- Corrosion inhibition performance of newly synthesized 5-alkoxymethyl-8-hydroxyquinoline derivatives for carbon steel in 1 M HCl solution: Experimental, DFT and Monte Carlo simulation studies
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Three new organic compounds primarily based on 8-hydroxyquinoline have been successfully synthesized and characterized via different spectroscopic methods (FTIR, 1H, and 13C NMR). The synthesized compounds, namely 5-propoxymethyl-8-hydroxyquinoline (PMHQ), 5-methoxymethyl-8-hydroxyquinoline (MMHQ) and 5-hydroxymethyl-8-hydroxyquinoline (HMHQ), were evaluated as corrosion inhibitors for carbon steel in 1 M HCl solution using electrochemical impedance spectroscopy, potentiodynamic polarization and weight loss measurements at 298 K. Electrochemical measurements confirmed that the newly synthesized 5-alkoxymethyl-8-hydroxyquinoline derivatives are mixed type corrosion inhibitors and confirmed maximum protection efficiencies of 94, 89 and 81% for PMHQ, MMHQ, and HMHQ, respectively, at the optimum concentration of 10-3 M. The EIS spectra confirmed a slightly depressed semi-circle profile with a single time constant in Bode diagrams for the three organic compounds over the whole concentration and temperature ranges studied. The adsorption of PMHQ, MMHQ, and HMHQ on the carbon steel surface followed the Langmuir adsorption isotherm. In addition, the kinetic and thermodynamic parameters for carbon steel corrosion and inhibitor adsorption, respectively, were determined and discussed. Scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) analyses supported the formation of a protective film on carbon steel in the presence of PMHQ, MMHQ, and HMHQ. Density functional theory calculations (DFT) showed that the effectiveness of the inhibitive actions of the studied compounds correlates well with their electron donating ability, whilst Monte Carlo simulations revealed that the extent and favourability of adsorption of inhibitor molecules on the carbon steel surface establish their corrosion inhibition performances.
- El Faydy,Touir,Ebn Touhami,Zarrouk,Jama,Lakhrissi,Olasunkanmi,Ebenso,Bentiss
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p. 20167 - 20187
(2018/08/16)
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- Study on Relationship Between Fluorescence Properties and Structure of Substituted 8-Hydroxyquinoline Zinc Complexes
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Organic light-emitting diodes (OLEDs) produced from 8-hydroxyquinoline metal complexes play a vital role in modern electroluminescent devices. In this manuscript, a series of 8-hydroxyquinoline derivatives were synthesized by different methods and their corresponding zinc metal complexes were prepared. The UV and fluorescence properties of the complexes were measured aiming to understand the effect of substituents at the quinoline ring on the fluorescence properties of the complexes. When the C-5 of 8-hydroxyquinoline was replaced by halogen group, the fluorescence emission wavelengths had been red-shifted, at the same time, blue-shifted of fluorescence emission wavelength was observed when the C-5 position of 8-hydroxyquinoline was substituted by electron-withdrawing group. When the C-4 position of 8-hydroxyquinolie was substituted by methyl or the C-5 position was substituted by sulfonic acid group, the corresponding zinc complexes had higher fluorescence intensity than 8-hydroxyquinolie zinc.
- Jianbo, He,Tingting, Zhou,Yongjing, Cao,Yuanyuan, Zhang,Weiqing, Yang,Menglin, Ma
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p. 1121 - 1126
(2018/08/17)
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- Intermolecular interactions in the solid state structures of neutral and N-protonated 5-alkoxymethyl-8-hydroxyquinolines
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A series of five different alkoxymethyl substituted derivatives of 8-hydroxyquinoline was synthesised both in protonated (1a-1e) and neutral (2a-2e) form. The alkoxymethyl groups are MeO (1a, 2a), EtO (1b, 2b), n-PrO (1c, 2c), iso-PrO (1d, 2d), n-BuO (1e, 2e). The compounds were characterised by single crystal X-ray diffraction and spectroscopic methods. Hirshfeld surface analysis was performed to analyse the crystal packing quantitatively. Topological analysis of the electron density distribution delivers information about the strength of the hydrogen bonds. The overall results reveal a main difference between the charged (1a-1d) and uncharged (2a-2e) compounds in the orientation of the hydroxyl group resulting in a different cyclic dimer formation. In both cases the structures are dominated by hydrogen bonding (1a-1d: O[sbnd]H?Cl, N[sbnd]H?Cl and 2a-2e: O[sbnd]H?N). Furthermore, all crystal structures show π involved interactions though taking only a minor part in the packing of the molecules.
- Schulze, Mathias M.,B?hme, Uwe,Schwarzer, Anke,Weber, Edwin
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p. 307 - 319
(2016/12/18)
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- Synthesis, spectroscopic and in-vitro antifungal studies of drug based mixed ligand complexes
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The mixed-ligand complexes of various metal(ll) with 5-chloro-7-iodo-8- hydroxyquinoline (Clioquinol) and 5-(methoxymethyl-8-quinolinol) (MMQ) were prepared. The structure of mixed-ligand complexes was investigated using spectral, physicochemical, elemental analyses and thermal studies. Magnetic moment and reflectance spectral studies reveal that an octahedral geometry has been assigned to all the prepared complexes. The ligands, metal salts, complexes, control and standard drug were tested for their in-vitro antifungal.The metal complexes exhibit good activity against fungal strains compared with parental compounds and moderate compared with the standard drug (Clioquinol).
- Chauhan,Kharadi,Patel
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experimental part
p. 1431 - 1436
(2011/10/12)
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- Microwave assisted synthesis of a small library of substituted N, N ′-Bis((8-hydroxy-7-quinolinyl)methyl)-1,10-diaza-18-crown-6 ethers
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Figure presented. N,N′-Bis-((8-hydroxy-7-quinolinyl)methyl)-1,10- diaza-18-crown-6 ether 1a and its analogue 1c are known as fluorescent sensors of magnesium in living cells. With the aim to investigate the effects of the substitution pattern on the photophysical properties of ligands 1 and their metal complexes, we developed an efficient microwaves enhanced one-pot Mannich reaction to double-armed diaza-crown ligands 1 carrying a variety of substituents. This new protocol is characterized by shorter reaction times, enhanced yields, and improved product purities with respect to the use of conventional conductive heating.
- Farruggia, Giovanna,Iotti, Stefano,Lombardo, Marco,Marraccini, Chiara,Petruzziello, Diego,Prodi, Luca,Sgarzi, Massimo,Trombini, Claudio,Zaccheroni, Nelsi
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supporting information; experimental part
p. 6275 - 6278
(2010/12/19)
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- Pharmaceutical compositions comprising iron chelators for the treatment of neurodegenerative disorders and some novel iron chelators
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Use of a compound of formula (I), wherein R1 is H or hydrocarbyl; R2 is a hydrophobic radical; R3 is 3-(C2-C6)acyl-4-hydroxyphenyl, 3-hydroxyimino (C2-C6)-alkyl-4-hydroxyphenyl, or COOZ, wherein Z is H, (C1-C6) alkyl, aryl, aryl or ar(C1-C6) alkyl; and n is 1-20; and of a compound of formula (II), wherein R4 is (C1-C6) alkyl, cyano (C1-C6) alkyl, (C1-C6) alkoxy (C1-C6) alkyl or —CH2NR7R8, wherein R7 and R8, the same or different, is each H or (C1-C6) alkyl, or together with the N atom form a saturated or unsaturated 5-7 membered ring optionally containing a further heteroatom selected from N, O or S, the further N atom being optionally substituted, and either R5 is H and R6 is (C2-C6) acyl or hydroxyimino (C2-C6) alkyl, or R5 and R6 together with the phenyl ring form a quinoline, a 1,2,3,4-tetrahydroquinoline or a perhydroquinoline ring, for the preparation of pharmaceutical compositions for the treatment of Parkinson's disease or stroke.
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Page/Page column 10-11
(2010/02/10)
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