Presence Of Sodium Bicarbonate Research Articles

Overexpression of genes involved in fatty acid biosynthesis increases lipid content in the NaHCO3-tolerant Chlorella sp. JB6.

Fatty acid (FA) contents can be altered in Chlorella JB6 in the presence of sodium bicarbonate (NaHCO3). Overexpression of the FA de novo synthesis genes inhibited the growth of JB6 cells and decreased their resistance to NaHCO3, but these transgenic JB6 strains could grow in a medium containing as high as 300 mM NaHCO3. In JB6, ectopic expression of the FA de novo synthesis genes increased the synthesis of very long-chain saturated FA (> 20C).

Persulfate activation with nitrogen and sulfur co-doped porous biochar to remove thiamethoxam: A combination of radicals and nonradicals

Nitrogen and sulfur co-doped porous biochar (NSBC) was synthesized through the pyrolysis of Phytolacca acinose Roxb biomass in the presence of sodium bicarbonate and L-cysteine monohydrochloride. The resulting NSBC exhibited exceptional adsorption and catalytic degradation properties, demonstrating remarkable efficiency in the oxidation and degradation of thiamethoxam (THM) solutions. To elucidate the underlying oxidation mechanism, a combination of radical quenching techniques and advanced in situ electron paramagnetic resonance (EPR) spectroscopy was employed. The experimental findings revealed that the enhanced oxidation efficiency observed in the NSBC+PS system could be attributed to the synergistic interaction between singlet oxygen (1O2) and Reactive Oxygen Species (ROS). The introduction of nitrogen and sulfur doped facilitated the formation of point defects, which in turn promoted the generation of 1O2. Furthermore, the degradation pathways of THM intermediates were successfully elucidated. This study presents a novel approach for the synthesis and application of high-quality catalysts in water treatment.

Sodium bicarbonate alters protein stability and blood coagulability in a simulated Impella purge gap model.

The Impella® microaxial blood pumps utilize purge fluid containing heparin to prevent biofouling of internal surfaces. Purge fluid interfaces with blood or blood components at two notable internal locations: (1) 5-8μm radial gap ("Radial Gap" or "Gap 1") between the motor shaft and bearing, a site accessible by blood proteins or small molecules; and (2) 100 μm axial gap ("Axial Gap" or "Gap 2") between the impeller rotor and bearing, the site of mixing with larger circulating blood components. Despite its efficacy, heparin in the purge fluid complicates overall patient anticoagulation management. Here, we investigate sodium bicarbonate as an alternative to heparin in the purge fluid in a simulated purge gap micro-environment. To assess protein stability simulated at Gap 1, human serum albumin (HSA; 40 mg/ml) species were quantified utilizing size exclusion liquid chromatography (SEC-HPLC) after stirring with purge fluid (5% dextrose in water (D5W) with heparin (25 U/ml) or sodium bicarbonate (25 or 50 mEq/L)) over a 24-h period. pH measurements were taken immediately prior to stirring. Mixing between blood and purge fluid at Gap 2 was mimicked in vitro utilizing a 60:40 blood: purge fluid ratio. Purge fluid consisted of D5W with or without sodium bicarbonate (25 or 50 mEq/L). Human citrated blood samples were freshly collected with or without the addition of heparin (5U/ml). Coagulability was determined via thromboelastography (TEG). pH measurements of blood mixtures were taken immediately before and after TEG analysis. Sodium bicarbonate alone or synergistically with heparin was effective in increasing protein stability, increasing pH, and reducing coagulability. In the Gap 1 model, sodium bicarbonate led to preservation of HSA monomer after 24h mixing, with monomer composing 88.3 ± 2.3% and 88.6 ± 0.9% of total HSA species for 25 or 50 mEq/L sodium bicarbonate, respectively. Only 60.4 ± 4.3% monomer was observed with D5W alone (p < 0.005). HSA aggregates and fragments were evident in heparin and D5W purge mixtures, but absent in sodium bicarbonate (25 and 50 mEq/L). pH of HSA mixtures significantly increased in the presence of sodium bicarbonate. In the Gap 2 model, combined heparin (5U/ml) and sodium bicarbonate prolonged clotting time (TEG-ACT), leading to an average increase of 795 ± 275 s (p=0.04) and 846 243 s (p=0.03). This trend of reduced coagulability was similarly observed in clot initiation time (R time), clot formation time (K time), and clotting rate (α angle). Blood mixture pH measurements increased with addition of sodium bicarbonate in both heparinized and non-heparinized blood samples. Sodium bicarbonate in the purge fluid has the potential to significantly increase protein stability and reduce protein denaturation at the Impella® radial gap (Gap 1), while reducing blood coagulation at the Impella® axial gap (Gap 2). The influence of sodium bicarbonate on the biochemical environment of the purge fluid may ensure stable purge flow resistance and play a synergistic or supportive role in the purge gap micro-environment when used with systemic anticoagulation.

Isolation, Morphological and Molecular Identification of the Pathogenic and Competitors Fungi Associated with the Edible Mushroom Pleurotus sp. and Control Them

Eleven fungal isolates were isolated from oyster mushroom culture media. 10 isolates showed antagonistic activity against P. pulmonarius, while two fungal isolates did not show any antagonistic activity. the highest pathogenic fungi were identified as T. longibrachiatum, T. pleuroticola, R. arrhizus, M. hiemalis and P. glabrum according to the morphological and molecular methods and were registered in the World Genetic Bank at NCBI with the accession numbers OM438162.1, OM438163.1, OM438161.1, OM453951.1 and OM438160.1, respectively, the species T. pleuroticola, R. arrhizus and M. hiemalis were recorded for the first time in Iraq at the molecular level. The effect of some oils on the growth of the oyster mushroom P. pulmonarius and its pathogenic fungi was studied, the results showed that the highest effect of jojoba oil, olive oil, almond oil, sesame oil and coconut oil at 5% was recorded the highest inhibition of the all tested pathogenic fungi, while no inhibitory effect was recorded for the oyster mushroom P. pulmonarius. Sodium bicarbonate at 3 and 5% showed complete inhibition of the growth of all pathogenic fungi. The results showed that 5% of acetic acid inhibits the pathogenic fungi T. longibrachiatum, R. arrhizus and T. pleuroticola, where the diameters of the colonies reached 2.5, 2.7 and 3.1 cm. respectively. The highest biological efficiency was recorded in P. eryngii growing in the medium treated with the pathogenic fungus P. glabrum in presence of sodium bicarbonate, which reached to 69.58%. In the interaction between oyster mushroom species and the media, the results showed that the highest infection rate was in P. eryngii in the medium treated with T. longibrachiatum, which reached to 39.56%, while the lowest infection rate was with P. pulmonarius grown in the medium treated with sodium bicarbonate and the pathogenic fungus P. glabrum, which was 13.15%. Under the pathogens infection, the highest protein content was found in P. eryngii grown in the treated medium with sodium bicarbonate and P. glabrum resulting in 31.22%, while the lowest protein was12.07%. in P. ostreatus grown in the medium infected with T. longibrachiatum.

Effect of Sludge Residence Time over Anaerobic Biodegradation of High Saline Biomass

Halophytes are unique in that they can thrive in a wide range of soil conditions, from normal to extremely saline. This has recently prompted researchers to consider using halophytes as a phytoremediation end-product as a source for biogas generation. Therefore, applying the anaerobic digestion process for halophytes may have the potential advantage in terms of efficient land utilization, soil remediation, and biogas production. Based on this, the anaerobic digestion efficiency of high saline biomass was investigated in continuous laboratory-scale anaerobic reactors at two different sludge residence times (SRT) of 40 and 80 days. Under mesophilic atmosphere, two reactors were operated, one reactor used organic substrate with 30 g-Na+.L-1 originating from sodium chloride whereas the other was operated with the presence of sodium bicarbonate and sodium sulfate. The salt-tolerant microorganism was gradually developed and the salt concentrations were selected based on the elemental analyses results of 30 species of wild halophyte plants taken from the saline-affected area of the Aral Sea in Uzbekistan during the early phase of the operation. For 40 and 80 days of SRT, respectively, 65.56 percent and 60.42 percent of the feed COD were converted into methane gas by the chloride system. However, only about 60% of the feed COD was converted into methane for bicarbonate, and the remaining fraction of gas was assigned to sulfide as a final product of increased sulfate reduction bacteria activity. These findings showed that the salt-tolerant microorganism could be incubated and the anaerobic digestion process could be adapted for a high-saline substrate, implying that the biodegradability of phytoremediation end-products may be used for methane production.

Andrographolide undergoes modification after illumination by blue laser in the presence of sodium bicarbonate

Andrographolide is the marker compound of Andrographis paniculata (Kalmegh), a herb that constitutes many traditional Asian remedies. In the present photochemical approach to modify its 12-en-14-hydroxyl moiety into 13-enone, a methanol solution of andrographolide has been illuminated with blue laser for 6 hours in the presence of sodium bicarbonate. After the illumination, it has been discovered that the 12-en-14-hydroxyl moiety undergoes modification into the 11-enone.

Unsaturated Polyester Resins and Fiber-Reinforced Polymer Composites from Plant Biomass

We are the first to report the synthesis of maleic acid in quantitative yield by oxidation of 5-hydroxymethyl furfural with hydrogen peroxide in the presence of sodium bicarbonate in an aqueous medium under ambient conditions without the using of toxic catalysts and solvents. 5-hydroxymethyl furfural and 2,5-furandicarboxylic acid have been prepared from hexose plant biomass. Based on maleic anhydride and 2,5-furandicarboxylic acid, unsaturated polyesters were synthesized for the first time from renewable raw materials only. A fiber-reinforced polymer composite based on these polyester resins have been prepared. Strength properties of carbon and glass fiber-reinforced polymer composites are 1.5 times superior to the strength of similar phthalic acid based composites.

Nutrient-dependent morphological variability of Bacteroides thetaiotaomicron.

Unique morphologies can enable bacteria to survive in their native environment. Furthermore, many bacteria change their cell shape to adapt to different environmental conditions. For instance, some bacteria increase their surface area under carbon or nitrogen starvation. Bacteriodes thetaiotaomicron is an abundant human gut species; it efficiently degrades a number of carbohydrates and also supports the growth of other bacteria by breaking down complex polysaccharides. The gut provides a variable environment as nutrient availability is subject to the diet and health of the host, yet how gut bacteria adapt and change their morphologies under different nutrient conditions has not been studied. Here, for the first time, we report an elongated B. thetaiotaomicron morphology under sugar-limited conditions using live-cell imaging; this elongated morphology is enhanced in the presence of sodium bicarbonate. Similarly, we also observed that sodium bicarbonate produces an elongated-length phenotype in another Gram-negative gut bacterium, Escherichia coli. The increase in cell length might provide an adaptive advantage for cells to survive under nutrient-limited conditions.

Synthesis, antimicrobial and antiradical activity of (3-alkoxymethyl-4-hydroxyphenyl)propan-1-ones, intermediates of biologically active compounds and activity comparison with 3-(alkoxymethyl)-4-(alkylamino-2-hydroxypropoxyphenyl)alkanones type of beta blockers

Abstract A homologous series of (3-alkoxymethyl-4-hydroxyphenyl)propan-1-ones was prepared by the reaction of (3-chloromethyl-4-hydroxyphenyl)propan-1-ones with the corresponding alcohols (methanol – decan-1-ol, propan-2-ol, 2-methylpropan-1-ol, 3-methylbutan-1-ol, cyclopentanol, benzylalcohol) in the presence of sodium hydrogen carbonate. The composition of the synthesised compounds was elucidated by IR, UV and 1H-NMR and 13C-NMR spectra. Selected compounds were tested against human pathogens: gram-positive bacterium Staphylococcus aureus (CNCTC Mau 29/58), gram-negative bacterium Escherichia coli (CNCTC 377/79) and yeast Candida albicans (CCM 8186). Their antimicrobial activities were expressed as minimum inhibitory concentrations. Antioxidant activity was determined using DPPH and ABTS.+ methods. It could be shown that both biological activities, antimicrobial and antioxidant, were lower in comparison with the (2RS)-bis [3-(4-acetyl-2-propoxymethyl)phenoxy-2-hydroxypropyl]isopropylammonium fumarate type of beta blockers.

The effects of falsification of meat of slaughtered animals with sodium hydrocarbonate on their quality and safety

State monitoring is carried out to verify compliance with the requirements of the legislation on safety and individual indicators of food quality by market operators who produce meat and meat products, store (wholesale bases) and sell (agro-markets, supermarkets, etc.). When establishing a food hazard, the following conditions are taken into account: the usual conditions of use of the food by the consumer, each stage of its production, processing and circulation; information provided to the consumer, including labeling, including end-of-use (use) information, and other publicly available information on the avoidance of adverse health effects, food-related or food category the possible short- or long-term impact of the food on the health of the person consuming it and on future generations; possible cumulative toxicity effect. Therefore, it is important to develop simple, rapid methods for determining the adulteration of beef, pork, mutton, and meat of goat when carrying out risk-oriented controls on the sale of chilled and chilled meat in agri-food markets under different storage and marketing conditions. The falsification of chilled meat of slaughtered animals with a solution of sodium bicarbonate for 3–4 days of sale at temperatures from 0 to 6 °C was established: in beef and meat of goat – a weakly positive reaction (up to 5%), in pork and mutton positive (5.1% and more). Also falsification of meat of slaughtered animals with a solution of sodium bicarbonate on 17–18 (for beef) and 13–14 days of realization at temperatures from 0 to minus 1 °C was established: in beef, pork and meat of goat – a weak positive reaction (up to 5%), positive in mutton (5.1% or more). The technique of establishing adulteration was based on the use of an alcoholic solution of chrome dark blue with a mass concentration of 0.5%, applied to the surface of the muscle tissue, and after 1–2 seconds, the presence of pale pink color was established – in the absence of meat processing with sodium bicarbonate or from light purple to dark purple in the presence of sodium bicarbonate depending on the amount of meat processed up to 5.0% and 5.1% or more. The results of the studies showed that the stability of the color intensity in the falsification of meat of slaughtered animals by treatment with sodium hydrogen carbonate was 99.9%. The influence of sodium bicarbonate on the quality and safety of meat of slaughtered animals for 3–4 days of realization at temperatures 0–6 °C and 17–18 (for beef) and 13–14 days of realization at temperatures from 0 to minus 1 °C has been established: the content of microorganisms in the superficial layers of muscle tissue decreased significantly (P &lt; 0.01, P &lt; 0.001), and slightly increased slightly in the deep layers (P &lt; 0.05); the pH was significantly (P &lt; 0.001) increased and ranged from 6.45 ± 0.023 to 6.72 ± 0.018; NMAOAM content tended to decrease, but the difference was not significant in the case of a weakly positive reaction (at temperatures of 0–6 °C in beef and meat of goat) and a slight decrease (P &lt; 0.05) in pork and mutton (positive reaction); at temperatures from 0 to minus 1 °C, NMAOAM content tended to decrease, but a significant difference, except for beef (1.10 times, (P &lt; 0.05), was not established: in pork – 1.11 and meat of goat – 1.4 times, where the indicators slightly exceeded the limits of the standards of quality meat (103 CFU/g), respectively – (9.89 ± 2.65) ×102, (10.03 ± 3.62) ×102 and (10.4 ± 2.29) × 102 CFU/g, while in mutton (positive reaction) it decreased significantly by 1.05 times and was within the limits – 9.87 ± 0.27×102 CFU/g.

Spectrophotometric method for designation of nitrobenzene by using o-chloranil so application in Diyala River and waterproof case

A reproducible, critical and simple spectrophotometric method for assay of RNB was investigated is based on (charge transfer complex) formation reaction of RNB with O-Chloranil reagent in the presence of sodium bicarbonate in ethanol to give a highly coloured species with maximal absorption at 440 nm, As well Beer’s law was obeyed in the range of (5-50) µg.mL with a molar absorptivity of 1.21×104 L.mol−1.cm−1 and the limit of detection and quantitation were 0.059 and 0.242 µg.mL respectively. The (average recovery rate) was 101.65% and relative standard deviation (RSD) was better than 0.55%. In addition, it was ratio of 1:1. The method was successfully applied to assay of RNB in Diyala river water and waterproof case.

Bicarbonate and unsaturated fatty acids enhance capsular polysaccharide synthesis gene expression in oral streptococci, Streptococcus anginosus

We recently reported on the capsular polysaccharide (CP) synthesis (cps) genes of the oral streptococci, Streptococcus anginosus. In this study, we investigate the effects of carbon dioxide (CO2), bicarbonate (HCO3-) and unsaturated fatty acids (UFAs) on CP synthesis of S.anginosus. We found that CP production increased when bacteria were exposed to high concentrations of CO2. This increase was similarly observed in the presence of sodium bicarbonate (NaHCO3) under atmospheric condition. Since ectopic expression of carbonic anhydrase, which converts CO2 to HCO3-, eliminated the requirement for CO2 in CP production and growth of S.anginosus lacking this enzyme, it seemed that HCO3- is an essential factor for CP production. Furthermore, UFAs also stimulated the CP production. Promoter-reporter assay and quantitative reverse transcription polymerase chain reaction (RT-qPCR) analysis confirmed that stimulation of CP production occurs at the transcription level. The results of the promoter assays suggest that the expression and stimulation of cps genes by HCO3- or UFAs require the cpsA gene, which is located in the first position of the cps operon. With respect to the relationship between HCO3-and UFAs, HCO3- may stimulate UFA synthesis pathway at transcription level. Therefore, it is possible that UFAs are definitive signals for the CP production in S.anginosus.

Functiaonalization of 2-(1-Cyclohexen-1-yl)aniline Derivatives

The reaction of 2-(1-cyclohexen-1-yl)aniline and -6-methylaniline with phthalic anhydride has afforded 2-(2-cyclohex-1-en-1-ylphenyl)- and 2-(2-cyclohex-1-en-1-ylphenyl)-6-methylphenyl)-1H-isoindole-1,3(2H)-diones. The reaction of the obtained isoindole-1,3-diones with bromine in dichloromethane in the presence of sodium bicarbonate has led to the formation of the product of pseudo-allylic halogenation. Replacement of the halogen atom by methoxy group has been performed by keeping 2-[2-(6-bromocyclohex-1-en-1-ylphenyl)-6-methylphenyl)]-1H-isoindole-1,3(2H)-dione in a methanolic solution in the presence of NaHCO3. The reaction of 2-(2-cyclohex-1-en-1-yl-6-methylphenyl)-1H-isoindole-1,3(2H)-dione with molecular bromine in the presence of methanol has given a co-halogenation product, whereas the dibromination product has been obtained in the presence of octyl alcohol.

Recovery of vanadium from secondary tailing of iron ore by salt roasting-alkaline leaching and solvent extraction processes

In this paper, the recovery of vanadium from the secondary tail deposits of iron ore by salt roasting-alkaline leaching and solvent extraction has been investigated. To extract the vanadium, after the characterizations studies (XRF, SEM, and EPMA analyzes), preliminary leaching was performed using HCl to reduce lime. Subsequently, the solid that was gained from this stage was put in the oven for palletizing and salt roasting (sodium carbonate) at the temperature of 850°C. This sample was leached in the presence of sodium bicarbonate (NaHCO3), under certain conditions. Solvent extraction experiments were carried out on the solution of carbonated leaching under different conditions. According to SEM studies, the dominant are calcium, vanadium, and phosphorus in the sample. The percentage of Vanadium (V), according to EPMA results in the 20 selected points, was determined as 0.65%. XRF analysis showed that V2O5 and CaO contents of sample were 2.04% and 51.72%, respectively. Lime was reduced to 32.59% after initial leaching with HCl. The carbonate leaching resulted in a total recovery of 93.46% at 85 °C for 60 minutes and with 40 g /l of sodium bicarbonate. In addition, under the optimum conditions of pH=6, the ratio Vaq/Vorg=1 and the organic phase concentration of 0.5 M using the anionic Aliquat 336 extractant, Vanadium can be recovered effectively (extraction efficiency=97%) from alkaline leaching solution in the form of decavanadate or and the anions in the form of or in one stage.

Effect of Sodium Chloride Replacement with Potassium Chloride on Quality Traits of Bicarbonate-Marinated Turkey Breast Meat

ABSTRACT This study aims to evaluate the possibility to formulate low-sodium bicarbonate-marinated turkey breast meat. In total, 60 meat cuts (100 × 50 × 30mm) were divided into four treatments: B1 (0.5% sodium bicarbonate and 0% sodium chloride replacement), B2 (0.5% sodium bicarbonate and 15% sodium chloride replacement), B3 (0.5% sodium bicarbonate and 30% sodium chloride replacement), and B4 (0.5% sodium bicarbonate and 45% sodium chloride replacement). The results showed that sodium replacement up to 45% had no impact on texture (as represented by Allo-Kramer shear values) and water activity. After cooking, Group B1 exhibited the highest L* value (72.1) and the lowest b* (6.6) when compared to other groups. In conclusion, replacing sodium chloride with potassium chloride up to 45% in the presence of sodium bicarbonate did not affect negatively several quality traits (sensory traits, composition, and texture, etc.).

Cloning, Expression and Characterization of Two Beta Carbonic Anhydrases from a Newly Isolated CO2 Fixer, Serratia marcescens Wy064.

Bacterial strains from karst landform soil were enriched via chemostat culture in the presence of sodium bicarbonate. Two chemolithotrophic strains were isolated and identified as Serratia marcescens Wy064 and Bacillus sp. Wy065. Both strains could grow using sodium bicarbonate as the sole carbon source. Furthermore, the supplement of the medium with three electron donors (Na2S, NaNO2, and Na2S2O3) improved the growth of both strains. The activities of carbonic anhydrase (CA) and ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO) could be detected in the crude enzyme of strain Wy064, implying that the strain Wy064 might employ Calvin cycle to fix CO2. S. marcescens genome mining revealed four potential CA genes designated CA1-CA4. The proteins encoded by genes CA1-3 were cloned and expressed in Escherichia coli. The purified recombinant enzymes of CA1 and CA3 exhibited CO2 hydration activities, whereas enzyme CA2 was expressed in inclusion bodies. A CO2 hydration assay demonstrated that the specific activity of CA3 was significantly higher than that of CA1. The maximum CO2 hydration activities for CA1 and CA3 were observed at pH 7.5 and 40°C. The activities of CA1 and CA3 were significantly enhanced by several metal ions, especially Zn2+, which resulted in 21.1-fold and 26.1-fold increases of CO2 hydration activities, respectively. The apparent K m and V max for CO2 as substrate were 27mM and 179 WAU/mg for CA1, and 14mM and 247 WAU/mg for CA3, respectively. Structure modeling combined with sequence analysis indicated that CA1 and CA3 should belong to the Type II β-CA.

Efficient approach for regioselective synthesis of new trifluoromethyl-substituted spirotetracyclic isoxazolines and isoxazoles

This paper describes firstly an effective protocol for the synthesis of a new series of five examples of 3-(trifluoromethyl)-3,3a-dihydrospiro[chromeno[4,3-c]isoxazole-4,1′-cycloalkan]-3-ols (4), in which the cycloalkanes — cyclopentane, cyclohexane, cycloheptane, and 4′-methyl- and 4′-t-butyl-cyclohexane — were isolated at yields of 65–84%. The dihydro-isoxazolinols 4 were obtained regioselectively from the reactions of 2,2,2-trifluoro-1-[4-methoxy-spiro(2H-chromen-2,1′-cycloalkane)-3-yl]ethanones (3) with hydroxylamine hydrochloride, in the presence of sodium bicarbonate and methanol as solvent, for 24h at 60°C. The ethanone precursors 3 were synthesized by trifluoroacetylation reaction, employing trifluoroacetic anhydride and mixtures of enolethers and/or acetals derived from spiro[chroman-2,1′-cycloalkan]-4-ones (2) (Kabbe’s adducts), which were obtained beforehand from the reaction of cycloalkanones 1 with 2-hydroxyacetophenone and pyrrolidine. Subsequently, dehydration reactions of isoxazolinols 4, employing thionyl chloride and pyridine, enabled the isolation of another series of five novel spiro-isoxazoles 5 (76–95% yield). The structural features of the two series of new spiro heterocycles (4 and 5) were unequivocally determined with the aid of: one-dimensional 1H, 13C, and 19F NMR spectroscopy; two-dimensional 1H and 13C NMR spectroscopy (NOESY, gHMBC, and gHMQC); single crystal X-ray diffraction; and GC–MS.

Synthesis of Diiodo-Functionalized Benzo[b]furans via Electrophilic Iodocyclization

An electrophilic iodocyclization reaction involving alkynylated 2-iodoanisoles and molecular iodine in the presence of sodium bicarbonate was developed and diiodo-functionalized benzo[b]furans were obtained in yields from 45 to 99%.

Preparation, structure and electrochemistry of heterometallic Ru(II) and Fe(II) complexes

Four ruthenium(II) complexes containing ferrocene-based ligands, Ru(acac)2(dppf) (1), Ru(acac)2(η2-O2CFc) (2), Ru(PPh3)2(η2-O2CFc)2 (3) and Ru(dppf)(η2-O2CFc)2 (4) have been prepared by the reaction of Ru(acac)2(CH3CN)2 with 1,1-bis(diphenylphosphino)ferrocene or Ru(PPh3)3Cl2 with ferrocenecarboxylic acid in the presence of sodium bicarbonate. In these complexes, the Ru center is chelated by the dppf ligand or bound with the ferrocenecarboxylate moiety in a η2 fashion. All the complexes were characterized by microanalyses, 1H and 31P{1H} NMR, ESI-MS, IR, and UV–Vis spectroscopy. The solid state structure of complex 1 was confirmed by X-ray crystallography. Cyclic voltammetry measurements in dichloromethane for all complexes display reversible or quasi-reversible Ru and Fe couples with significant coupling. Two one-electron oxidation waves were observed in the cyclic voltammetry of 3 and 4 due to the stepwise oxidation of [Fe2II,II] into [Fe2II,III]+ and [Fe2II,III]+ into [Fe2III,III]2+.

Click 1,4-regioselective synthesis, characterization, and antimicrobial screening of novel 1,2,3-triazoles tethering fluorinated 1,2,4-triazole and lipophilic side chain

Base-catalyzed alkylation of 5-(4-fluorophenyl)-2,4-dihydro-1,2,4-triazole-3-thione (3) with one or two equivalents of propargyl bromide in presence of triethylamine as catalyst selectively produced the thiopropargylated 1,2,4-triazole 7 in 90 % yield. Under the same reaction conditions, 4-ethyl-5-(4-fluorophenyl)-3-(prop-2-yn-1-ylthio)-1,2,4-triazole (8) was produced. Conversely, when the propargylation was carried out in presence of sodium bicarbonate, a mixture of S,N 4- (24) and S,N 2-bis(propargylated) triazoles (25) was obtained in 85 % overall yield. The click 1,3-dipolar cycloaddition reaction of the mono- (7, 8) and/or bis(propargylated)-1,2,4-triazoles (24) with a variety of long-chain alkyl azides, conducted in t-BuOH:H2O (10:1) in presence of sodium ascorbate and copper(II) sulfate at room temperature, afforded the regioselective 1,4-disubstituted mono- (14–18) and bis(1,2,3-triazole) derivatives (26–30) containing a fluorinated 1,2,4-triazole moiety and a lipophilic side chain. The structures of the new products were elucidated by infrared (IR), 1H and 13C nuclear magnetic resonance (NMR), and mass spectrometry. They were also assessed in vitro for their antimicrobial potency against six bacteria (Bacillus subtilis, Streptococcus pneumonia, Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, and Klebsiella pneumonia) and two fungi (Aspergillus fumigatus and Candida albicans). The bioassay results revealed that some of the tested compounds displayed promising antimicrobial activity.