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A nanosensor, based on 8-hydroxyquinoline functionalized graphene oxide, was developed for the fluorescence detection of Zn2+. It showed high selectivity and sensitivity for Zn2+ion in aqueous solution over other metal ions such as Li+, Na+, Ca2+, Mg2+, Al3+, Cd2+, Co2+, Cu2+, Hg2+, Ni2+, Pb2+, Fe2+, Fe3+and Cr3+. Due to the linearity of the emission intensity toward Zn2+ concentration, fluorescent technique could be used for the detection of Zn2+ ion even at very low concentrations. [ABSTRACT FROM AUTHOR]

The limited clinical efficacy of current symptomatic treatment and minute effect on progression of Alzheimer's disease has shifted the research focus from single targets towards multi-target-directed ligands. Here, a potent selective inhibitor of human butyrylcholinesterase was used as the starting point to develop a new series of multifunctional ligands. A focused library of derivatives was designed and synthesised that showed both butyrylcholinesterase inhibition and good antioxidant activity as determined by the DPPH assay. The crystal structure of compound 11 in complex with butyrylcholinesterase revealed the molecular basis for its low nanomolar inhibition of butyrylcholinesterase ( Ki  = 1.09 ± 0.12 nM). In addition, compounds 8 and 11 show metal-chelating properties, and reduce the redox activity of chelated Cu 2+ ions in a Cu-ascorbate redox system. Compounds 8 and 11 decrease intracellular levels of reactive oxygen species, and are not substrates of the active efflux transport system, as determined in Caco2 cells. Compound 11 also protects neuroblastoma SH-SY5Y cells from toxic Aβ 1–42 species. These data indicate that compounds 8 and 11 are promising multifunctional lead ligands for treatment of Alzheimer's disease. [ABSTRACT FROM AUTHOR]

A series of multitargeted 8-hydroxyquinoline derivatives were designed and synthesized for the treatment of Alzheimer’s disease (AD). In vitro studies indicated that most of the prepared compounds exhibited significant inhibitory effects against self-induced A β 1−42 aggregation and potential antioxidant properties especially compound 5b (IC 50  = 5.64 μM for self-induced A β aggregation; the oxygen radical absorbance capacity using fluorescein (ORAC-FL) value is 2.63 Trolox equivalents). Notably, 5b can chelate biometals and inhibit Cu 2+ /Zn 2+ -induced A β 1−42 aggregation. The cell assays showed that 5b had excellent protective effects against oxidative toxin H 2 O 2 and presented low neurotoxicity in PC12 cells. Furthermore, 5b could penetrate the blood–brain barrier (BBB) in vitro and did not show any acute toxicity in mice at doses up to 2000 mg/kg in vivo . Our findings provide a rationale for the potential application of compound 5b as a lead compound in AD therapy. [ABSTRACT FROM AUTHOR]

The surface modification of porous cellulose acetate (CA) flat sheet membranes containing 8-hydroxyquinoline (as ligand) was carried out by coating with poly(vinyl alcohol) (PVA)/Fe3O4 nanocomposite solution. Nanocomposite solution was provided by in situ formation of Fe3O4 nanostructures in a polymeric solution containing poly(vinyl alcohol) via a facile chemical procedure. The provided membranes were used for Ni(II) and Cd(II) ion removal from aqueous solutions. The influences of membrane modification, initial feed concentration, and filler loading on the membrane performance for removal of the mentioned ions were investigated. The results showed that ion rejection was enhanced by addition of magnetite nanostructures and 8-hydroxyquinoline to the membrane matrix. Several techniques including IR spectroscopy, X-ray diffraction, SEM, water contact angle, and overall porosity measurements were used to characterize the prepared samples. Morphological studies showed appropriate distribution of magnetite nanostructures in the polymeric backbone of nanocomposite membrane. The filtration/regeneration tests were sequentially performed and confirmed the facile regeneration of the nanocomposite membranes. [ABSTRACT FROM AUTHOR]

A flower-like structure responsible for improving the corrosion resistance of AZ31 Mg alloy was successfully obtained by plasma electrolytic oxidation (PEO) followed by post treatment. The PEO coatings samples obtained in electrolytes with/without ZrO 2 underwent to subsequent immersion treatment in 8-hydroxyquinolate (8-HQ) solution for 72 h. It was observed that the formation of flower-like bis (8-hydroxyquinoline) magnesium inside the micro-pores of PEO coating was triggered when the coating was formed from electrolyte without ZrO 2 . As a result, a significant improvement in the corrosion resistance of Mg alloy was obtained. [ABSTRACT FROM AUTHOR]

Investigations have been made on the photophysical behaviour of 8-hydroxy quinoline zinc metal chelate (Znq 2 ) under various environments such as temperature, humidity, UV radiation, acidic and basic solvents and polymer (PMMA: polymethylmetacrylate) matrix in order to explore the effect of these parameters on the photo luminescence (PL) spectra. Znq 2 is solvated in acetic acid and chloroform at different molar concentrations to calculate optical energy band gap as well as to study the shift of π → π* and the n → π* optical transitions in Zn 2+ ions and 8-hydroxy quinoline moieties. When the complex was subjected to annealing, the position of the emission peak remained unaltered at 504 nm with hypochromic shift at higher temperatures. The same has been observed when the complex is subjected to humid environment and UV exposure with no alteration in the emission peak in the former case and 1nm alteration in the later. The excitation and emission spectra of Znq 2 were recorded in basic and acidic solvents at different molar concentrations so as to establish a relation with the obtained absorption spectra. However, the emission peak blue shifted in basic media and red shifted in acidic media with variation in optical density. The PL spectra of molecular doped Znq 2 in PMMA blended films display an emission peak at 499 nm under excitation wavelength of 437 nm. CIE coordinates of Znq 2 were found to be close in all considered environments. These results prove that the emission from the synthesized metal complex can be tuned in the wavelength range of 433–524 nm by selecting the solvent or the polymer according to the requirement, inferring its potential as emissive material for the fabrication of organic light emitting diode (OLED), displays as well as in other optoelectronic applications where green light is essential. [ABSTRACT FROM AUTHOR]

Two novel tetranuclear compounds with general formula of [Ln 4 L 4 (µ 3 -OH) 4 (DMF) x (MeOH) y ] (compound 1 , Ln = Yb, x  = 3, y  = 1; compound 2 , Ln = Tb, x  = 4, y  = 0) were synthesized via simple hydrothermal reaction by using lanthanide nitrate and H 2 L as reactants. The crystal structure of compounds 1 and 2 were in triclinic P  − 1 monoclinic P 2/ c space group, respectively, as evidenced by single crystal X-ray diffraction. Both of them show the coordination features, namely, a distorted tetranuclear lanthanide Ln 4 (OH) 4 cubane core consisting of four µ 3 -OH − bridges, while four H 2 L ligands and four solvent molecules occupy the peripheral part of the cluster. Interestingly, compound 1 exhibits near infrared luminescence upon excitation at 530 nm because of Yb 3+ ion. Furthermore, Compound 1 shows efficient two-photon upconversion property. Magnetic susceptibility measurements indicate that compounds 1 and 2 show an antiferromagnetic interaction between the adjacent Ln 3+ ions. [ABSTRACT FROM AUTHOR]

Selection of a proper inhibitor should be based on the evaluation of its mechanism and effective concentrations. Mechanism of inhibition usually has dynamic character due to changing physicochemical conditions of the environment and corroding metal surface. Most of actually used methods are stationary or contain assumptions which highly influences obtained values. Development of new dynamic method, based on modified EIS, allows excitation of the system by signal composed of galvanodynamic perturbation and AC signal as a set of 20 sinusoids. Such an approach allowed comparison of the obtained results by two simultaneous methods and verification of the selected electric equivalent circuit. Instant value of charge transfer resistance of mild steel exposed to industrial water with changing concentration of 8-Hydroxyquinoline in the system was determined. [ABSTRACT FROM PUBLISHER]

A novel HOQ@MOF-5 compound photocatalyst was successfully constructed by interacting 8- Hydroxyquinoline with MOF-5 synthesized through a room temperature method. The secondary complex formation between the Zn cluster with 8-Hydroxyquinoline harnessed visible light and acted as a mediator to transfer photoinduced electrons to MOF-5 for enhancing the photocatalytic reaction rate with visible light. HOQ@MOF-5 was characterized by various spectroscopic techniques, such as XRD showing the crystalline nature of compound, UV–Visible spectroscopy showing the 2.54 eV band gap of HOQ@MOF-5 and morphological analysis tools, such as the nanoparticle nature of the compound with 9.561 nm particle size. The photocatalytic effect was estimated using the photocatalytic degradation of phenol as a representative organic pollutant under visible light irradiation. This work provides a new compound acting as source of electrons transfer for the development of efficient photocatalysts for remediation of environmental pollution. [ABSTRACT FROM AUTHOR]

A simple and fast dispersive liquid-liquid micro-extraction (DLLME)-spectrofluorimetric technique was developed and validated for the extraction and quantification of trace amounts of Al in fish samples, where 8-hydroxyquinoline was utilized as a spectrofluorimetric probe. In order to optimize the efficacy of the DLLME technique, the impact of experimental parameters on the extraction of Al(III) from fish samples was evaluated. Under the optimal conditions, the method was linear in the concentration range of 0.1-7.0 μg/g (r = 0.9996) with a LOD of 0.092 μg/g; additionally, the method was accurate (RE% of − 3.0 to + 10.0%), precise (RSD% of 1.2-14.3%) and robust (RSD% of 3.8 and p value of 0.21) and its recovery was in the range of 97.0 ± 3.89-110.0 ± 12.5%; moreover, samples were stable before and during the analyses. Therefore, it can be claimed that the developed method could be successfully applied for the quantification of Al in fish samples. [ABSTRACT FROM AUTHOR]

Two new oxovanadium(V) complexes [VOLL1] (1) and [VOLL2] (2) are prepared by the reaction of N′-(2-hydroxybenzylidene)pivalohydrazide (H2L) and [VO(acac)2] (where acac = acetylacetonate) with maltol (HL1) and 8-hydroxyquinoline (HL2), respectively, in methanol. Crystal and molecular structures of the complexes are determined by elemental analysis, infrared and electronic spectra, 1H NMR spectra, and single crystal X-ray diffraction. Complex 1 crystallizes in the monoclinic space group C2/c, with unit cell dimensions a = 15.828(2) Å, b = 22.412(3) Å, c = 12.873(3) Å, β = 121.256(5)°, V = 3903.7(12) Å3, Z = 8, GOOF = 1.036, R1 = 0.0554 and wR2 = 0.1302. Complex 2 crystallizes in the monoclinic space group P21/n, with unit cell dimensions a = 11.995(2) Å, b = 8.700(2) Å, c = 19.466(3) Å, β = 96.497(3)°, V = 2018.3(6) Å3, Z = 4, GOOF = 1.004, R1 = 0.0449 and wR2 = 0.0937. The V atoms are in the octahedral coordination. [ABSTRACT FROM AUTHOR]

The objective of this work is to perform a theoretical analysis of the antioxidant properties of a series of 8-hydroxyquinolines (8-HQs) to rationalize the available experimental results and to design new potent 8-HQ derivatives. The study was carried out in gas phase and in methanol at the DFT/B3LYP/ 6-311++G(d,p) computational level. The formation of stable ArO• radicals is discussed on the basis of different mechanisms, namely, hydrogen atom transfer (HAT), single electron transfer followed by proton transfer (SET-PT), and single proton loss electron transfer (SPLET). The obtained results show that the HAT mechanism is, thermodynamically, more favoured in gas phase, whereas the SPLET pathway is more favoured in polar solvents. The calculated thermochemical descriptors allow classification of the antioxidant power of the studied compounds. [ABSTRACT FROM AUTHOR]

A novel nanosensor based on CdSe quantum dots (QDs) capped with 8-hydroxyqunoline (HQ) was developed for Al3+ ions determination in aqueous solutions. The method is based on the fluorescence enhancement of the HQ functionalized QDs in the presence of Al3+ ions, due to the strong interaction between Al3+ and HQ. Prepared nanosensor exhibited an acceptable selectivity and sensitivity for Al3+ ions in the presence of other metal ions. Plot of Log(I/I0) against Log[Al3+] shows a good linearity in the range of 0.02-3.0 mM, and the method could be used for detection of Al3+ ions concentration in aqueous solutions. [ABSTRACT FROM AUTHOR]

A method for the transition-metal-free direct C-H arylation of unactivated arenes is developed with aryl bromides as substrates and 8-hydroxyquinoline as an efficient promoter. A variety of biaryl compounds with structural diversity are obtained in moderate to high yields. Mechanistic studies reveal that the reaction proceeds via a homolytic aromatic substitution pathway. [ABSTRACT FROM AUTHOR]

Green and blue crystals of the coordination complexes [Cu(8‐hquin)2(H2O)2], 1 and [Cu(pyzca)2(H2O)2], 2 were obtained by the reaction of copper chloride with 8‐hydroxyquinoline (8‐hquinH) or pyrazine‐2‐carboxylic acid (pyzcaH) as ligands. The structures of 1 and 2 were characterized by elemental analyses, electronic absorption, Infrared (IR) and thermal studies. The luminescent behavior complexes 1 and 2 was also discussed. The coordination environment of copper(II) center displays distorted octahedral coordination geometry. The structure of the complexes 1 and 2 is constructed by an infinite number of discrete mononuclear molecules extending along the a‐axis to form a 1D‐chain via H‐bonds. The extensive hydrogen bonds and short contacts develop the structures of 1 and 2 to 3D‐network. The catalytic behavior of the complexes 1 and 2 was utilized for degradation of methylene blue dye (MB). The kinetic data indicated that the complexes 1 and 2 are effective catalysts for degradation of MB dye. Photoluminescence probing technology was used as a sensitive probe for detecting •OH radicals. [ABSTRACT FROM AUTHOR]

A new amphiphilic probe Q-16 bearing a hydroxylquinoline ring and a long hydrophobic cetyl chain has been synthesized and characterized. In aqueous solution, this probe can self-assemble fluorescent nano-structure aggregation, which is confirmed by the tyndall scattering experiment, dynamic light scattering (DLS) and transmission electron microscopy (TEM) techniques. Upon the addition of Hg 2+ , this probe shows a fluorescence quenching effect without interference from other metal ions. The detection limit of Q-16 to Hg 2+ is 4.42 nM. 1 H NMR titrations and DFT calculation results reveal that the triazole ring, the quinoline ring and the ether O atom of Q-16 play an important role for binding with the Hg 2+ center. However, probe Q-16 shows sensing of Hg 2+ , Cd 2+ , Ni 2+ , Cu 2+ and Al 3+ in CH 3 CN solution. Importantly, sensitivity and selectivity of Q-16 toward Hg 2+ in aqueous solution is higher than that in CH 3 CN solution for aggregation. [ABSTRACT FROM AUTHOR]

8-Hydroxyquinoline (8-HQ) was used for modification of Fe3O4 nanoparticles (NPs) and preparation of polyethersulfone (PES)-based mixed matrix membranes (MMMs) by phase inversion process. The synthesized nanoparticles were characterized by Fourier transform infrared spectroscopy (FTIR), Energy dispersive x-ray spectroscopy (EDX), and Field emission scanning electron microscopy (FESEM). The effect of different concentrations of 8-HQ/Fe3O4 NPs into the PES as membrane matrix was investigated by FESEM and atomic force microscopy (AFM). The performance of prepared membranes was evaluated by the water contact angle, pure water flux (PWF), porosity, means pore size, and salt rejection. Bovine serum albumin (BSA) solution was used to investigate the antifouling properties of fabricated membranes. The results showed a decreasing water contact angle from 68.1° for the pristine membrane to 38.3° for M5 at 0.5 wt% 8-HQ/Fe3O4 NPs. The PWF enhanced for all mixed matrix membranes compared with the pristine membrane. The highest PWF (21.5L/m2h) was measured for M4 at 0.2wt% NPs, Wwhile it was 7.1 L/m2h for pristine membrane. Salt rejection improved from 58.55% in M1 (pristine membrane) to 96% in M4 (at 0.2 wt% of 8-HQ/Fe3O4 NPs). Also, the modified membranes showed suitable antifouling property. [ABSTRACT FROM AUTHOR]

Luminescent silver nanoclusters (NCs) decorated with temperature-responsive copolymer P(NIPAm-co-MQ) have been fabricated in aqueous solution as a new fluorescent pH stimuli-responsive functional materials. P(NIPAm-co-MQ) was prepared by a conventional free-radical copolymerization of isopropylacrylamide (NIPAm) as thermo-responsive units and 5-(2-methacryloylethyloxymethyl)-8-quinolinol (MQ) as coordinating groups. The obtained fluorescent Ag NCs with various sizes showed different morphologies from single sphere to chain structure induced by the copolymer ligand. Upon changing the temperature, the fluorescence intensity of the Ag NCs exhibited temperature triggered response simultaneously. The copolymer stabilized Ag NCs as a pH probe exhibited reversible pH-dependent PL properties over the pH range of 3.04–5.25. With the pH decreased, the fluorescence intensity of Ag NCs under a UV lamp decreased and it was almost completely quenched after pH 3.04. Also, the properties of this fluorescence change with pH are reversible. [ABSTRACT FROM AUTHOR]

In the present investigation, three 5-amino-8-hydroxyquinolines derivatives namely, 5-aminomethyl-8-hydroxyquinoline (AMHQ), 5- N -acethylaminomethyl-8-hydroxyquinoline (ACAMHQ), 5- N , N ′-dimethylaminomethyl-8-hydroxyquinoline (DMHQ) were prepared and characterized by IR, 1 H NMR, 13 C NMR, Elemental analysis and Mass spectrometry. These three 5-amino-8-hydroxyquinolines derivatives were tested in the inhibition of corrosion of carbon steel (CS) in 1 M HCl using electrochemical impedance spectroscopy (EIS), Tafel polarization, weight loss, scanning electronic microscopy (SEM) and UV–visible spectroscopy. It was found that the inhibition efficiency of AMHQ, ACAMHQ and DMHQ increased with increasing concentration. For the three organic compounds, the DMHQ shows better efficiency than the other two products reaches 97% at 10 − 3 M concentration. Polarization studies showed that AMHQ, ACAMHQ and DMHQ inhibitors were of mixed type in nature. The experimental data maked from EIS method show a frequency distribution and therefore a modeling element with frequency dispersion behavior, a constant phase element (CPE) has been utilized. To determine certain thermodynamic parameters of activation, the effect of temperature on corrosion rate was studied. The adsorption of 5-substituted-8-hydroxyquinolines derivatives on the carbon steel (CS) surface followed Langmuir adsorption isotherm. Scanning electron microscopy (SEM) and UV–visible spectroscopy were carried out on inhibited and uninhibited carbon steel samples to characterize the surface. Theoretical calculations were performed to gain further insight into the interaction of the inhibitors with carbon steel. [ABSTRACT FROM AUTHOR]

A novel colorimetric chemosensor based on push-pull dye (8HQA) was synthesized and characterized by using IR, 1 H/ 13 C NMR and HRMS for the purpose of recognition of anions and cations in DMSO. The absorption maxima of the chemosensor were determined in different solvents. The selectivity and sensitivity of 8HQA to anions were determined with spectrophotometric and 1 H NMR titration techniques. The selectivity of 8HQA for studied anions (CN − , F − , Cl − , I − , AcO − , HSO 4 − and H 2 PO 4 − ) was determined in DMSO. There is no selectivity between competing anions such as CN − , F − AcO − and H 2 PO 4 − at the stoichiometric ratio of 1:1 in UV-vis titrations experiments however, it was observed different color changes upon addition of CN − , F − , AcO − and H 2 PO 4 − to the DMSO solution. In addition, the chemosensor showed no colorimetric response for the following anions; Cl − , I − and HSO 4 − in DMSO. The colorimetric sensing ability of 8HQA was studied in the presence of chloride salts of different cations such as Ca 2+ , Mg 2+ , Cu 2+ , Co 2+ , Sn 2+ , Ni 2+ , Cd 2+ and Hg 2+ . Upon the addition of 4 equiv of each of the cations showed bathochromic shifts except for Ca 2+ and Cu 2+ . Interestingly, no selectivity was observed in interaction with metal cations. In addition, the molecular and electronic structures of 8HQA, as well as the molecular complexes of 8HQA, formed with the anions, were obtained theoretically and confirmed by DFT and TD-DFT calculations. [ABSTRACT FROM AUTHOR]

In this study, phthalonitriles 6, 7 and their corresponding bromo derivatives 8, 9 were synthesized from 8- hydroxyquinoline to investigate antiproliferative and cytotoxic activities on C6 (rat brain tumor), HeLa (human cervix carcinoma) and HT29 (human colon carcinoma) cancer cell lines of these molecules. The antiproliferative and apoptotic effects of 7-bromo- and 5,7-dibromo-8-hydroxyquinoline derivatives (2 and 3) and phthalonitrile 6, 7 and their brominated derivatives 8, 9 were compared in terms of Structure Activity Relationship (SAR). Although bromohydroxyquinoline derivatives 2 and 3 exhibited high antiproliferative activity according to literature, it has been determined that phthalonitrile compounds 6, 7 and their brominated 8, 9 derivatives are significantly reduced in antiproliferative activity. The SAR of the quinoline core at C-8 revealed that OH group lead to antiproliferative and apoptotic activity. In addition, biological activity was decreased when alkyl or substituted cyclic groups bounded to OH of quinoline, and the bromination of these derivatives did not increase the antiproliferative activity. [ABSTRACT FROM AUTHOR]

Insensitivity to platinum, either through inherent or acquired resistance, is a major clinical problem in the treatment of many solid tumors. Here, we explored the therapeutic potential of diethyldithiocarbamate (DDC), pyrithione (Pyr), plumbagin (Plum), 8-hydroxyquinoline (8-HQ), clioquinol (CQ) copper complexes in a panel of cancer cell lines that differ in their sensitivity to platins (cisplatin/carboplatin) using a high-content imaging system. Our data suggest that the copper complexes were effective against both platinum sensitive (IC ~ 1 μM platinum) and insensitive (IC > 5 μM platinum) cell lines. Furthermore, copper complexes of DDC, Pyr and 8-HQ had greater therapeutic activity compared to the copper-free ligands in all cell lines; whereas the copper-dependent activities of Plum and CQ were cell-line specific. Four of the copper complexes (Cu(DDC), Cu(Pyr), Cu(Plum) and Cu(8-HQ)) showed IC values less than that of cisplatin in all tested cell lines. The complex copper DDC (Cu(DDC)) was selected for in vivo evaluation due to its low nano-molar range activity in vitro and the availability of an injectable liposomal formulation. Liposomal (Cu(DDC)) was tested in a fast-growing platinum-resistant A2780-CP ovarian xenograft model and was found to achieve a statistically significant reduction (50%; p < 0.05) in tumour size. This work supports the potential use of copper-based therapeutics to treat cancers that are insensitive to platinum drugs. [ABSTRACT FROM AUTHOR]

Co-precipitation procedure has widely been employed for preconcentration and separation of metal ions from the matrices of environmental samples. This is simply due to its simplicity, low consumption of separating solvent and short duration for analysis. Various organic ligands have been used for this purpose. However, there is dearth of information on the application of 8-hydroxyquinoline (8-HQ) as ligand and Cu(II) as carrier element. The use of Cu(II) is desirable because there is no contamination and background adsorption interference. Therefore, the objective of this study was to use 8-HQ in the presence of Cu(II) for coprecipitation of Cd(II), Co(II), Cr(III), Ni(II) and Pb(II) from standard solutions and surface water prior to their determinations by flame atomic absorption spectrometry (FAAS). The effects of pH, sample volume, amount of 8-HQ and Cu(II) and interfering ions on the recoveries of metal ions from standard solutions were monitored using FAAS. The water samples were treated with 8-HQ under the optimum experimental conditions and metal concentrations were determined by FAAS. The metal concentrations in water samples not treated with 8-HQ were also determined. The optimum recovery values for metal ions were higher than 85.0%. The concentrations (mg/L) of Co(II), Ni(II), Cr(III), and Pb(II) in water samples treated with 8-HQ were 0.014 ± 0.002, 0.03 ± 0.01, 0.04 ± 0.02 and 0.05 ± 0.02, respectively. These concentrations and those obtained without coprecipitation technique were significantly different. Coprecipitation procedure using 8-HQ as ligand and Cu(II) as carrier element enhanced the preconcentration and separation of metal ions from the matrix of water sample. [ABSTRACT FROM AUTHOR]

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Two new oxidovanadium(V) complexes, [VO(L)(L)] ( I) and [VO(L)(L)] ( II), where L and L are the dianionic form of N'-(2-hydroxy-5-methoxybenzylidene)pivalohydrazide (HL) and N'-(2-hydroxy-3-methoxybenzylidene)pivalohydrazide (HL), respectively, and L is the monoanionic form of 8-hydroxyquinoline (HL), were prepared and characterized by elemental analysis, infrared and electronic spectra, and H NMR spectra. Structures of the complexes were further confirmed by single crystal X-ray determination (CIF files CCDC nos. 1477854 ( I), 1477856 ( II)). HL and HL coordinate to the V atoms through the phenolate O, imino N, and enolate O atoms. 8-Hydroxyquinoline coordinates to the V atoms through bidentate ON donor set. The V atoms of the complexes are in octahedral coordination with the oxo group furnished the octahedral geometry. The complexes show effective antibacterial activity against Bacillus subtilis. [ABSTRACT FROM AUTHOR]

Acombined chemical and instrumental approach is proposed for improving the metrological characteristics of drug determinations in pharmaceutical preparations covering the classes antibiotics, antioxidants, antiseptics, and anesthetics. Simple and accessible colorimetric and indirect x-ray fluorescence methods for determining 8-hydroxyquinoline, novocaine, quercetin, and tetracycline in pharmaceuticals using chemically modified polyurethane foam absorbents were developed based on this approach. The developed approach could be used to determine active ingredients for preliminary quality control of drugs. [ABSTRACT FROM AUTHOR]

The mechanism models of PPNC directly interacting with responsive ions. Cu2+, Ni2+, Pd2+ show excellent quenching effect on Poly[9-(1,10-phenanthroline-2-yl)-9H-carbazol-3-amine] (PPNC). This graph vividly describes the process of fluorescence changing after adding these ions, and the mechanism model is given according to the binding ratio calculated by the Job's plot curves and the results of theoretical calculation. [Display omitted] • Two new types of Poly(3-amino-carbazole) derivatives were synthesized. • 1,10-phenanthroline and 8-hydroxyquinoline ligands were creatively introduced into side chains as functional groups. • PPNC exhibits excellent selectivity and sensitivity for detecting Ni2+, Cu2+, Pd2+. • The response of metal ions to PPNC can be expressed by visual test paper instantaneously. As we know, excessive metal ions can even damage human health. Herein, two novel kinds of fluorescent sensing materials Poly(3-amino-carbazole) derivatives containing 1,10-phenanthroline and 8-hydroxyquinoline were synthesized and further applied to fluorescence detection for ions. The results show that Ni2+, Cu2+, and Pd2+ have excellent quenching effects on the fluorescence of Poly[9-(1,10-phenanthroline-2-yl)-9H-carbazol-3-amine] (PPNC), the LOD for these ions reaches 5.2 nM, 12.7 nM, 33.5 nM respectively. In the process of ion response, there is no shift of UV absorption peak, combined with IR spectra and theoretical calculation simulation, the quenching is considered to be caused by the coordination between metal ions and the second amine (–NH-) or 1,10-phenanthroline ligand of PPNC, which leads to the charge transfer from ligands to metal ions. In addition, an acid test was done for PPNC to verify and detect the presence of secondary amine (–NH-), and the results show that PPNC has good acid sensing ability which also supports the secondary amine (–NH-) structure. Finally, the paper test was performed on PPNC, indicating that PPNC has the potential for visual application. [ABSTRACT FROM AUTHOR]

8-hydroxyquinoline coordinated zirconium(IV) complexes exhibit good aqueous solubility and stability, the cytotoxicity of them were significantly enhanced against human Hela S3, Hep G2 and PC9 cells than cisplatin but limited against normal AML12 cells. [Display omitted] • 8-hydroxyquinoline Zr(IV) complexes exhibit excellent aqueous stability and solubility. • One Zr(IV) complex showed significantly enhanced activity against Hep G2 cells than cisplatin. • These Zr(IV) complexes could almost exclusively induce the cell apoptosis of Hep G2 cells. Three octacoordinated zirconium(IV) tetrakis -(8-hydroxyquinolinate) complexes [(L 1-3) 4 Zr(IV)] were synthesized smoothly in THF at room temperature using ZrCl 4 as a starting material with yields ranging from 74% to 83%. Their structures were characterized by 1H, 13C NMR and X-ray diffraction spectroscopy. [(L 1-3) 4 Zr(IV)] exhibited excellent solubility and stability in H 2 O and DMSO, and they have demonstrated enhanced cytotoxicity against human Hep G2, Hela S3 and PC9 cells than cisplatin. Among them, [(L 1) 4 Zr(IV)] bearing non-substituted 8-hydroxyquinoline showed about 2 orders of magnitude higher inhibition activity against Hep G2 cells than cisplatin (IC 50 : 0.14 ± 0.1 μM, cisplatin: 13.82 ± 1.3 μM). The selectivity towards tumor cells was preliminary evidenced by their partial or completely vanished inhibition activity against AML12 cells. Additionally, [(L 1) 4 Zr(IV)] could almost exclusively induce the apoptosis of Hep G2 cells. [ABSTRACT FROM AUTHOR]

[Display omitted] • A polydentate 8-hydroxyquinoline ligand with a sym -triazine core. • Porous coordination polymer is synthesized via solid–liquid interface reaction. • The strongly polar triazine cores induce interchain excited states. A polydentate 8-hydroxyquinoline ligand with a triazine core has been synthesized via aryl nitrile trimerization, which chelates Zn2+ ions at ice surface to form porous coordination polymer via interface reaction. The porous coordination polymer in organic solvent shows a photoluminescence (PL) spectrum with a peak at 610 nm, while a red-shifted PL peak at 675 nm and a new PL shoulder peak at 770 nm appear in the PL spectrum of the porous coordination polymer film. The 770 nm emssion is inferred from the interchain excited state due to the strong interchain interaction caused by the polar triazine core. [ABSTRACT FROM AUTHOR]

• Compounds [Cr(GLU)(HQ)] (1) and [Cr(FRU)(HQ)] (2) were synthesized. • Complexes were characterized by FT-IR, UV-Vis, Mass spectrometry X-ray Powder diffraction (XRD), and CHN analysis. • The theoretical geometries determined on the basis of the physicochemical and computational investigations mentioned were in excellent agreement with earlier works. • Density functional theory (DFT) analysis was used to examine these complexes' geometric characteristics, HOMO and LUMO. • Powder X-ray diffraction (PXRD) patterns were successfully indexed according to an orthorhombic structure with the space group Pmmm. • Square planar geometry is proposed for Cr (III) complex in case [Cr(FRU)(HQ)] (2), whereas complexes [Cr(GLU)(HQ)] (1) showed tetrahedron coordination around the metal ion. • The destabilizing Pauli term (EPauli) for the glucose complex (1) is calculated to be significantly lower than for the fructose (2) analogous (350.6 vs. 364.8 kcal/mol). • The studied complexes represent efficient antibacterial agents and showed high activity against most types of bacteria. The current study reports on combined experimental and computational studies on chromium (III) complexes' molecular structure and spectroscopic assignments. Complexes of the general formulas [Cr (GLU) (HQ)] (1), [Cr (FRU) (QH)] (2), (where (GLU) is Glucose, (FRU) is Fructose, and (HQ) is 8-Hydroxyquinoline) were synthesized in two steps. Beginning with the reaction of [Cr(C 5 H 7 O 2) 3. nH 2 O] with GLU or FRU, followed by the addition of HQ as co-ligand. Initial characterization based on elemental and mass analyses has suggested possible structures of 1 and 2. In the suggested structures, the GLU or FRU and (8-HQ) ligands are bonded to the Cr(III) metal center. The information of powder X-ray diffraction (XRD) structure suggested molecular structures. Other spectroscopic properties of the complexes were examined by UV-Vis techniques. The detailed vibrational assignment which has been done for the observed FT-IR spectrum in solid-state was observed in the region of 4000–600 cm−1. Density Functional Theory (DFT) calculations were carried out to investigate the geometry of the coordination complex using the Amsterdam Molecular Simulation AMS2022.101 release code (vide supra) and Gaussian 09 program. The molecule geometry was optimized using Density Functional Theory with B3LYP functional and Triple-zeta (TZP) basis sets, in the ground state. The Highest Occupied Molecular Orbital (HOMO) and the Lowest Unoccupied Molecular Orbital (LUMO) were calculated using the DFT/B3LYP method with the SDD basis sets in the ground state. From the optimized geometry of the molecule, geometric parameters (bond lengths and bond angles) and vibrational assignments of the compounds have been calculated theoretically. Moreover, the new complexes were tested against the selected species of antibacterial types: Staphylococcus aureus (ve), Pseudomonas aeruginosa (-ve), Escherichia coli (-ve), and also against Candida albicans and Aspergillus flavus. The results revealed that the new compounds showed good efficacy at high concentrations toward the growth inhibition of the selected pathogenic microorganisms. [ABSTRACT FROM AUTHOR]

[Display omitted] • Thirteen novel 8-hydroxyquinoline-chalcone hybrids were designed and synthesized. • 3d, 3e, 3f, 3i, 3k, and 3l showed effective inhibition against HCT116 and MCF7 cancer cell lines a dual Tubulin/EGFR kinase in-vitro inhibition. • 3e & 3f were subjected to cell cycle analysis, apoptosis assay, RT-PCR of wnt1/β-catenin gene expression assay. • Western plotting for apoptosis markers Bax, bcl2, casp3, casp9, PARP1, and β-actin. • Molecular docking for 3d, 3e, 3f, 3i, and 3l against 3D crystal structures of tubulin and EGFR. The present study established thirteen novel 8-hydroxyquinoline/chalcone hybrids 3a–m of hopeful anticancer activity. According to NCI screening and MTT assay results, compounds 3d- 3f, 3i, 3k, and 3l displayed potent growth inhibition on HCT116 and MCF7 cells compared to Staurosporine. Among these compounds, 3e and 3f showed outstanding superior activity against HCT116 and MCF7 cells and better safety toward normal WI-38 cells than Staurosporine. The enzymatic assay revealed that 3e, 3d, and 3i had good tubulin polymerization inhibition (IC 50 = 5.3, 8.6, and 8.05 µM, respectively) compared to the reference Combretastatin A4 (IC 50 = 2.15 µM). Moreover, 3e, 3l, and 3f exhibited EGFR inhibition (IC 50 = 0.097, 0.154, and 0.334 µM, respectively) compared to Erlotinib (IC 50 = 0.056 µM). Compounds 3e and 3f were investigated for their effects on the cell cycle, apoptosis induction, and wnt1/β-catenin gene suppression. The apoptosis markers Bax, Bcl2, Casp3, Casp9, PARP1, and β-actin were detected by Western blot. In-silico molecular docking, physicochemical, and pharmacokinetic studies were implemented for the validation of dual mechanisms and other bioavailability standards. Hence, Compounds 3e and 3f are promising antiproliferative leads with tubulin polymerization and EGFR kinase inhibition. [ABSTRACT FROM AUTHOR]

The inhibition effect of 8-hydroxyquinoline (8-HQ) on the corrosion of gray cast iron rotors for automotive applications was studied by potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) in a 0.1 M HCl solution. The experimental results suggest that the 8-hydroxyquinoline is a mixed inhibitor reducing both the anodic and the cathodic current densities. Besides, EIS results indicate that the inhibitor provides a stable protection over 9 days of exposure to the electrolyte due to the cooperative formation of an adsorbed layer of 8-HQ on the rotor and a top layer probably constituted by a complex between 8-HQ and iron. The presence of the adsorbed layer and the complex with 8-HQ was confirmed by means of Energy Dispersive X-ray analysis (EDX) and Fourier-transform spectroscopy (FT-IR). [ABSTRACT FROM AUTHOR]

A newly synthesized ligand, 5-((1H-indol-1-yl)methyl)quinolin-8-ol (L) was characterized by 1H NMR, 13C NMR, DEPT-135 and IR spectroscopic techniques. The synthesized metal complexes were characterized using elemental analyses, (infrared, electronic and FAB mass) spectra, magnetic measurements and thermogravimetric analyses. Kinetic parameters such as order of reaction (n) and the energy of activation (Ea) are reported using the Freeman–Carroll method. The pre-exponential factor (A), the activation entropy (ΔS#), the activation enthalpy (ΔH#) and the free energy of activation (ΔG#) were calculated. Metal complexes are also screened for their in vitro antibacterial activity against a range of Gram-positive and Gram-negative organisms.

Structures containing 8-hydroxyquinoline scaffold are useful for anticancer drug development. The title ester (5-chloroquinolin-8-yl)-2-fluorobenzoate was prepared by the reaction of 2-fluorobenzoyl chloride with 5-chloro-8-hydroxyquinoline. The structure of the title compound was assigned by diverse spectroscopic techniques. Moreover, a crystallographic study was undertaken and its supramolecular characteristics were analyzed. Thus, the central ester fragment C8/O1/C10(O2)/C11 is almost planar with a root mean square (r.m.s.) deviation of 0.0612 Å and it makes dihedral angles of 76.35(6)° and 12.89(11)°, with quinoline and phenyl rings respectively. The structure shows C–H...X (X = halogen) non-classical hydrogen bonds. It also has a halogen…halogen distance less than the sum of the van der Waals radii (3.2171(15) Å). As a result of interactions with halogen atoms, chains of centrosymmetric dimer that form edge-fused R22(18) rings run parallel to the plane (100).

Looking to the pharmacological importance of 8-hydroxyquinolines, in the present study, a novel ligand 5-((1-methyl-1,2-dihydroquinolin-4-yloxy) methyl) quinolin-8-ol (MDMQ) was synthesized by the reaction of 1-methyl-1,2-dihydroquinolin-4-ol with 5-chloromethyl- 8-hydroxyquinoline hydrochloride. Its metal complexes were also prepared with Mn(II), Fe(II), Co(II), Ni(II), Cu(II) and Zn(II) salts. All the above compounds were investigated by physicochemical analysis, thermogravimetric analysis and spectroscopic techniques. In vitro antimicrobial activity of all synthesized compounds and standard drugs has been evaluated against four strains of bacteria which include two gram +ve bacteria such as Staphylococcus aureus, Bacillus megaterium and two gram −ve bacteria such as Escherichia coli, Proteus vulgaris and one fungi Aspergillus niger.