactant (named VES-c), which has good performances such as temperature resistance, salt resistance, and shear resistance. Besides, a low concentration of VES-c increases the viscosity of the acid solution. The CO2 drainage method was used to measure the reaction rate between the dibasic acid and dolomite/broken core. We find that the dibasic acid containing 0.3% VES-c retards the dolomite reaction rate of 3.22 times compared with only dibasic acid. Furthermore, the dibasic acid containing 0.3% VES-c exhibits uniform distribution and is not easy to adhere to the solid surface. The VES-c also is favorable to reduce the formation of amorphous calcium carbonate. Retarding the rate of acid–rock reaction and enhancing the acidification are mainly attributed to VES-c's salt-tolerance, anti-adsorption, and the property of increasing the viscosity of the solution. Hopefully, this kind of surfactant retarding reaction rate is applied to other acid–rock reactions.

Volatile organic compounds (VOCs) and Semi-Volatile Organic Compounds (SVOCs) arise from the chemicals used in the various stages of the leather manufacturing process. An important aim of the tanning industry is to minimize or eliminate VOCs and SVOCs, without lowering the quality of leather. This paper shows the development of a new headspace-solid phase micro extraction coupled with gas chromatography–mass spectrometry (HS-SPME/GC-MS) method for the identification of VOCs and SVOCs emitted by newly designed polymers for the leather finishing operation. These new polymers are polyurethane resins designed to reduce the VOC and SVOC concentration. This method enables a simple and fast determination of the qualitative and semi-quantitative content of VOCs and SVOCs in polyurethane-type finishing resins. The chemicals that are of concern in this paper are the following: Dipropylene glycol Monomethyl Ether (DPGME), DBE-3 (a mixture of dibasic esters) and Triethylamine (TEA). The test conditions that have been determined to carry out the HS-SPME assay are the following: incubation time (2 hours), extraction temperature and time (40°C; 5 minutes) and the desorption conditions (280°C, 50 seconds). Ten samples of laboratory scale resins were tested by HS-SPME followed by gas chromatography (GC-MS). DPGME and DBE-3 (a mixture of dimethyl adipate, dimethyl glutarate and dimethyl succinate) have been identified effectively. The compounds are identified by a quantitative method using external calibration curves for the target compounds. The technique is not effective to determine the TEA compound, since the chromatograms shown poor resolution peaks for the standard.

SLC6A14 (ATB0,+) is a sodium- and chloride-dependent neutral and dibasic amino acid transporter that regulates the distribution of amino acids across cell membranes. The transporter is overexpresse...

In this work, the adsorption capacity of Cu2+, Co2+ and Cr3+ by synthetic dibasic calcium silicate hydrate sample as well as its thermal stability was examined. The synthesis of dibasic calcium silicate hydrate was carried out in unstirred suspensions, when CaO/SiO2 molar ratio of primary mixture was equal to 1.5 and the duration of isothermal curing at 175 °C temperature was 16 h. Afterwards, metal ions were incorporated into the synthesis products; the experiments were carried out at 25 °C temperature by stirring 5 g of synthetic dibasic calcium silicate hydrate in 500 mL of Co(NO3)2·6H2O, Cr(NO3)2·9H2O or Cu(NO3)2·3H2O solutions containing 1 g of Co2+, Cr2+ or Cu2+ dm−3 for 30 min. It was obtained that after adsorption all metal ions (100 mg Me2+ g−1) were intercalated into the structure of synthesis products. In situ X-ray diffraction study on the thermal stability of synthesized compounds was performed in a modular temperature chamber from RT to 1000 °C temperature. The obtained results were confirmed by XRD, STA, FT-IR, AAS and SEM methods.

Polyaniline (PANI) conductive polymer is a unique energy storage electrode and sensor material. In this article, we report the use of electrochemistry as a quick and easy method to prepare PANI films, which are used as electrode materials to detect the selectivity to various acids. The sample was characterized and tested by XRD, scanning electron microscopy (SEM), BET, and cyclic voltammetry (CV). Various electrochemical parameters were measured and compared for various acids. As an electrode and sensor material, PANI film has different degrees of redox peaks for monobasic acid, dibasic acid, organic macromolecular acid, and inorganic acid. This type of sensor shows good repeatability and reproducibility, so this type of conductive polymer can be used as a sensor material to detect the minimum concentration of acid.

Layered double hydroxides (LDH) of general formula Ni1-x Alx(OH)2(A)x/2. mH2O were obtained by a co-precipitation method at constant pH, using succinate (C4H4O42−), adipate (C6H8O42−) and sebacate (C10H16O42−) as compensation anions and two x values, 0.3 and 0.5. The formation of NiAl LDH was evidenced, although in the Al-richer samples carbon analysis and solid-state 27Al NMR spectroscopy indicated the segregation of a small amount of an aluminum-containing phase. To prepare NiAlMo LDH, the original compensation anions were replaced by heptamolybdate ion using an anion exchange method. The results showed almost complete anion exchange in most samples, with small amounts of residual organic material, evidencing easy removal of the aliphatic dibasic anions as compared with terephthalate. The samples were characterized by FTIR, XRD, ICP-OES, CHN and Raman and 27Al MAS solid-state NMR spectroscopies.

The reaction of dibasic tetradentate ONNO donor Mannich bases, derived from ethylenediamine and 2,4–di–tert–butylphenol (H2L1) (I), 2,4–di–methylphenol (H2L2) (II), 2–tert–butyl–4–methylphenol (H2L3) (III) and 2,4–di–chlorophenol (H2L4) (IV), with UVIO2(MeCOO)2·2H2O in a 1:1 M ratio in refluxing MeOH gave the corresponding mononuclear trans-dioxidouranium(VI) complexes of the type trans-[UVIO2L(MeOH)] (H2L = H2L1 to H2L4) (1–4). The synthesized complexes are stable in air, reddish-brown in color and soluble in most solvents. These complexes are characterized by elemental analysis, various spectroscopic (FT-IR, UV/Vis, 1H and 13C NMR) techniques and single-crystal X-ray analysis of 3 and 4. The complexes adopt distorted pentagonal bipyramidal geometry around the metal centre. The ligand acts as tetradentate, coordinating through two phenolato oxygen and two imino nitrogen atoms; two oxido groups are trans to each other. These complexes are used as catalysts to study the oxidative bromination of thymol and styrene. The catalytic oxidative bromination of thymol resulted in the formation of three products namely, 2-bromothymol, 4-bromothymol and 2,4-dibromothymol while oxidative bromination of styrene gave two products, 2-bromo-1-phenylethane-1-ol and 1-phenylethane-1,2-diol. In order to find out the optimized reaction conditions for the fixed concentration (10 mmol) of substrate, effects of different amounts of catalyst, KBr, HClO4, and oxidant (H2O2) have been investigated. Under the optimized reaction conditions, all the complexes have shown good catalytic potentials for the oxidative bromination of substrates, establishing the functional similarity to vanadium dependent haloperoxidases. Changes in the UV–visible absorption spectra of dioxidouranium(VI) complexes upon addition of H2O2 suggest the formation of the corresponding oxidoperoxidouranium(VI) complexes.

The limestone used at the Pasargadae World Heritage Site in Iran, an outstanding open-air architectural heritage site dating from the Achaemenid period (sixth century BC), has suffered weathering due to interaction with the environment. It was built out of beige limestone that today shows scaling and pitting decay patterns. Two inorganic consolidating products that are very promising: nanolime and dibasic ammonium phosphate (DAP) were considered for the consolidation of the limestone. Consolidation treatments were conducted on samples from a quarry and applied using a paintbrush with 50% nanolime dispersion in isopropyl alcohol and 1.0 M DAP water solution. Superficial consolidation was evaluated by means of a micro-drilling resistance test, and color changes were assessed by spectrophotometry. The microstructure of the treated samples was observed using FE-SEM. The efficacy of the two consolidation treatments was also assessed by testing their hydric properties and durability (hydric tests, freeze-thaw, and salt crystallization cycles). The compactness in the altered samples was monitored by measuring the ultrasound propagation velocity. We found that the superficial resistance increased in a similar way with both treatments. However, spectrophotometry revealed a yellowish color in the samples treated with DAP. During FE-SEM observations, some diffused microcracks were detected on the surface of DAP treatment. When subjected to accelerated aging tests, both treatments managed to postpone the formation of the first microcrack during the freeze-thaw test and both showed outstanding stability during salt crystallization cycles. In conclusion, the nanolime product seems to be more compatible with beige limestone because it does not affect its aesthetic qualities (color, lightness, and a homogeneous layer formed on the surface of the stone). Moreover, previous research found that lime has a low propensity for biological growth. This supports its use as a consolidating product for the stone used in open-air archeological sites that are prone to microbial growth, such as the beige stone used in the Pasargadae WHS.

Oleochemical-based long-chain diesters are potential organic phase change materials convenient for thermal energy storage. The development of efficient and green methods is an important requirement for the preparation of these environmentally friendly compounds, which also are finding wide industrial application. Thus, in the present work, a series of dibasic acid esters were synthesized through ionic liquid catalyzed scalable chemical esterification or transesterification reactions in a solvent-free medium. The starting compounds, dicarboxylic acids or their methyl esters and fatty alcohols or cholesterol, were reacted in the ratio of 1:2 respectively and the synthesized esters were characterized by FT-IR, 1 H NMR, and 13 C NMR.

A new series of diorganotin(IV) complexes of 4-((2-hydroxybenzylidene)amino)-[1,1′-biphenyl]-3-ol (H2L1), 4-((2-hydroxy-5-nitrobenzylidene)amino)-[1,1′-biphenyl]-3-ol (H2L2), 4-((3-bromo-2-hydroxy-5-nitrobenzylidene)amino)-[1,1′-biphenyl]-3-ol (H2L3) and 4-((3,5-dibromo-2-hydroxybenzylidene)amino)-[1,1′-biphenyl]-3-ol (H2L4) Schiff base ligands with general formula R2SnL (where R = Me, Et, Bu and Ph) were synthesized. Structural aspect of these synthesized compounds have been described with the help of elemental analysis and spectroscopic techniques like FT-IR, UV–Vis, NMR, Mass and fluorescence. Schiff bases coordinated to tin metal as dibasic tridentate ligand through imine nitrogen and two phenolic oxygen atoms forming pentacoordinated complexes. Metal complexes gave low molar conductance value describing their non-electrolytic nature. Thermal decomposition of the complexes resulted in the formation of SnO2 as end product. The in vitro antimicrobial activities have been evaluated against Gram positive bacteria, Gram-negative bacteria and two fungal strains. The screening evaluation showed that organotin(IV) complexes have better antimicrobial activity. The free radical scavenging ability of the compounds was invest by in vitro antioxidant assay involving DPPH radical and was found to be moderately good. The anti-inflammatory activity was done by egg albumin method and percentage inhibition of protein denaturation was calculated. By comparing the biological activities of the synthesized compounds it was found that metal complexes were more potent than the free ligands and compounds 16, 20 were having more potential as drugs.

Hexamethylenediammonium glutarate was synthesized by glutaric acid recovered from mixed dibasic acid and 1, 6- hexanediamine in aqueous solution and characterized by fourier transform infrared spectroscopy and nuclear magnetic resonance. Its thermal properties were evaluated via differential scanning calorimetry. At the same time, the solubility of hexamethylenediammonium glutarate in four mono-solvents (water, methanol, acetic acid and ethylene glycol) and four binary solvents (methanol + ethanol/2-propanol/1-butanol/DMF) were determined by dynamic method at atmospheric pressure. It turns out that the solubility of hexamethylenediammonium glutarate in the selected solvents increases with the temperature rising in the investigated temperature range. Moreover, the solubility data was correlated by the modified Apelblat model, the λh model, the e-NRTL model and the Jouyban–Acree model. The results showed that the experiment data was better in agreement with the values calculated by the modified Apelblat model in mono-solvents and binary mixed solvents. In addition, the dissolution thermodynamics were based on the van't Hoff equation. The results demonstrated that the dissolution processes of hexamethylenediammonium glutarate in the selected binary solvents were the non-spontaneous and endothermic processes. Therefore, the solubility data and the dissolution thermodynamic properties provide the basis for the separation and purification of hexamethylenediammonium glutarate by crystallization.

A possibility to use acid-type phosphoryl-containing podands with diethylene glycol polyether chain, which differ in substituent at the phosphoryl group, as extractants for the recovery of U(VI), Th(IV), and rare earth elements(III) from nitric acid solutions has been studied. Features of the effect of HNO3 concentration on U(VI) and Th(IV) extraction with solutions of the phosphoryl-containing podands in dichloroethane has been revealed. Uranium(VI) is extracted as a normal intracomplex salt of dibasic acid UO2L3 with chelate coordination of both POO− groups to one cation. Thorium(IV) produces a complex as a normal intracomplex salt of composition Th(L3)2 where two bivalent anions of ligand acid are coordinated via all four POO− groups to Th(IV) cation. Sorption of U(VI), Th(IV), and REE(III) by impregnated sorbent based on LPS-500 polymer with 1,5-bis[2-(oxyethoxyphosphoryl-4-ethyl)phenoxy]-3-oxapentane from 0.052 and 3.52 mol/L HNO3 has been studied. It has been established that the obtained sorbent shows high selectivity in the separation of U(VI), Th(IV), and REE(III). The separation factor for uranium(VI) and europium(III) (βU/Eu) has been found to be 202 and ∼55000 upon sorption from 3.52 and 0.052 mol/L HNO3, respectively, at V/m = 500 mL/g. At thorium(IV) sorption from 3.52 and 0.052 mol/L HNO3, βTh/U = 66 and ∼5050, respectively.

Dissociation and complexation with Cu(II) cation is studied for phosphoryl-containing podands (tetrabasic 1,5-bis[2-(dioxyphosphoryl)-4-ethylphenoxy]acidic-type-3-oxapentane (H4LP) and dibasic 1,5-bis[2-(oxyethoxyphosphoryl)-4-ethylphenoxy]-pentane (H2LP)) and their carbonyl analog (polyether dibasic acid 1,5-bis[2-(oxycarbonylphenoxy)]oxapentane (H2LC) in water in the presence of 5% dimethylformamide potentiometrically, spectrophotometrically, and conductometrically. Phosphoryl podands exhibit good complexing properties and can selectively bind metal cations. The dissociation constants are determined and the distribution diagram of ionized species of the compounds under study depending on pH is plotted. The molar ratio between the metal and podand in all complexes is found to be 1 : 1. The stability constants of complexes with Cu2+ cation are calculated. The most stable copper(II) complexes are formed with the tetrabasic podand.

Transition metal complexes of Mn(II), Co(II) and Cu(II) with dibasic tridentate Schiff base derived from the condensation of thiosemi-carbazide with acetoacetanilide as primary ligand and 1-hydroxy-2-naphthoic acid as co-ligand have been synthesized. The mixed ligand complexes of the above mentioned metal ions were characterized by analytical, magnetic and electronic spectral study. The transition metal complexes were also evaluated for antifungal activity against Drechslera tetramera, Fusarium oxysporum and Aternaria alternata at different concentrations.

Colloidal silica has wide applications and the global demand of specialty silica is continually increasing. Therefore, it is significant to develop a synthetic method that is simple, versatile, energy-saving, ecologically benign, and easily scalable. Biomimetic synthesis of colloidal silica represents a promising strategy; however, it often requires the synthesis or extraction of specialized macromolecules. In this paper, we present a novel aqueous, one-pot, and green route for synthesis of organosilica nanoparticles. The reaction systems contain only water, an organosilane precursor, a salt, and a commonly used surfactant or amphiphilic polymer. The reaction was performed at ambient conditions without adding any additional solvent, energy, and harsh chemicals. The key findings include the novel identification of 5 salts (i.e. nitrite, fluoride, dibasic phosphate, acetate, and sulfite) that can catalyze organosilica condensation and the resulting formation of nano-colloids. Moreover, the presence of amphiphilic molecules is essential for salt catalysis at low salt concentrations and at nearly neutral pH. Solid-state NMR and in-situ ATR-FTIR studies confirmed that organosilica condensation is highly efficient under the mild reaction condition. In conclusion, the present study demonstrates that "soft" interaction between salts and surfactants (or polymers) can be utilized to construct an effective platform for synthesis of "hard" organosilica particles. The proposed method is generic and applicable to a wide range of commonly used surfactants (viz. non-ionic, anionic, cationic) and amphiphilic polymers, as well as to organosilanes with various hydrophobic functional groups (e.g. mercaptopropyl, vinyl, and methyl).

Deformation is the material property that is a key for successful tablet formulation. Still, a quantitative method for assessing the change in particle size as a result of compression is lacking. The purpose of this study is to introduce a method for quantifying fragmentation after tableting. Different size fractions of dibasic calcium phosphate, microcrystalline cellulose, lactose, and starch were blended with magnesium stearate and compressed into tablets. The compressed particles were recovered from the tablets by manual grinding, which was possible by the addition of magnesium stearate. The recovered particles were subjected to scanning electron microscopy and particle size distribution (PSD) analysis. Fragmentation was quantified by characterizing the change in PSD. PSDs of the compressed samples with increasing compression pressures were analyzed, and more specifically, the particle sizes from the inflection point were used to generate a fragmentation profile. The fragmentation profiles of dibasic calcium phosphate and lactose showed extensive fragmentation during tableting; microcrystalline cellulose fragmented slightly, whereas starch did not fragment at all. The results furthermore showed that the mechanical strength of the tablet was highly dependent on fragmentation, as the mechanical strength did not start to increase before almost all fragmentation had occurred. Hence, by using this method, it is possible to quantify at which compression pressure and to which degree materials fragment during the tableting process.

Five novel nanometric homo-binuclear complexes have been synthesized by the reaction of Cu(II), Co(II), Ni(II), Mn(II) and Zn(II) salts with a new azo dye 4-(2,4-dihydroxy-phenylazo)-N-thiazol-2-yl-benzenesulfonamide (H2L) with the aim to develop neoteric antitumor drugs. H2L has been prepared by coupling of sulfathiazole with resorcinol in order to comprise the bioactivities of sulfonamide part and azo group in the formed metal complexes which greatly enhance their bio-efficiencies. The ligand and complexes have been fully characterized using various spectral and analytical techniques. The obtained data indicated a dibasic tetradentate nature of ligand which coordinated via deprotonated phenolic oxygen, one azo group nitrogen, N-atom of thiazole ring, and sulfonamide oxygen forming tetrahedral geometry around the central metal ions. XRD data confirmed the crystalline nature of ligand and amorphous nature of the complexes. TEM images proved nanometeric size of complexes particles. The data of antimicrobial screening revealed that metal complexes are more potent than the azo dye ligand against varies micro-organisms. Anticancer activities of all compounds were evaluated against human liver carcinoma cells (HepG-2) and breast carcinoma cells (MCF-7). Cu(II) complex showed the highest anticancer activity (IC50 = 23.6 µg/ml) against HepG-2 cells. Co(II) complex displayed the greatest anticancer activity (IC50 of 7.67 µg/ml) contra MCF-7 cells. Electronic absorption and viscosity studies proved that H2L and complexes interact with DNA by intercalation binding and electrostatic force groove binding modes, respectively. The results of this study ascertain that Cu(II) and Co(II) complexes are very favorable candidates for further applications in cancer therapy.

The current study investigates the development of extemporaneous preparation of hot melt extruded diclofenac sodium (Df-Na) pellets processed with glyceryl dibehenate (Compritol® 888 ATO) and dibasic calcium phosphate anhydrous (Fujicalin®) as carriers for pediatric applications. The extruded lipidic pellets were physicochemically characterized in order to examine the state of the active substance within the extruded formulations where Df-Na was found to retain its crystallinity but partially solubilized by glyceryl dibehenate. Furthermore, the dissolution rates of extemporaneous Df-Na pellets were assessed at gastric (pH 1.1 and simulated gastric fluid pH 1.6) and intestinal conditions (pH 5.5) to investigate the effect of food grades such as yogurt, apple sauce, mashed potato and hypromellose 2910. Extemporaneous compositions appeared to have a significant effect on Df-Na dissolution rates, especially in presence of apple sauce compared to the other food types. Furthermore, storage under long-term and accelerated conditions showed an effect on drug release from pellets.

The stable dibasic tetradentate ligand 1,4-bis-(2-hydroxy-3,5-dimethylbenzyl)piperazine (H2pip-2,4-dmp, I) prepared by reacting 2,4-dimethylphenol with piperazine in the presence of formaldehyde reacts with [MoVIO2(acac)2] and [UVIO2(CH3COO)2] in equimolar ratio to give neutral hexa-coordinated [MoVIO2(pip-2,4-dmp)] (1) and hepta-coordinated [UVIO2(pip-2,4-dmp)(MeOH)] (2), respectively. After characterizing these complexes by spectroscopic (IR, UV/Vis, 1H and 13C NMR) data, elemental and thermal analyses (and single crystal X-ray diffraction study of uranium complex), they are used as catalysts to study the oxidative bromination of thymol. Such catalytic reactions are observed by many model vanadium complexes and are considered as a functional mimic of haloperoxidases. The catalytic oxidation resulted in the formation of three products namely, 2-bromothymol, 4-bromothymol and 2,4-dibromothymol. The optimized reaction conditions are obtained considering concentration of KBr, HClO4, and oxidant for the maximum yield of brominated products. Under the optimized reaction conditions, the product selectivity for both the prepared complexes is investigated. They are found to be competent homogeneous catalysts to afford the products in good yield.

Koksal, Oguz Kagan/0000-0003-2671-6683; Wrobel, Pawel/0000-0002-5445-6201; Apaydin, Gokhan/0000-0002-4647-344X WOS: 000449893000013 Iron, cobalt, copper and zinc decorated hydroxyapatite nanoparticles were produced with using ultrasonically assisted wet chemical method. Calcium nitrate tetra hydrate and dibasic ammonium phosphate were used as calcium and phosphorous source, respectively. Calcium nitrate tetra hydrate and dibasic ammonium phosphate solutions were prepared by dissolving the salts in distilled water and at different concentrations of decorated elements (iron, cobalt, copper and zinc) were appended to the calcium nitrate tetra hydrate solution. Stoichiometric decorated hydroxyapatite nanoparticles were analysed by energy dispersive X-ray fluorescence (EDXRF) with using standard method and the element analysis was determined with looking at the grain structures by Energy Dispersive X-Ray (EDX) and scanning electron microscopy (SEM). Not only have the concentrations of decorated metals but also calcium and phosphorus ratio for artificial bone powders been determined. As a result, calcium and phosphor ratio and metal decorated contents were evaluated according to the production values and compared previous studies. The answer to the question of how much of the contribution amounts was searched.

Mononuclear and binuclear metal complexes of hydrazone oxime resulted from the condensation of acetohydrazide and pyridyl hydrazide with 3-(hydroxyimino) butan-2-one were prepared. All compounds were characterized using elemental, spectral and thermal analyses, as well as magnetic moment and molar conductance measurements. The ligands acted as neutral/monobasic bidentate, monobasic tridentate and dibasic tetradentate ligands bonded to the metal ions via azomethine nitrogen or oxime oxygen atoms and enolic carbonyl oxygen or pyridine nitrogen atom. The spectral and magnetic studies of the complexes showed that exhibit either distorted octahedral, square planer or tetrahedral geometry. Newly complexes were tested for their anti-proliferative activity in vitro against three human cell lines; MCF-7, Hep-G2 and HL-60. The cytotoxic action of the complexes was determined and compared to that of the anticancer drug doxorubicin. Results of cytotoxicity activities indicated that the compound (6) has a wide range of cytotoxicity against the three cell lines in concentration ranges as that of doxorubicin. It shows more cytotoxic against MCF-7 (IC50 = 1.8 μM) and HL-60 (IC50 = 10.6 μM) cancer cell lines. Compounds (H2L1) and (11) exhibited higher cytotoxic activities rather than doxorubicin against MCF-7 and HL-60 cell line. Compounds (2) and (11) are 3.1 and 2.1 times more active than doxorubicin; respectively, against HL-60 cell line. Keywords: Antitumor activity, Hydrazone-oxime, Metal complexes spectral measurements

This analysis highlights the design, spectroscopic characterization and quantum mechanical calculation of some new dioxomolybdenum(VI) complexes of some dibasic tetradentate Schiff bases. Ligands w...

Biodiesel plants are struggling to find value added applications for fatty acid methyl esters (FAME). One option for FAME valorization would be dibasic esters, which can be transesterified with 2-ethylhexyl (2EH) or other alcohols to produce lubricant basestocks and achieve the most widespread viscosity grades VG46 and VG32. Biocatalytic, metathesis and other synthetic pathways are available to produce dibasic esters. Using a ruthenium-based catalyst, methyl oleate was converted into monounsaturated dibasic ester by metathesis and reached VG22 after transesterification with 2EH in this investigation. Synthesized 2EH esters of other dibasic acids showed distinct viscometric trends. Their correlation implied that FAME from gondoic and erucic acids should result in VG32 and VG46 respectively, if converted into 2EH dibasic esters. Pour points demonstrated excellent low temperature fluidity and resistance to heat thinning when monounsaturation was retained. Oxidative stability properties remained acceptable, volatility was lower than that of VG46 mineral oils. Mixed alcohols, acids and esters can also be used for meeting VG specifications or achieving higher biobased contents. Currently petrochemical ester basestocks dominate in high performance hydraulic fluids (HF). However, fractionation of FAME into high-erucic/gondoic esters in biodiesel plants can produce a valuable biobased feedstock for large volume manufacture of HF and other lubricants. This journal is

The composition of Rhodiola rosea L. lipophylic substances was studied. Acidic and neutral components were identified by gas-chromatography-mass-spectrometry. With methyl-tert-butyl ether as an extractant instead of the volatile solvent diethyl ether, lipophylic extract was obtained. Methyl-tert-butyl ether used as an extraction solvent for raw materials has all the advantages of diethyl ether, being free of its disadvantages. It does not form peroxides or produce elevated partial gas pressure due to its higher boiling point. As a result, comparison with databases identified some triterpene and aliphatic acids with chain lengths 12 to 30 carbon atoms, including saturated, unsaturated, and dibasic acids. In addition to the components known from the literature, more than 50 triterpene and aliphatic compounds were detected in the unsaponifiable residue for the first time.

The present study found that sodium phosphate dibasic dodecahydrate (Na2HPO4) was capable of inducing the gelation of thiolated citrus high-methoxyl pectin (TCHMP). TCHMP was synthesized by amidation of citrus high-methoxyl pectin. The gel formation exhibited an obvious concentration-dependence, including TCHMP and Na2HPO4 concentration. For Na2HPO4-induced TCHMP gels (TCHMPGs), gel strength and water holding capacity (WHC) increased, while the microcellular network structure was more compact with the increase of TCHMP and Na2HPO4 concentration. Dynamic viscoelastic experiment showed when Na2HPO4 concentration was more than or equal to 0.5 mol/L, TCHMP sols could be transferred into gels within 30 min. Crystal property was not changed while thermal stability was improved after phase transition. Gelling forces analysis indicated that disulfide bonds were the main interaction forces in TCHMPGs. Consequently, TCHMPGs were covalently crosslinked and exhibited satisfactory gel performance. The results provide a theoretical basis for the formation of gels by Na2HPO4 induced TCHMP.

The template reaction was performed between benzoylacetone-S-propylthiosemicarbazone and salicylaldehyde in the presence of Co(ClO4)2 and a square planar cobalt(II) complex, [Co(L)] (Co1) where L is a dibasic thiosemicarbazidato ligand was isolated. It was aimed to synthesize the octahedral cobalt complexes by using the co-ligands, pyridine and 2-amino pyridine. An octahedral cobalt(III) complex, [Co(L)(py)2]ClO4 (Co2), with two axial-pyridine ligands was obtained. Reaction with 2-amino pyridine gave an unexpected cobalt(III) centered structure, [Co(L1)]·H2O (Co3), where L1 is a new sixdentate (N4O2) ligand that yielded by the addition of the amino group of pyridine to the L ligand. L1 has tribasic thiosemicarbazidato structure that altered by the participation of an oxygen atom in addition to the amines. Experimental characterizations of three complexes have been completed using IR, NMR, UV–Vis, ESI-MS techniques and X-ray data. In order to better understand the intermolecular interactions of the structures, the Nonlinear Optical (NLO) properties and frontier orbitals (FMO) of the complexes were obtained using the Gaussian 09 program, DFT/B3LYP with 6–31 G (d, p) bas set for the C, N, O, H atoms and with LanL2DZ basic set for Co metal atom.