In-situ fluorescence studies of aluminum ion complexation by 8-hydroxyquinoline covalently bound to silica

Fiber-Optic Raman Spectroscopy for in Situ Monitoring of Metal-Ion Complexation by Ligands Immobilized onto Silica Gel

“…16 For example, Cu 21 forms a binary 8HQ complex in free solution with form ation constants 10 12 and 10 11 for binding the rst and second ligand, respectively. 16,29 Several studies in the literature 9,[17][18][19] have reported that the complexation ratio of metals to silica-immobilized 8HQ is 1 to 1. However, one of the disadvantages of previous studies of metal-ion binding to solid supports is that the total complex was determined with no ability to distinguish between different metal-ligand structures on the surface.…”

“…Ex situ uorescence 7 and photoacoustic 8 spectroscopy have been used to observe electronic spectra of silica-immobilized metal ion complexes of trihydroxyazobenzene and N- (2-pyridyl)acetam ide ligands, respectively. Fluorescence detection has been adapted to ow injection m ethods for in situ detection of aluminum-ion complexation to silica-immobilized 8-hydroxyquinoline (8HQ), 9 where the equilibrium constant for binding and its dependence on the surface potential were investigated. W hile uorescent m etal complexes allow detection of bound m etal ions at very low concentrations, the usual lack of uorescence from the free ligand precludes accurate determination of the ratio of bound to free form s. In general, electronic spectroscopy of these species is not ver y sensitive to structural differences between various form s of the ligand.…”

“…13 In the present work, we address the problem of in situ detection of metal-ion complexation to ligands covalently bound to silica gel. Silica gel is often employed as a support m aterial for imm obilized ligands [1][2][3][4][5][6][7][8][9] since it is inert, stable, and available in high purity and with a high speci c surface area, which can provide a high speci c binding capacity. 14 Silica gel has excellent optical transparency from the ultraviolet through the near-infrared, which makes it a reasonable support to be investigated by Raman scattering.…”

Oxinate-Aluminum(III) Nanostructure Assemblies Formed via In-situ and Ex-situ Oxination of Gold-Self-Assembled Monolayers Characterized by Electrochemical, Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy, and X-ray Photoelectron Spectroscopy Methods

“…The 8HQ unit is an ideal building block in metallosupramolecular chemistry. Thus, the 8HQ and its derivatives have been immobilized on different surfaces including polystyrene derivatives [2,3], resins and zeolites [4][5][6], cellulose [7], polyacrylonitrile [8], malachite [9], modified glass [10], silica [11][12][13] and silver [14].…”

Solid Phase Extraction of Inorganic Mercury Using 5‐Phenylazo‐8‐hydroxyquinoline and Determination by Cold Vapor Atomic Fluorescence Spectroscopy in Natural Water Samples

“…Stability constant of Ca(II) with immobilized 8-HQ was also determined by [ 3 ] with slightly higher value of log⁡⁡ K 1 of 3.7. Moreover, Weaver and Harris [ 4 ] calculated the stability constant of aluminum with alkyl-immobilized 8-HQ and found it to be log⁡⁡ K 1 0.8. High stability constants were found for Cd(II) with 8-HQ immobilized on controlled pore glass (CPG) ranging from 10 9 –10 11 [ 5 ].…”