Spectroscopic studies of proton-transfer and metal-ion binding of a solution-phase model for silica-immobilized 8-hydroxyquinoline

Uibel, Rory H.; Harris, Joel M.

doi:10.1016/s0003-2670(03)00896-1

Cited by 8 publications

(6 citation statements)

References 38 publications

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“…The initial synthesis of the silane-linked ligand is a modification , of a reaction described by Long and Schofield, whereby a diazonium salt of an aromatic amine is coupled to 8-HQ via an azo linkage. The reaction begins with dissolving equal molar amounts of 8-HQ and p -aminophenyltrimethoxysilane (0.04 mmol) into 10 mL of water containing 0.08 mmol of HCl in a 100-mL round-bottom flask.…”

Section: Methodsmentioning

confidence: 99%

Templating of Multiple Ligand Metal Ion Complexation Sites in 8-Hydroxyquinoline-Modified Silica Sol−Gel Materials Investigated by in Situ Raman Spectroscopy

Uibel

Harris

2005

Anal. Chem.

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Metal ion templating in a sol-gel synthesis is used to develop multiligand 8-hydroxyquinoline binding sites in porous silica structures. The acid-base equilibria and the metal ion binding equilibria and stoichiometry of these materials are investigated by in situ Raman spectroscopy. This technique is capable of resolving spectral responses of the free ligand and its acid-base forms along the monomeric and dimeric ligand complexes with Cu2+. The proton-transfer equilibrium constants and first ligand binding equilibrium constant to Cu2+ for the metal ion-templated silica are equivalent to surface-immobilized 8HQ on silica gel. The second ligand binding constant to Cu2+, however, is comparable to the first ligand binding constant, which differs from free-solution behavior, where an order of magnitude smaller value is expected. The free energy available for binding the second ligand within the templated material is comparable to the first ligand, probably due to the nearly optimal location of the second ligand for binding, based on the templating that is done during this synthesis. The metal ion concentration responses of sol-gels prepared with varying amounts of metal ion during the syntheses were also tested, and the results indicate control over the fraction of templated binding sites.

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Section: Methodsmentioning

confidence: 99%

Templating of Multiple Ligand Metal Ion Complexation Sites in 8-Hydroxyquinoline-Modified Silica Sol−Gel Materials Investigated by in Situ Raman Spectroscopy

Uibel

Harris

2005

Anal. Chem.

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“…[27] The HOMO and LUMO energy values for the silver complex were utilized to calculate its electronegativity, χ = (I + A)/2, chemical hardness, η = (I − A)/2, and global softness S = 1/2η, where I and A are ionization potential and electron affinity, respectively, and I = −E HOMO and A = −E LUMO . [28,29] Natural bond order calculations were performed at the same level using the NBO 3.1 program as implemented in the Gaussian 09W software package in order to qualitatively measure the intermolecular charge delocalization in the studied silver complex. The molecular orbitals (MOs) were constructed using the GaussView 5.08 visualization program.…”

Section: Methodsmentioning

confidence: 99%

Effect of the formation of silver nano‐binuclear complex on the refinement of cytotoxic and antibacterial potency of coumarin Schiff base: Spectroscopy, thermal, X‐ray diffraction analyses and density functional theory calculations

El-Ansary

Moustafa

Abdel-Kader

et al. 2019

Applied Organom Chemis

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A new Schiff base (SCH) was prepared using 8‐acetyl‐7‐hydroxy‐4‐methylcoumarin and sulfaclozine. Its silver complex was also synthesized. These compounds were subjected to elemental and spectral analyses. The silver complex was also subjected to thermogravimetric analysis, molar conductance measurements, scanning electron microscopy, energy‐dispersive X‐ray analysis and X‐ray diffraction measurements. The formula of the complex was determined as [(Ag2SCH(NO3)2]. The molar conductance indicates its non‐electrolyte character. The electronic structure and nonlinear optical parameters of SCH and its complex were investigated theoretically at the B3LYP/GENECP level. The geometry of the studied complex is non‐planar as indicated from the dihedral angles between central Ag metal ion and coordinated centres of SCH. Density functional theory calculations were also carried out to calculate the global properties of hardness, global softness and electronegativity. The calculated energy gap between HOMO and LUMO energies shows that charge transfer occurs within the studied complex. The total static dipole moment, the mean polarizability, the anisotropy of the polarizability and the mean first‐order hyperpolarizability were calculated and compared with those of urea as a reference material. The results of the mean first‐order hyperpolarizability showed that SCH and its silver complex are excellent candidates as nonlinear optical materials. The compounds were screened for their antimicrobial effect against various species of bacteria and fungi. Their anticancer activities were evaluated in vitro against the human cancer cell line MCF‐7 (human breast adenocarcinoma).

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“…8‐hydroxyquinoline is an actual copper (II) and zinc (II) chelator and inhibits the ubiquitination and asparagine hydroxylation of the hypoxia‐inducible factor leading to an expression of its target genes . Many researches have been employed to fully understand of the complexing ability of phenylazo‐8‐hydroxyquinoline and 5‐(p‐phenylazo)‐8‐hydroxyquinoline versus different metal ions . Proton‐ligand dissociation constants of 5‐phenylazo‐8‐hydroxylquinoline derivatives and metal–ligand stability constants of their complexes with metal ions (La 3+ , Ce 3+ , Pr 3+ , Zr 4+ , Hf 4+ and Th 4+ ) have been obtained potentiometrically .…”

Section: Introductionmentioning

confidence: 99%

Synthesis, characterization, electronic structure, and non‐linear optical properties (NLO) of Mn(II), Co(II), Ni(II), Cu(II) and Zn(II) complexes with 5‐phenylazo‐8‐hydroxyquinoline using DFT approach

Abdel‐Latif

Moustafa

2017

Applied Organom Chemis

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5-phenylazo-8-hydroxyquinoline and its newly metal complexes with Mn(II), Co(II), Ni(II), Cu(II) and Zn(II) metal ions have been prepared and characterized using different analytical techniques. The complexes are distorted octahedral binding via one oxygen and nitrogen atoms of the ligand; two/three coordinated water molecules. 1:1 complexes contain one chloride or OH − ion and some complexes have one or two water of hydration whereas 1:2 complexes contain only two coordinated water molecules in their coordination spheres. All complexes behave as neutral in dimethylformamide (DMF). The electronic structure and non-linear optical parameters NLO of the complexes (ML and ML2) are investigated theoretically at the B3LYP/GEN level of theory. The geometries of the studied complexes are non-planner. The calculated E HOMO and E LUMO energies of the studied complexes were used to calculate the global properties; hardness (η), global softness (S) and electronegativity (χ). The total dipole moment (μ tot ), static total and anisotropy of polarizability (α, Δα) and static first hyperpolarizability (β) values were calculated and compared with urea as a reference compound. The studied complexes show promising optical properties.

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Spectroscopic studies of proton-transfer and metal-ion binding of a solution-phase model for silica-immobilized 8-hydroxyquinoline

Cited by 8 publications

References 38 publications

Templating of Multiple Ligand Metal Ion Complexation Sites in 8-Hydroxyquinoline-Modified Silica Sol−Gel Materials Investigated by in Situ Raman Spectroscopy

Templating of Multiple Ligand Metal Ion Complexation Sites in 8-Hydroxyquinoline-Modified Silica Sol−Gel Materials Investigated by in Situ Raman Spectroscopy

Effect of the formation of silver nano‐binuclear complex on the refinement of cytotoxic and antibacterial potency of coumarin Schiff base: Spectroscopy, thermal, X‐ray diffraction analyses and density functional theory calculations

Synthesis, characterization, electronic structure, and non‐linear optical properties (NLO) of Mn(II), Co(II), Ni(II), Cu(II) and Zn(II) complexes with 5‐phenylazo‐8‐hydroxyquinoline using DFT approach

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