- Photodynamic fluorescent metal ion sensors with parts per billion sensitivity
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We report herein the synthesis and spectroscopic study of the first spiropyrandinolines that function as sensors for metal ions in the parts per billion range. These systems operate by either photochemically or chemically induced reversible formation of merocyanine metal ion complexes. The application of this novel photodynamic sensing material to sensor technology is discussed.
- Winkler, Jeffrey D.,Bowen, Corinne M.,Michelet, Veronique
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- Design and synthesis of a solvent-dependent fluorescent probe for dual selective detection of Mg2+ ion and Zn2+ ion
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A solvent-dependent fluorescent probe QC for the dual detection of Mg2+ ion and Zn2+ ion has been constructed based on a Schiff base compound, in which 8-hydroxyquinoline served as not only a fluorophore but also a recognition group. Among the various tested metal ions, this probe exhibited high sensitivity and good selectivity toward Mg2+ ion in acetonitrile and Zn2+ ion in EtOH-H2O (9:1, v/v), respectively. With the treatment of Mg2+ ion or Zn2+ ion, 1:2 complex was formed between QC and Mg2+ ion, which inhibited the PET processes caused by the lone pair electrons from the nitrogen atom of the -C = N group and the nitrogen atom of quinoline moiety, resulting in the fluorescence enhancement for Mg2+ ion. Whereas a 1:1 complex was formed between QC and Zn2+ ion, which inhibited the PET process only caused by the lone pair electrons from the nitrogen atom of the -C = N group, resulting in the fluorescence enhancement at a shorter wavelength. The detection limit was calculated as low as 6.28 × 10?8 M for Mg2+ ion and 2.36 × 10?7 M for Zn2+ ion. DFT analysis further supported this concept to design the probe.
- Fu, Zhen-Hai,Qin, Jing-Can,Wang, Min,Zhang, Zhi-Hong
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- DNA-binding and anti-oxidation properties of binuclear lanthanide(III) complexes of 8-hydroxyquinoline-7-carbaldehyde-(isonicotinyl)hydrazone
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Binuclear complexes [LnL(NO3)(H2O)2] 2 were prepared from the Schiff base 8-hydroxyquino-line-7- carbaldehyde-(isonicotinyl)hydrazone (H2L) and equivalent molar amounts of Ln(NO3)3 · 6H2O (Ln = La 3+, Nd3+, Sm3+, Eu3+, Gd 3+, Dy3+, Ho3+, Er3+, Yb 3+), respectively. The ligand is dibasic tetradentate and the dimerization occurs through the phenolate oxygen atoms leading to a central four-membered (LnO)2-ring. The ligand and all the Ln(III) complexes can bind to calf thymus DNA through intercalation with binding constants of 105-106 (molL-1)-1, and they show strong scavenging abilities on hydroxyl radicals and superoxide radicals. The values of SC50 of Ln(III) complexes for HO? and O2-. are 2.344-13.33 and 4.459-28.48 μmolL -1, respectively. Ln(III) complexes present stronger binding abilities to DNA and stronger anti-oxidation properties than ligand. Complex containing hydroxyl unit shows stronger scavenging abilities on hydroxyl radical, while complex containing N-heteroaromatic substituent shows stronger scavenging abilities on superoxide radicals. Furthermore, earlier rare metal complexes show stronger scavenging abilities on both hydroxyl radicals and superoxide radicals.
- Liu, Yongchun,Zhang, Kejun,Lei, Ruixia,Liu, Jianning,Zhou, Tianlin,Yang, Zheng-Yin
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- Quinoline-based highly selective and sensitive fluorescent probe specific for Cd2+ detection in mixed aqueous media
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Quinoline-based fluorescent probe as a recognition unit was designed and synthesized in this study. The probe R1 displayed excellent selectivity and sensitivity for cadmium ions (Cd2+) over a wide range of metal ions in acetonitrile-water (MeCN-H2O) mixed solution. In order to better understand the recognition mechanism between probe and Cd2+, the density functional theory calculations were performed. Finally, the colorimetric experiment result was observed and conveniently monitored by the naked eye, and a visual detection limit of 4 × 10?6 mol L?1 was achieved. These experimental results indicated the promising potential of the probe to detect Cd2+ in biological system. Furthermore, the probe R1 was successfully used for the highly sensitive detection of Cd2+ in living cells.
- Ding, Xiaohu,Zhang, Feifei,Bai, Yinjuan,Zhao, Junxia,Chen, Xia,Ge, Man,Sun, Wei
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- In Vitro Antimicrobial and in Vivo Molluscicidal Potentialities of Fe(III), Co(II) and Ni(II) Complexes Incorporating Symmetrical Tetradentate Schiff bases (N2O2)
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This paper aimed at synthesizing symmetrical Schiff base ligands derived from the primary amine 1,2-bis(2-aminophenylthio)ethane condensed with 7-formyl-8-hydroxyquinoline and 2-hydroxy-1-naphthaldehyde. The synthesised ligands were used for preparing metal complexes with the iron triad metals. The symmetrical tetradentate (N2O2) Schiff base ligands SL1 and SL2 forms mononuclear complexes with square planar geometry in case of Co(II) and Ni(II) complexes, while an octahedral geometry was obtained for the Fe(III) complexes. The molar conductance quantification showed that the complexes were non-ionic. In vitro antimicrobial potential examination of the free ligands indicated weak activity and the corresponding complexes showed enhanced activity. Moreover, the In vivo molluscicidal potential of the tested chemicals showed good activity against the tested land snails. Ligands showed activity at concentration of 1000 ppm while their metal complexes show activity at concentration of 500 ppm. The highest activity (LC50) of complexes was shown at concentration of 5000 ppm.
- Alosaimi, Amal M.,Mannoubi, Ines El,Zabin, Sami A.
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p. 373 - 384
(2020/07/23)
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- Nano cuboids: Impact of 8-hydroxyquinoline on tryptophan properties and its applications
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N-terminal tryptophan residues can be labeled with fluorophore by chemical reaction. Here in we report conjugation of 8-hydroxyquinoline (as fluorophore) with tryptophan using Schiff-base condensation reaction to decipher the impact of 8-hydroxyquinoline on the fluorescence and self-assembly properties of tryptophan in water. This water-soluble hydroxyquinoline–tryptophan (HQ-W1) conjugate has been demonstrated to have Aggregation Induced Emission (AIE) phenomena in water. HQ-W1 undergo spontaneous self-assembly to form nano cuboidal superstructures having 200–500 nm diameter and 300–650 nm length. In metal-ion binding studies this HQ-W1 shows selective fluorescence enhancement (14.5-fold) in the presence of Al3+ ions. The detection limit is 3.0 nM (UV method) and 3.53 nM (FI method). The AIE utility of HQ-W1 has been demonstrated by developing latent fingerprints.
- Sharma, Poonam,Singh, Prabhpreet
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supporting information
(2020/02/13)
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- Synthesis, electrochemical and spectroscopic characterization of selected quinolinecarbaldehydes and their Schiff base derivatives
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A new approach to the synthesis of selected quinolinecarbaldehydes with carbonyl groups located at C5 and/or in C7 positions is presented in this paper in conjunction with spectroscopic characterization of the products. The classical Reimer-Tiemann, Vilsmeier-Haack and Duff aldehyde synthesis methods were compared due to their importance. Computational studies were carried out to explain the preferred selectivity of the presented formylation transformations. A carbene insertion reaction based on Reimer-Tiemann methodology is presented for making 7-bromo-8-hydroxyquinoline-5-carbaldehyde. Additionally, Duff and Vilsmeier-Haack reactions were used in the double formylation of quinoline derivatives and their analogues benzo[h]quinolin-10-ol, 8-hydroxy-2-methylquinoline-5,7-dicarbaldehyde, 8-(dimethylamino) quinoline-5,7-dicarbaldehyde and 10-hydroxybenzo[h]quinoline-7,9-dicarbaldehyde. Four Schiff base derivatives of 2,6-diisopropylbenzenamine were prepared from selected quinoline-5-carbaldehydes and quinoline-7-carbaldehyde by an efficient synthesis protocol. Their properties have been characterized by a combination of several techniques: MS, HRMS, GC-MS, FTIR, electronic absorption spectroscopy and multinuclear NMR. The electrochemical properties of 8-hydroxy-quinoline-5-carbaldehyde, 6-(dimethylamino)quinoline-5-carbaldehyde and its methylated derivative were investigated, and a strong correlation between the chemical structure and obtained reduction and oxidation potentials was found. The presence of a methyl group facilitates oxidation. In contrast, the reduction potential of methylated compounds was more negative comparing to non-methylated structure. Calculations of frontier molecular orbitals supported the finding. The structures of 8-hydroxy-2-methylquinoline-5,7-dicarbaldehyde and four Schiff bases were determined by single-crystal X-ray diffraction measurements.
- Wantulok, Jakub,Szala, Marcin,Quinto, Andrea,Nycz, Jacek E.,Giannarelli, Stefania,Sokolová, Romana,Ksi??ek, Maria,Kusz, Joachim
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- Antioxidation and DNA-binding properties of binuclear lanthanide(III) complexes with a schiff base ligand derived from 8-hydroxyquinoline-7- carboxaldehyde and benzoylhydrazine
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8-Hydroxyquinoline-7-carboxaldehyde (8-HQ-7-CA), Schiff-base ligand 8-hydroxyquinoline-7-carboxaldehyde benzoylhydrazone, and binuclear complexes [LnL(NO3)(H2O)2]2 were prepared from the ligand and equivalent molar amounts of Ln(NO3)·6 H 2O (Ln=La3+, Nd3+, Sm3+, Eu 3+, Gd3+, Dy3+, Ho3+, Er 3+, Yb3+, resp.). Ligand acts as dibasic tetradentates, binding to LnIII through the phenolate O-atom, N-atom of quinolinato unit, and C=N and -O-C=N- groups of the benzoylhydrazine side chain. Dimerization of this monomeric unit occurs through the phenolate O-atoms leading to a central four-membered (LnO)2 ring. Ligand and all of the LnIII complexes can strongly bind to CT-DNA through intercalation with the binding constants at 105-106 m-1. Moreover, ligand and all of the LnIII complexes have strong abilities of scavenging effects for hydroxyl (HO.) radicals. Both the antioxidation and DNA-binding properties of LnIII complexes are much better than that of ligand. Copyright
- Liu, Yongchun,Zhang, Kejun,Wu, Yun,Zhao, Junying,Liu, Jianning
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p. 1533 - 1544
(2012/11/07)
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- Synthesis of mixed schiff base complexes of Cu(II) and Ni(II) and their spectral, magnetic and antifungal studies
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Mixed ligand schiff base complexes of Cu(II) and Ni(II) derived from 7-formyl-8-hydroxyquinoline and 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-methoxyacetophenone, 2-hydroxy-1-acetophenone or 1-hydroxy-2-acetophenone and ethylenediamine have been synthesised and their spectral, magnetic and antifungal studies carried out.
- Patel, V. K.,Vasanwala, A. M.,Jejurkar, C. R.
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p. 719 - 721
(2007/10/02)
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