In silico and biological activity evaluation of quercetin-boron hybrid compounds, anti-quorum sensing effect as alternative potential against microbial resistance.

Boronic acid compounds and the natural flavonoid compound quercetin were handled to synthesize two novel ligands encoded as B1(2,2'-(1,4-phenylenebis (benzo [1,3,2] dioxaborole-2,5-diyl)) bis (3,5,7-trihydroxy-4H- chromen-4-one) and B2(3.3.6. 3,5,7-trihydroxy-2-(2-(6-methoxypyridin-3-yl)benzo[d][1,3,2]dioxaborol-5-yl)- 4 H-chromene-4). Antioxidant activities of ligands were investigated by DPPH, ABTS and CUPRAC methods. Cholinesterase inhibition effects of ligands were determined by acetylcholinesterase and butyrylcholinesterase enzyme inhibition methods, cytotoxic effects of ligands were applied to healthy breast and colon cancer cell lines by MTT method, and urease and tyrosinase enzyme activities were determined. Antimicrobial properties of the compounds were analyzed by detecting their anti-QS potentials on Chromobacterium violaceum biosensor strain. Both compounds were found to have significant antioxidant effects compared to controls. It was determined that the compound B1 at 1-10 µg/mL was more active than the reference compounds (α-TOC and BHT). Moreover, the enzyme activity studies on ligands demonstrated that acetylchoinesterase and butyrylcholinesterase enzyme inhibitions were higher than the reference compounds. As expected, boron derivatives exhibited respectable activity against the biofilms of Escherichia coli (E. coli) and P. aeruginosa (P. aeruginosa). These results demonstrate the potential applicability of boron derivatives in the treatment of biofilm-associated infections and provide a practical strategy for the design of new boron-based antimicrobial materials. In silico molecular docking studies were performed on ligands to identify newly synthesized compounds. The binding parameter values and binding sites of the compounds were also determined. In conclusion, our studies showed that newly synthesized hybrid compounds could be solutions for antimicrobial resistance and enzyme-related disorders.

Cream production and biological in vivo/in vitro activity assessment of a novel boron-based compound derived from quercetin and phenyl boronic acid.

Boronic acids constitute an important class of synthetic intermediates due to their high chemical stability, ease of use, moderate organic Lewis acid properties, reduced reactivity profiles and numerous biological activities such as antibacterial and antioxidant. The present study documents the synthesis and characterization of a novel boronic ester compound (3,5,7-trihydroxy-2- (2-phenyl benzo [d] [1,3,2] dioxaborol-5-yl) -4H-chromen-4-a) which was derived from phenyl boronic acid and quercetin. The new boron-based compound was used in the cream formulation after evaluating its antioxidant, antibacterial, anti-enzyme, anticancer activities and electrochemical oxidation behaviour. Furthermore, the cream has been dermatologically and microbiologically tested. Also, histological evaluation of the agent was estimated on multiple rat organs by hematoxylin-eosin staining method. Antioxidant potential of the new compound was tested by ABTS cation radical (IC50: 0.11 ± 0.01 µg/mL), DPPH free radical scavenging (IC50: 0.14 ± 0.01 µg/mL), and CUPRAC (A0.5: 1.73 ± 0.16 µg/mL) methods, respectively. The compound determined to have a dominant antioxidant activity. In addition, the synthesized compound had no toxic effect on the healthy cell line (PDF), while having a very high (IC50: 18.76 ± 0.62 µg/mL) cytotoxic effect on the cancerous cell line (MCF-7). In general, the compound showed moderate acetylcholinesterase enzyme activity (IC50: 115.63 ± 1.16 µg/mL), high butyrylcholinesterase (IC50: 3.12 ± 0.04 µg/mL), antiurease (IC50: 1.10 ± 0.06 µg/mL), and antithyrosinase (IC50: 11.52 ± 0.46 µg/mL) enzyme activities. In addition, the compound was found to be effective against Escherichia coli (ATCC 25922) bacteria studied at concentrations of 6.50 mg/mL. Moreover, the test results of the boronic ester compound used in the cream formulation demonstrated that it was microbiologically and dermatologically appropriate. Histologic analysis showed that the control group and experimental group were at similar properties without significant change. The phenyl boronic acid derivative compound synthesized from quercetin may have higher biological activity potential than quercetin. Due to the high biological activity potential of the synthesized compound, it has the potential to be used in food, feed, pharmaceutical and cosmetic industries.

Development and Validation of a Novel LC-MS/MS Method for the Quantitation of 19 Fingerprint Phytochemicals in Salvia Species: A Chemometric Approach.

Being traditionally utilized mainly as appetizers and herbal teas as well as used to ease abdominal pains, colds and gastrointestinal issues, the genus Salvia L. has gained significant consideration owing to its remarkable phytochemicals and industrial importance. The present study aimed to develop and validate an LC-MS/MS method for the qualitative and quantitative investigation of 19 fingerprint phytochemicals in six endemic Salvia species. The validation parameters of the developed LC-MS/MS method were repeatability (intermediate precision), recovery (accuracy), limits of detection and quantification, linearity and uncertainty (U% at 95% confidence level (k = 2)). Reversed-phase HPLC separation and mass spectrometry parameters were optimized for each analyte. Ethanol extracts of the studied Salvia species collected in three consecutive years were screened for their fingerprint phytochemicals by using the developed and validated LC-MS/MS method. Moreover, studied Salvia species were subjected to multivariate analysis such as principal component analysis techniques to demonstrate the variabilities in phytochemical contents by years and parts of the samples. Roots, flowers, leaves, branches and whole plant of the Salvia species collected in 2015, 2016 and 2017 were used for the analyses. It was observed that the roots and branches of Salvia species were similar in terms of their salvianolic acid A, caffeic acid, and 6,7-dehydroroyleanone components. Accordingly, apigenin, rosmarinic acid, luteolin 7-O-glucoside, caffeic acid, salvianolic acid B, and 6,7-dehydroroyleanone were notable phytochemicals that were present in the studied Salvia species.

Identification of Phenolic Compounds by LC-MS/MS and Evaluation of Bioactive Properties of Two Edible Halophytes: Limonium effusum and L. sinuatum.

This work aimed to evaluate the phenolic content and in vitro antioxidant, antimicrobial and enzyme inhibitory activities of the methanol extracts and their fractions of two edible halophytic Limonium species, L. effusum (LE) and L. sinuatum (LS). The total phenolic content resulted about two-fold higher in the ethyl acetate fraction of LE (522.82 ± 5.67 mg GAE/g extract) than in that of LS (274.87 ± 1.87 mg GAE/g extract). LC-MS/MS analysis indicated that tannic acid was the most abundant phenolic acid in both species (71,439.56 ± 3643.3 µg/g extract in LE and 105,453.5 ± 5328.1 µg/g extract in LS), whereas hyperoside was the most abundant flavonoid (14,006.90 ± 686.1 µg/g extract in LE and 1708.51 ± 83.6 µg/g extract in LS). The antioxidant capacity was evaluated by DPPH and TAC assays, and the stronger antioxidant activity in ethyl acetate fractions was highlighted. Both species were more active against Gram-positive bacteria than Gram negatives and showed considerable growth inhibitions against tested fungi. Interestingly, selective acetylcholinesterase (AChE) activity was observed with LE and LS. Particularly, the water fraction of LS strongly inhibited AChE (IC50 = 0.199 ± 0.009 µg/mL). The ethyl acetate fractions of LE and LS, as well as the n-hexane fraction of LE, exhibited significant antityrosinase activity (IC50 = 245.56 ± 3.6, 295.18 ± 10.57 and 148.27 ± 3.33 µg/mL, respectively). The ethyl acetate fraction and methanol extract of LS also significantly inhibited pancreatic lipase (IC50 = 83.76 ± 4.19 and 162.2 ± 7.29 µg/mL, respectively). Taken together, these findings warrant further investigations to assess the potential of LE and LS as a bioactive source that can be exploited in pharmaceutical, cosmetics and food industries.

A Detailed Chemical and Biological Investigation of Twelve Allium Species from Eastern Anatolia with Chemometric Studies.

Allium species are widely consumed as food all over the world. The phenolic profile of ethanol extracts of aerial parts and roots of 12 Allium species, collected from five different Eastern Anatolia regions, were studied using LC-MS/MS. In vitro antioxidant, anticholinesterase, cytotoxic and antimicrobial activities were also tested. The multivariate analyses were performed using principal component and hierarchical cluster analyses. Seventeen of 27 standard compounds were detected in all Allium species. The major components were mainly identified as quinic acid, malic acid, vanillin, and p-coumaric acid. The aerial parts possessed better antioxidant activity than roots. Aerial parts of A. atroviolaceum, A. chrysantherum, A. kharputense, and A. shirnakiense exhibited high cytotoxic activity against DLD-1 colon cancer cell lines (IC50 12.5 µg/mL). A. shatakiense and A. vineale demonstrated good antimicrobial activity against S. aureus and E. coli (MIC 75 µg/mL). According to chemometric analysis, differences were detected between aerial parts and the roots. The aerial parts of A. atroviolaceum, A. chrysantherum, A. kharputense, and A. shirnakiense could be potent in the pharmaceutical industry while A. shatakiense and A. vineale in the food industry after further investigations.

Parameterization of Boronates Using VFFDT and Paramfit for Molecular Dynamics Simulation.

Boric acid, borate esters, and hydroxy derivatives are biologically active molecules. Thus, performing molecular dynamics simulations of these molecules is vital in terms of drug design, but it is difficult to find directly generated Amber parameters based on an ab initio method for these kinds of molecules in the literature. In this study, Amber parameters for such molecules containing boron were generated based on ab initio calculations using the paramfit program, which applies a combination of genetic and simplex algorithms, and the Visual Force Field Derivation Toolkit (VFFDT) program containing the Seminario method. The minimized structure, after obtaining novel parameters and the sander program, was compared with the experimental crystallographic structures, and it was observed that the root-mean-square deviation (RMSD) value between the experimental structure and minimized structure agreed reasonably well. In addition, the molecule was heated, and the molecular dynamics simulation was successfully obtained with the novel parameters.

Trace Element Analysis by ICP-MS and Chemometric Approach in Some Euphorbia Species: Potential to become a Biomonitor.

In this study, the branch, leaves, flowers, roots and mixed parts of different nine Euphorbia species were analyzed for their trace element contents by using ICP-MS. The samples were digested by concentrated nitric acid and hydrogen peroxide in a microwave by ICP-MS before the analysis. The accuracy and precision of the method was evaluated by CRM 1573a Tomato Leaves. Trace element contents accumulated in different parts of each sample were contrasted. Minitab Statistical Software Inc., programme was used for the multivariate analysis of 12 toxic metals of seeds, roots, branches, leaves, flowers, and mixed parts of Euphorbia species collected from Diyarbakir, Kayseri, Malatya, Mardin, Trabzon, and Van cities.When the studied Euphorbia species are compared in terms of their metal contents; V, Tl, Cr, and Ni metals in E. eriophora, Ba in E. aleppica, As and Co metals in E. segiieriana, Ag and Se metals in E. craspedia, Cu and Cd metals in E. fistulosa, Cs and Pb metals in E. grisophylla, Zn in E. macroclada and also Rb and Sr metals in E. denticulata were determined higher. It was determined that the studied species accumulated some metals at highly amounts especially in the root and leaf parts. In general, it can be said that Euphorbia species have high potential to become a biomonitor. For this reason, it can be predicted that these species will be used as ornamental plants in landscape architecture due to both their toxic metals retention properties and their beautiful appearance.

A comprehensive LC-MS/MS method validation for the quantitative investigation of 37 fingerprint phytochemicals in Achillea species: A detailed examination of A. coarctata and A. monocephala.

The current study aims to optimize and validate a comprehensive LC-MS/MS method for the quantification of 37 phytochemicals (15 phenolic acids, 17 flavonoids, 3 non-phenolic organic acids, 1 phenolic aldehyde and 1 benzopyrene) in Achillea species. Though Achillea species were chosen as real life samples, the current method is applicable to a wide range of plant species. The developed method was fully validated in terms of linearity, accuracy (recovery), inter-day and intra-day precision (repeatability), limits of detection and quantification (LOD/LOQ) and relative standard uncertainty (U% at 95% confidence level (k = 2)). Reversed-phase ultrahigh performance liquid chromatography was optimized to achive optimum separation for 37 phytochemical compounds and to overcome the suppression effects. MS detection was performed using a triple quadrupole mass spectrometer and negative or positive ionization modes were optimized for each analyte. Multiple reaction monitoring (MRM) was used to quantify the analytes, related molecular ions and transition ions were optimized. Phytochemical screening of ethanol and methanol-chloroform extracts of root and aerial parts of A. coarctata and A. monocephala were performed by using the developed and validated LC-MS/MS method. Root and aerial parts of both species have considerable amounts of certain phenolic-nonphenolic acids (quinic, malic, fumaric, chlorogenic and vanillic acids) and flavonoids (rutin, hesperidin, isoquercitrin, apigetrin, luteolin, apigenin). Additionally, total phenolic and flavonoid amounts, antioxidant (DPPH free radical scavenging assay, ABTS radical cation decolorization assay, ß-carotene lipid peroxidation test system and CUPRAC cupper reduction capacity methods), anticholinesterase, tyrosinase, urease inhibition and cytotoxic activities (on HeLa (Human Cervical Carcinoma Cell Line) of A. coarctata and A. monocephala were also investigated. It has been determined that the studied Achillea species, that are rich in total phenolic-flavonoid and chlorogenic acid contents, have high antioxidant and cytotoxic potential at the same time. According to the results of LC-MS/MS, antioxidant and cytotoxic activity studies, after detailed chemical investigation and toxicity studies on these species, A. coarctata and A. monocephala may be promoted as promising sources of natural agents and used for the development of nutraceuticals or functional food ingredients in future.

Ecology and genomics of an important crop wild relative as a prelude to agricultural innovation.

Domesticated species are impacted in unintended ways during domestication and breeding. Changes in the nature and intensity of selection impart genetic drift, reduce diversity, and increase the frequency of deleterious alleles. Such outcomes constrain our ability to expand the cultivation of crops into environments that differ from those under which domestication occurred. We address this need in chickpea, an important pulse legume, by harnessing the diversity of wild crop relatives. We document an extreme domestication-related genetic bottleneck and decipher the genetic history of wild populations. We provide evidence of ancestral adaptations for seed coat color crypsis, estimate the impact of environment on genetic structure and trait values, and demonstrate variation between wild and cultivated accessions for agronomic properties. A resource of genotyped, association mapping progeny functionally links the wild and cultivated gene pools and is an essential resource chickpea for improvement, while our methods inform collection of other wild crop progenitor species.

Elucidation of Phosphodiesterase-1 Inhibitory Effect of Some Selected Natural Polyphenolics Using In Vitro and In Silico Methods.

BACKGROUND: Polyphenols are organic compounds widely found in plants and possess many diverse biological activities. In the current study, eleven polyphenolic compounds [rutin (1), trans-ferulic acid (2), epigallaocatechin gallate (3), fumaric acid (4), chlorogenic acid (5), gallic acid (6), trans-resveratrol (7), propyl gallate (8), (+)-catechin (9), quercetin (10), and kaempferol-3-O-ß-D-galactoside (11)] have been evaluated for their in vitro inhibitory activity against phosphodiesterase- 1 (PDE-1). The active compounds 1, 5, 6, and 7 possessed IC50 values of 173.90 ± 2.58, 36.67 ± 1.60, 325.19 ± 3.62, and 323.81 ± 4.25 µM, respectively. In silico experiments were performed to elucidate the binding patterns of inhibitor molecules with the active sites of the enzymes. RESULT: Molecular docking studies have shown that compounds 1 and 5 have better docking results than standard inhibitor (EDTA) against the PDE-1. In conclusion, chlorogenic acid, rutin, gallic acid, and resveratrol could be promising PDE-1 inhibitors and leads to identify new drug candidates against PDE-1-associated disorders.

The synthesis of boronic-imine structured compounds and identification of their anticancer, antimicrobial and antioxidant activities.

Boronic acid compounds with different substituted groups were handled to synthesize various ligands encoded as B1, B2, B3, B4, B5, B6, B7 and B8. B5 and B7 were tested for the cytotoxic activity against the prostate cancer cells and it was found that the cell viability of cancer cells was decreased while most of the healthy cells could still be viable. 5 µM solutions of B5 and B7 decreased the cell viability to 33% and 44% whereas healthy cells were 71% and 95%, respectively, after treatment. Antimicrobial properties were explored against the bacterial and fungal microorganisms with B1, B5 and B7. The inhibition zones were evaluated for all boronic structures, and the growth inhibition zones were determined in a range of 7-13 mm diameter for different microorganism species. Staphylococcus aureus was the common microorganism that three boronic compounds with imine ligands showed the activity. Antioxidant features of B2, B3, B4, B5, B6, B7 and B8 were investigated by different processes such as Beta-carotene bleaching (BCB), 2,2-diphenyl picryl hydrazyl (DPPH), 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) and CUPric reducing antioxidant capacity (CUPRAC) methods. Significant antioxidant activity was achieved by the phenyl boronic based ligands and these compounds demonstrated as much activity as standards (α-Toc and BHT). In addition, all structures were applied properly without any decomposition during the experiments. They were rather stable both in aqueous media and solid state.

Comparative Studies on Phenolic Composition, Antioxidant, Wound Healing and Cytotoxic Activities of Selected Achillea L. Species Growing in Turkey.

Turkey is one of the most important centers of diversity for the genus Achillea L. in the world. Keeping in mind the immense medicinal importance of phenols, in this study, three species growing in Turkey, A. coarctata Poir. (AC), A. kotschyi Boiss. subsp. kotschyi (AK) and A. lycaonica Boiss. & Heldr. (AL) were evaluated for their phenolic compositions, total phenolic contents (TPC), antioxidant properties, wound healing potencies on NIH-3T3 fibroblasts and cytotoxic effects on MCF-7 human breast cancer cells. Comprehensive LC-MS/MS analysis revealed that AK was distinctively rich in chlorogenic acid, hyperoside, apigenin, hesperidin, rutin, kaempferol and luteolin (2890.6, 987.3, 797.0, 422.5, 188.1, 159.4 and 121.2 µg analyte/g extract, respectively). The findings exhibited a strong correlation between TPC and both free radical scavenging activity and total antioxidant capacity (TAC). Among studied species, the highest TPC (148.00 mg GAE/g extract) and TAC (2.080 UAE), the strongest radical scavenging (EC50 = 32.63 µg/mL), the most prominent wound healing and most abundant cytotoxic activities were observed with AK. The results suggested that AK is a valuable source of flavonoids and chlorogenic acid with important antioxidant, wound healing and cytotoxic activities. These findings warrant further studies to assess the potential of AK as a bioactive source that could be exploited in pharmaceutical, cosmetics and food industries.

Flavonoids from Sideritis Species: Human Monoamine Oxidase (hMAO) Inhibitory Activities, Molecular Docking Studies and Crystal Structure of Xanthomicrol.

The inhibitory effects of flavonoids on monoamine oxidases (MAOs) have attracted great interest since alterations in monoaminergic transmission are reported to be related to neurodegenerative diseases such as Parkinson's and Alzheimer's diseases and psychiatric disorders such as depression and anxiety, thus MAOs may be considered as targets for the treatment of these multi-factorial diseases. In the present study, four Sideritis flavonoids, xanthomicrol (1), isoscutellarein 7-O-[6'''-O-acetyl-ß-D-allopyranosyl-(1→2)]-ß-D-glucopyranoside (2), isoscutellarein 7-O-[6'''-O-acetyl-ß-D-allopyranosyl-(1→2)]-6''-O-acetyl-ß-D-glucopyranoside (3) and salvigenin (4) were docked computationally into the active site of the human monoamine oxidase isoforms (hMAO-A and hMAO-B) and were also investigated for their hMAO inhibitory potencies using recombinant hMAO isoenzymes. The flavonoids inhibited hMAO-A selectively and reversibly in a competitive mode. Salvigenin (4) was found to be the most potent hMAO-A inhibitor, while xanthomicrol (1) appeared as the most selective hMAO-A inhibitor. The computationally obtained results were in good agreement with the corresponding experimental values. In addition, the x-ray structure of xanthomicrol (1) has been shown. The current work warrants further preclinical studies to assess the potential of xanthomicrol (1) and salvigenin (4) as new selective and reversible hMAO-A inhibitors for the treatment of depression and anxiety.

Chemical compositions by using LC-MS/MS and GC-MS and biological activities of Sedum sediforme (Jacq.) Pau.

In this research, the chemical composition and biological activities of various extracts obtained from whole parts of Sedum sediforme (Jacq.) Pau were compared. The amounts of total phenolic and flavonoid components in crude extracts were determined by expression as pyrocatechol and quercetin equivalents, respectively. All of the extracts (petroleum ether, acetone, methanol, and water) obtained from S. sediforme showed strong antioxidant activity in four tested methods. Particularly, the IC50 values of the methanol extract, which was the richest in terms of total phenolic and flavonoid contents, were found to be lower than those of α-tocopherol and BHT in ß-carotene bleaching (9.78 ± 0.06 µg/mL), DPPH free radical scavenging (9.07 ± 0.07 µg/mL), and ABTS cation radical scavenging (5.87 ± 0.03 µg/mL) methods. Furthermore, the methanol extract of S. sediforme showed higher inhibition activity than galanthamine against acetyl- and butyryl-cholinesterase enzymes. Also, acetone and methanol extracts exhibited moderate antimicrobial activity against Candida albicans. The main constituents of fatty acid and essential oil were identified as palmitic acid (C16:0) (28.8%) and α-selinene (20.4%), respectively, by GC-MS. In the methanol extract of S. sediforme, quercetin, rutin, naringenin, and protocatechuic, p-coumaric, caffeic, and chlorogenic acids were detected and quantified by LC-MS/MS. Results of the current study showed that the methanol extract of S. sediforme may also be used as a food supplement.

Preconcentration and determination of copper and cadmium ions with 1,6-bis(2-carboxy aldehyde phenoxy)butane functionalized Amberlite XAD-16 by flame atomic absorption spectrometry.

A new chelating resin, covalently linked 1,6-bis(2-carboxy aldehyde phenoxy)butane with the Amberlite XAD-16 was synthesized and used for preconcentration of Cu(II) and Cd(II) prior to their determination by flame atomic absorption spectrometry (FAAS). It was characterized by elemental analyses and Fourier Transform Infrared Spectroscopy (FT-IR). Cu(II) and Cd(II) ions were quantitatively preconcentrated on minicolumn loaded with synthesised resin at pH 4.00 and 6.00, respectively. They were eluated with 5 mL of 0.5 mol L(-1) HCl. Recoveries of Cu(II) and Cd(II) were found to be 100±2.15, 100±1.40 (N=5), the limits of detection of Cu(II) and Cd(II) in the determination by FAAS (3s, N=20) were found to be 0.33 and 1.19 µg L(-1), respectively. The effect of foreign ions on the recovery has been investigated. The proposed method has been applied for the determination of Cu(II) and Cd(II) ions to the real samples collected from Tigris river water in Diyarbakir and Elazig cities in Turkey. Standard addition method and analysis of the certified reference material (NCS-DC 73350) was employed to check the accuracy of the method.

Prepared and characterization of new macrocyclic Schiff bases and their binuclear copper complexes.

The new five macrocyclic ligands were synthesized by reaction of 2,6-diaminopyridine and various dialdehydes. Then, their copper(II) perchlorate complexes were synthesized by template effect by reaction of 2,6-diaminopyridine, Cu(ClO(4))(2).6H(2)O and aldehydes. The ligands and their complexes have been characterized by elemental analysis, IR, (1)H and (13)C NMR, UV-vis spectra, magnetic susceptibility, conductivity measurements, mass spectra. All complexes are diamagnetic and binuclear. The diamagnetic behaviour of the binuclear complexes may be explained by a very strong anti-ferromagnetic interaction in the Cu-Cu pair.

Synthesis, characterization and structure effects on preconcentration and extraction of N,N'-bis-(salicylaldehydene)-1,4-bis-(p-aminophenoxy) butane towards some divalent cations.

Separation with solvent extraction of Cu(II), Co(II) and Ni(II) from aqueous solution using N,N'-bis-(salicylaldehydene)-1,4-bis-(p-aminophenoxy)butane (H(2)L) as the new extractant has been studied. The new Schiff base, was synthesized by reaction of 1,4-bis-(p-aminophenoxy)butane and salicylaldehyde. Microanalytical data, elemental analysis, UV-vis (1)H NMR and (13)C NMR spectra and IR-spectra were used to confirm the structures. The extractability and selectivity of divalent cations was evaluated as a function of relationship between distribution ratios of the metal and pH or ligand concentration. Cu(+2) showed the highest extractability and selectivity at pH 7.8, whereas Ni(+2) and Co(+2) showed at pH 9.2. From the loaded organic phase, Cu(II), Co(II), Ni(II) stripping were carried out in one stage with aqueous acid solution including various concentrations of HCl. The stripping efficiency was found to be quantitative in case of 1.5M HCl. From quantitative evaluation of the extraction equilibrium data, it has been deduced that the complexes extracted are the simple 1:1 chelates, CuL, CoL, NiL.

Synthesis, characterization and structure effects on extractability and selectivity of N,N'-bis(salicylaldehydene)-1,4-bis-(m-aminophenoxy)butane towards some divalent cations.

The extraction of copper(II), nickel(II) and cobalt(II) from the aqueous phase with N,N'-bis(salicylaldehydene)-1,4-bis-(m-aminophenoxy)butane (MAS), which was synthesized from 1,4-bis(m-aminophenoxy)butane and salicylaldehyde, was studied. Microanalytical data, elemental analysis, UV-visible 1H and 13C n.m.r. spectra and IR-spectra were used to confirm the structures. The extractability and selectivity of divalent cations were evaluated as a function of relationship between distribution ratio of the metal and pH or ligand concentration. Cu+2 showed the highest extractability and selectivity at pH 6.0, whereas Ni+2 and Co+2 showed at pH 9.2. The stoichiometries of the compounds formed were estimated to be CuL, CoL, NiL, where L is N,N'-bis(salicylaldehydene)-1,4-bis-(m-aminophenoxy)butane. It was concluded that MAS can effectively be used in solvent extraction of copper(II), nickel(II) and cobalt(II) from the aqeous phase to the organic phase.