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ABSTRACTThis study involved the exploration of hydro-distilled essential oil (EsO) from the aerial parts of Cordia dichotoma fruits, stems, seeds and leaves via gas chromatography‒mass spectrometry. Approximately 33 volatile components were detected throughout the study. Almost 27 and 23 compounds (comprising 64.83% and 31.55%, respectively, of the total components) were detected in the fruits and stems, whereas 25 compounds (57.12% of the total components) were detected in the seeds, and 25 compounds (52.48% of the total components) were found in the leaves. The main components of the fruit oil were Nonanal (5.77%), Oleic acid (4.30%), β-Damascenone (4.12%), 3, 4-Dehydro-β-ionone (4.06%), Methyl jasmonate (3.32%), Sabinene (3.31%), Phytol (3.22%) and Vitispirane (3.11%). From stem oil, the major components were Nonanal (6.52%), Nonadecane (3.22%) and 2, 3-Octanedione (2.16%). Whereas, the major components of the seed oils were Nonanal (12.14%), Oleic acid (5.13%), Dihydroactindiolide (3.35%), 2-Methoxy-4-vinylphenol (3.18%), Dodecanoic acid (3.16%) and Methyl jasmonate (3.11%). Similarly, the major components of the leaf oils were 2, 4-di-t-Butylphenol (10.25%), 3-Methylnonane (4.73%), 2-Undecanol (4.64%), 3, 4-Dehydro-β-ionone (3.52%) and Nonanal (3.16%). These EsO were used for antibacterial activity against two bacteria i.e. E. coli (G-ve) and the S. aureus (G+ve) by disc diffusion method to determine the MIC (minimum inhibitory concentration) and MBC (maximum bactericidal concentration). However, among the four parts of C. dichotoma, fruit and seed EsO were highly effective against E. coli (MIC and MBC were 125 μg/mL, 1000 μg/mL respectively) compared to S. aureus (MICs of 250 and 500 μg/mL with an MBC of 1000 μg/mL)

Water pollution caused by the release of organic pollutants is a major environmental concern worldwide. These pollutants can have harmful effects on aquatic ecosystems and the organisms living within them, as well as on human health when contaminated water is consumed. It is essential to implement proper treatment and management strategies to prevent and mitigate water pollution. Moreover, the major untreated industrial effluents are synthetic organic compounds especially 2,4,6-trichlorophenol (TCP) which cause several environmental issues and heath related problems in humans. To cope with this problem, an excellent 2D porous material based on p-DMAC4/GO composite has been synthesized as adsorbent material for the effective removal of 2,4,6-trichlorophenol pollutant from wastewater. In this regard, the advanced analytical tools such as Fourier-Transform infrared (FT-IR), X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM) and Energy-Dispersive X-ray spectroscopy (EDS) were used for its characterization. The results justified the chemical composition, excellent crystalline nature, surface morphology and elemental composition of the synthesized composite material. The synthesized adsorbent material showed 95% adsorption of TCP from wastewater system at optimal conditions i.e., pH (6), adsorbent dosage (30 mg) and shaking time (60 min). The mathematical models such as isotherms, thermodynamics and kinetics studies validate the nature of adsorption process of TCP pollutant. The adsorption data found to be best fitted with Langmuir isotherms (R2 = 0.99); whereas kinetic study suggested the pseudo-second-order nature of reaction with R2 = 0.99. The thermodynamics study confirmed the spontaneous and endothermic nature of the TCP pollutant onto the surface of p-DMAC4/GO material. Moreover, the results of current work were also compared with existing reported adsorbents and data suggested the higher efficiency, feasibility, and reusability of p-DMAC4/GO material to remove the TCP pollutant from the wastewater system.

The objective of this study was to investigate the impact of phytochemical analysis and the antibacterial activity of extracts of stem, flowers and leaves of Tamarix dioica Roxb. ex Roth. Four solvents namely, diethyl ether, ethyl acetate, methanol and acetone were selected to obtain extracts from different parts of the plant. The organic solvent extracts were investigated for phytochemical analysis and antibacterial activity against two bacterial strains, namely Escherichia coli and Staphylococcus aureus. The result of phytochemicals revealed the presence of various constituents, such as phlobatannins, tannins, saponins, alkaloids, phenols, proteins, terpenoids, flavonoids and steroids by using standard procedures. Most of these components were present in methanol and ethyl acetate extract. Therefore, four out of two extracts, such as methanol and ethyl acetate extracts from stems, flowers, and leaves, were used to test their evidence of antibacterial activity. From this, it was observed that the methanol extracts of stem, flowers and leaves of T. dioica were highly effective together with E. coli and S. aureus with a minimum inhibitory concentration (MIC) value of 500 μg/mL. Considering that the ethyl acetate (EA) extracts from the stem, flowers and leaves of T. dioica were examined to be ineffective against E. coli and S. aureus and MIC values were not observed in two strains of bacteria.

The article illustrates about the synthesis of Mn(II)-Morin complex in methanol solvent. The characterization of the complex was carried out using UV-visible, IR, 1H NMR spectroscopic techniques and thermal (i.e. TGA, DSC) techniques. The complex formation was deduced by UV-visible spectra showing the successive Mn-Morin complex formation occurring at 1:1 (metal/ligand) ratio stoichiometrically. The antioxidant capacity of the complex has also been evaluated using 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging method. The work describes that flavonoids complexed with metal ions are more free radical scavengers than the free molecules.

Present study deals with the synthesis of the p-tert-butylcalix[4]arene diamide derivative as ligand (L) and its Fe3+ complex, followed by its characterization using TLC and FT-IR, while UV-Vis and Job’s plot study were performed for complex formation. Antimicrobial activity of the derivative (L) and its metal complex was carried out by the disc diffusion method against bacteria (Escherichia coli and Staphylococcus albus) and fungi (R. stolonifer). Different concentrations of the derivative (L) (6, 3, 1.5, 0.75, and 0.37 μg/mL) and its Fe3+ complex were prepared, and Mueller–Hinton agar was used as the medium for the growth of microorganisms. Six successive dilutions of the derivative (L) and Fe3+ complex were used against microorganisms. Two successive dilutions (6 and 3 μg/mL) of the derivative (L) showed antibacterial action against both Gram-positive and Gram-negative bacteria. In addition, three successive dilutions (6, 3, and 1.5 μg/mL) of the derivative (L) showed antifungal activity. However, all of six dilutions of the Fe3+ complex showed antimicrobial activity. Derivative (L) showed 3 and 1.5 μg/mL minimum inhibitory concentrations (MIC) against bacteria and fungi, respectively. On the contrary, its Fe3+ complex showed 0.37 μg/mL value of MIC against bacteria and fungi. Hence, Fe3+ complex of the derivative (L) was found to be a more effective antimicrobial agent against selected bacteria and fungi than the diamide derivative (L).

In the present study, the esterification of oleic acid with methanol was studied in batch to batch method over hydrothermal carbon catalyst (HTCC) from Ziziphus Mauritiana L. . The synthesized catalyst was characterized by FT-IR, XRD, XPS, SEM, and BET analysis. The surface area and acid density of prepared HTCC were found to be 15.97 m ^2 g ^−1 and 2.53 mmol g ^−1 , respectively. Statistical analysis was performed by using ANOVA, mean, standard deviation and variance method. Statistically there is no significant difference among the means of the 4 variables at the 95% confidence level and the P-value of the F-test is equal to or greater than the 0.05. The maximum oleic acid conversions from methanol were obtained upto 91%. Furthermore, reusability and regeneration study were also carried out to assess to check catalytic performance. The study reveals that HTCC obtained from Ziziphus Mauritiana L. is an excellent catalyst and can be used for esterification of oleic acid to produce biodiesel.

Rutin, one of the excellent chelating agents, has been made to react with Zr4+ and MoO42- ions to get metal complexes in methanol. The synthesis, spectral properties (UV-Vis, 1H NMR, 13C NMR, IR), thermal behavior and antioxidant activity of these complexes have been studied. It has been observed that rutin forms deep yellow colored complexes of mononuclear composition (through 5OH-4CO system in case of Zr4+/catechol site in case of MoO42-) having stoichiometry, 1:2 and 1:1 for Zr4+ and MoO42- ions, respectively. It has been further noticed that these complexes are formed at different pHs, i.e. 4.0 and 8.0 pHs suitable for Zr4+ and MoO42- complexes, respectively. Thermograms also confirm the results of IR and support the presence of water molecules in complexes. Relative antioxidant activity of the rutin ligand, zirconium-rutin and molybdenum-rutin complexes was determined. It was found that both metal complexes have higher antioxidant activity than rutin alone.

The present work deals with the removal of Cr(VI) from aqueous media by modified Amberlite XAD-4 (MAX-4) resin through the solid phase extraction method. Different parameters such as pH, dosage and temperature were optimized during the batch experiment. The experimental data were analyzed by Freundlich, Langmuir, Dubinin-Radushkevich (D-R) and Temkin equilibrium isotherms. Each characteristic parameter of isotherms was determined. The kinetic sorption experiments show that the sorption process follows pseudo second order kinetics. The sorption mechanism was investigated by Reichenberg (R-B) and Morris–Weber equations. From the thermodynamic parameters, it could be concluded that the sorption process is endothermic and spontaneous in nature. The interference and desorption studies were also performed. The results show that MAX-4 resin has the capability to remove Cr(VI) significantly from aqueous media even in the presence of interfering ions.

The present study demonstrates the adsorption of the direct black-38 (DB-38) azo dye on potential and newly synthesized p-tert-butylcalix[6]arene based silica resin (4). Resin 4 was synthesized via the modification of pure silica 1 as 2 followed by the immobilization of p-tert-butylcalix[6]arene (3) onto modified silica (2). It was characterized by using different analytical techniques such as FT-IR, scanning electron microscopy (SEM) and thermo gravimetric analysis (TGA). The effect of adsorbent dosage, pH and the electrolyte effect on the removal of the DB-38 azo dye were evaluated through batch wise adsorption experiments. Maximum adsorption of 91% was achieved at pH 9.0. The textile wastewater samples were used to ensure the field applicability of the newly synthesized adsorbent 4 for the treatment of dye contaminated effluents. All results regarding the removal of the DB-38 azo dye from the aqueous environment prop up resin 4 as an effective adsorbent and it was found that resin 4 has high adsorption efficiency toward the DB-38 azo dye at a wide range of pH as compared to 1 and 2.

This study explores, adsorption efficiency of p-tert-butylcalix[4]arene based modified silica to remove parathion from aqueous environment. The adsorption parameters, i.e. pH, concentration of pesticide solution, contact time and adsorbent dosage were optimized, as 10, 1 mg L-1, 40 min and 0.04 g, respectively. Langmuir, Freundlich and Dubinin-Radushkevich (D-R) isotherm models were used to evaluate the adsorption mechanism. Adsorption constants values of these models suggest that the adsorption of parathion is favorable and were found to be best fit with Freundlich isotherm. From the kinetic study it can be predicted that adsorption of parathion follows Ho and McKay model (pseudo-second order). Thermodynamic parameters, enthalpy (ΔH), entropy (ΔS) and Gibbs free energy (ΔG) have also been evaluated and were found as -132.25, 0.45, -4.14 Jmol-1, respectively.

The study focuses on the interaction between morin and Tin(II) and the resulting complex was characterized through various analytical techniques by comparing it with morin. The complexation was confirmed at first by UV-Vis study, which shows that addition of Tin(II) to morin may produce bathochromic shifts indicative of complex formation. IR spectral studies indicated that carbonyl has involved in coordination with Tin(II). Moreover, 1H-NMR studies validated that in conjunction with carbonyl, 3-OH of morin is more appropriate to be involved in complexation by replacement of its proton. Scavenging activities of morin and its Tin(II) complex on DPPH• radical showed the inhibitory rates of 65% and 49%, respectively. In addition, the reducing capacity of morin was outstanding at 0.5 and 2.0 mg/ml concentrations relative to Tin(II) complex. Overall, the study potentially shows the strong impact in order to design the anticancer drugs jointly from its cytotoxic potential and antioxidant activities, thereby selectively targeting the cancerous cells in result increasing their therapeutic index as well as extra advantages over other anticancer drugs.

The present study explores the copper selective complexation character of 5,11,17,23-tetranitro-25,26,27,28-tetrahydroxycalix[4]arene (p-TNC4) among a series of different alkali, alkaline earth and transition metal ions, i.e. Li+, Na+, K+,Cs+ Mg2+, Ba2+, Hg2+, Cd2+, Pb2+, Co2+ Ni2+ and Zn2+ using absorption spectroscopic technique. p-TNC4 shows pronounced discriminative specificity towards Cu2+ even the interference study of other co-existing ions also proved this selectivity. Furthermore, the solvatochromic effect, effect of acid (acetic acid), alkali (piperidine) on spectra, response time measurement and the stability of p-TNC4-Cu2+ complex in MeCN has also been investigated. The stoichiometric analysis (i.e. Jobs plot) reveals that p-TNC4 forms 1:1 host-guest complex with Cu2+.

The present work demonstrates the comparative extraction efficiency of p-tert-butylcalix[4]arene (1) and its derivatives (2-4) toward a series of some selected reactive dyes such as Reactive Black-5 (RB-5), Reactive Blue-19 (RB-19) and Reactive Red-45 (RR-45). The study elaborates effectiveness of different anchoring groups present on the periphery of calix[4]arene platform and highlights the importance of preorganization concerning the application of supramolecular chemistry in separation science and technology. It has been observed that compound 4 shows good extraction efficiency toward RB-19 among the selected reactive dyes. Enhanced extraction efficiency was observed with the addition of NaCl at pH 7. The proposed extraction mechanism through inclusion complexation was confirmed by log-log plot analysis, which shows 1:1 complexation between 4 and RB-19. The solvatochromic response of 4 in various solvents of different polarities showed good response in methanol. The log K of complex was found as 5.2. The complex formation between 4 and RB-19 has also been confirmed by FT-IR spectroscopy. The recovery of 4 and RB-19 dye was achieved at pH 8 that signifies the reusability of 4 again and again.

The present study deals with the bioactivity assessment of 5,11,17,28-tetrakismorpholinomethyl-25,26,27,28-tetrahydroxycalix[4]arene (3) against a variety of microorganisms including Gram Positive; Staphylococcus albus ATCC 10231, Streptococcus viridans ATCC 12392, Gram Negative: Bacillus procynous ATCC 51189, Enterobacter aerogenes ATCC 13048, Klebsiella aerogenous ATCC 10031, Escherichia coli ATCC 8739, Sallmonella ATCC 6017 and Fungi: Aspergillus Niger ATCC 16404, Aspergillus fumagatus ATCC 90906, Penicillium ATCC 32333. The antimicrobial activity was found by using a modified disc diffusion method. All microorganisms were obtained from the American Type Culture Collection (ATCC) and selective agar media were employed for the growth of microbial strains. Results show that all the tested microorganisms are highly susceptible to compound 3. The MIC of 4 μg/μL and 8 μg/μL was determined against most of the bacterial and fungal strains. The bioactivity of 3 could be a valuable addition in therapeutic index.

The essential oils from leaves and stems of Aerva javanica was extracted through dry steam distillation and the chemical composition of the oil was determined by Gas Chromatography-Mass Spectrometry (GC-MS). Total nineteen compounds were identified, representing 82.96% and 78.92% of the leaves and stems, respectively. The essential oil of Aerva javanica leaves was found to be rich in hentriacontane (21.48%), nonacosane (20.59%), heptacosane (19.78%), pentacosane (5.58%), octacosane (3.47%), triacontane (2.81%) and hexacosane (2.04%). Whereas the essential oil of stems was determined to be rich in nonacosane (23.26%), heptacosane (22.48%), hentriacontane (18.32%), octacosane (3.42%), triacontane (2.24%) and squalene (2.07%). Thirteen chemical constituents were common in the essential oil of both leaves and stems of Aerva javanica.

In this overview, our main aim is to present the design, preparation, characterization, and extraction/sorption properties of chromogenic azocalix[4]arenes (substituted with different groups) toward metal cations. Azocalixarenes, which contain a conjugated chromophore, i.e. azo (-N=N-) group are synthesized in “one-pot” procedures in satisfactory yields. A wide variety of applications is expected by the functionalization of the side arms. Some of them are used to complex with metal ions. These macrocycles due to their bowl-shaped geometry are indeed used as hosts allowing ionic or organic guests to coordinate onto their cavity. The azocalixarene based ionophores are generally applied in various fields such as catalyst recovery, power plant, agriculture, metals finishing, microelectonics, biotechnology processes, rare earths speciation, and potable water purification. Besides these, they find applications in the area of selective ion extractions, receptors, optical devices, chemical sensor devices, the stationary phase for capillary chromatography, ion transport membranes, and luminescence probes etc. This survey is focused to provide overview an of the versatile nature of azocalix[n]arenes as highly efficient extractants for metal ions treated as pollutants.

In this article we have explored the solvatochromic behavior including solvent selection, time study and complexation ability of 5,11,17,23-Tetrakis(N-piperidinomethyl)-25,26,27,28-tetrahydroxycalix[4]arene (3). The complexation behavior of 3 toward the selected transition metals has been explored through FT-IR, UV-visible and fluorescence spectroscopic techniques. It has been found that the ligand 3 has remarkable complexation ability for all selected transition metal (Cd2+, Cu2+, Ni2+, Co2+, Pb2+, Hg2+) ions used in the experiment with exceptionally high affinity for Hg2+ ions. Besides this, by applying method of continuous variation, i.e. Job’s method; the stoichiometric ratio for the complexation between 3 and Hg2+ ion in acetonitrile has been determined, which indicates that 3 forms a 1:1 metal:ligand complex. The strong complexation behavior of 3 for Hg2+ ions was also confirmed by FT-IR and fluorescence spectroscopy. Consequently, it has been deduced that 3 is a versatile compound and can be used in diverse fields such as analytical/environmental chemistry and sensor technology.

Toxic metals (Cd, Hg and Pb) are mostly present in the environment due to natural phenomenon and human activities as well. Exposure of these non-essential elements in the environment causes severe effects. They are known to cause problems in humans as well as in aquatic life. In this work, we demonstrate various studies regarding liquid-liquid extraction of selected ions with different functionalized calixarenes. This review article briefly discusses several molecular designs of calixarenes for divalent ion (Cd2+, Hg2+ and Pb2+) recognition; as well as the relationship between structure and selectivity of the macrocycles is elaborated. The article does not, however, attempt to cover all of the different approaches to these toxic metal ions extraction.

In this article we have explored the extraction efficiency as well as binding ability of calix[8]arene derivative (3) for selected transition metal ions (Co2+, Cd2+, Ni2+, Pb2+ and Cu2+). Picrate salt solutions of these metals were used in the liquid-liquid extraction experiments. It is apparent from the results that ligand 3 shows appreciable high extraction of transition metal cations, with the relative order Pb2+>Cu2+>Ni2+>Co2+>Cd2+ being observed. Highest extraction efficiency has been observed for Pb2+ and Cu2+ i.e. 95 and 91% respectively. The significant extraction and complexation ability for these metal ions may be attributed to the nature, size, structure and geometry of both ligand and metal ions.

Spices and herbs possess antioxidant activity and can be applied for preservation of lipid peroxidation in biological systems. Fenugreek (Trigonella foenum-graecum) is an important spice; its dried seeds have wide application in food and beverages as a flavoring additive as well as in medicines. Crude extracts of fenugreek were prepared by soxhelt extraction method with different solvents such as methanol, ethanol, dichloromethane, acetone, hexane and ethyl acetate. Extracts were subjected for the measurement of total phenolic content (TPC) by Folin-Ciocalteu method as well as flavonoid content, chelating activity, reducing power and antioxidant/radical scavenging activity [1,1-diphenyl-2-picryl-hydrazyl (DPPH°) free radical scavenging activity]. Results from different parameters were in agreement with each other. The results reveal that all extracts of the fenugreek exhibit antioxidant activity. These findings suggest that the fenugreek extracts could act as potent source of antioxidants.

In this article, chromium(VI) extraction properties of two azocalix4arene based receptors (L4 and L6) are reported. A preliminary evaluation of the binding efficiencies of p-substituted azocalix4arene derivatives L4 and L6 was carried out by solvent extraction of Na-dichromate from aqueous solution into dichloromethane at different pH. It was observed that the new compounds are effective extractants for transferring the HCr2O7-/Cr2O72- anions at low pH. The binding ability of these compounds toward HCr2O7-/Cr2O72- anions depends upon Na+ extraction.

The present computational study describes some representative contributions in metal selective sensor development. During the course of study, charge densities have been calculated for a series of methyl (N,N-dimethylamino)phenyl ether and crown ether metal complexes. For the methyl (N,N-dimethylamino)phenyl ether metal complexes the charges on ether oxygen and amine nitrogen have been calculated for both the free methyl (N,N-dimethylamino)phenyl ether and its metal complex. Similar calculations have been carried out for crown ether metal complexes and dimethylamino crown ether metal complexes. The metal ions have been chosen because they cover a wide range of charge densities as well as having strategic significance. Therefore, their extraction, separation, purification and analytical determination are of continuing importance. However, for the crown ether metal complexes the charge on the metal ion and, for the dimethylamino crown ether metal complexes, as well as the charge on metal ion and on the dimethylamino nitrogen in the complex are calculated. The change in charge on the dimethylamino nitrogen after complexation of the ether oxygen(s) is presented and discussed with respect to the combination of a crown receptor and an alkylamine reporter being an effective system for the design of a chemosensor

The complex formation between Cr(III) and morin was carried out in methanol and confirmed by analytical characterization using UV-Vis, IR, 1H NMR, and TG-DTA. UV-Vis shows significant bathochromic shift in benzoyl upon coordination as well as IR well illustrates the peak shift of C=O group and formation of a O–Cr(III) bond. Likewise, 1H NMR studies clarify that Cr(III) metal ion replaces the 5OH proton hence; 5-hydroxy-4-keto site is employed by morin in chelation to form six-membered stable ring system out of three available chelating sites. In addition, TG-DTA denotes the presence of coordinated and crystalline water molecules. The melting point of the complex was found to be 389°C by DSC. In addition, Cr(III)-morin complex was found to be a more potent antioxidant than morin as evaluated by DPPH• and FRAP methods.

The present work describes the synthesis of new 5,11,17,23-tetrakis[(propylthio)methyl]-25,26,27,28-tetrahydroxycalix[4]arene (3) based impregnated resin, its characterization, and sorption behavior for the removal of endosulfan from water. The impregnated resin was characterized through various analytical techniques such as Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), and gravimetric analysis. The sorption efficiency of resin was checked through batch as well as column experiments. Different parameters such as pH, contact time, sorbent dosage, and temperature for the sorption of endosulfan were optimized as 2, 60 min, 3 mg, and 293 K, respectively. Freundlich and Langmuir sorption isotherms were applied to the data to validate the sorption process. The Thomas model was used to calculate the kinetic coefficient (kTH) and maximum sorption capacity (qo) of the resin, which were (3.40 and 3.46) mL·mg–1·min–1as well as (0.338 and 0.318) mg·g–1for α- and β-endosulfan, respectively. Besides this, Lagergren and Morris–Weber equations for kinetic studies show that sorption follows the pseudofirst-order rate equation. The developed sorption method has been applied to polluted surface water samples with a percent removal of 99.5 ± 1 % for both endosulfan isomers. [ABSTRACT FROM AUTHOR]

The article describes the syntheses and extraction properties of a new calixarene based extractant 5, which has been synthesized from 5,11,17,23-tetra- tert-butyl-25,27-bis(chlorocarbonyl-methoxy)-26,28-dihydroxycalix[4]arene ( 4) by treatment with isoniazid (isonicotinic acid hydrazide) in the presence of pyridine. The compound 5 was converted to its methyl iodide salt ( 6) by refluxing 5 with methyl iodide in acetonitrile. In this synthesis it was thought to explore the role of pyridinium sites in the extraction of HCr2O7-/Cr2O72- anions. The complexing properties of 5 toward selected alkali/transition metal cations and HCr2O7-/CrO72- anions are reported. It has been observed that receptor 5 does not extract alkali metal cations but shows an excellent selectivity toward transition metals. The protonated pyridinium form of 5 is an effective form for transferring the HCr2O7-/Cr2O72- anions from an aqueous into a dichloromethane layer. [ABSTRACT FROM AUTHOR]