Potentiometric, conductometric and ³¹P NMR titrations have been applied to study interactions between myo-inositol hexakisphosphate (phytic acid), (±)-myo-inositol 1,2,3,5-tetrakisphosphate and (±)-myo-inositol 1,2,3-trisphosphate with iron(III) ions. Potentiometric and conductometric titrations of myo-inositol phosphates show that addition of iron increases acidity and consumption of hydroxide titrant. By increasing the Fe(III)/InsP(6) ratio (from 0.5 to 4) 3 mol of protons are released per 2 mol of iron(III). At first, phytates coordinate iron octahedrally between P2 and P1,3. The second coordination site represents P5 and neighbouring P4,6 phosphate groups. Complexation is accompanied with the deprotonation of P1,3 and P4,6 phosphate oxygens. At higher concentration of iron(III) intermolecular P-O-Fe-O-P bonds trigger formation of a polymeric network and precipitation of the amorphous Fe(III)-InsP(6) aggregates. (31)P NMR titration data complement the above results and display the largest chemical shift changes at pD values between 5 and 10 in agreement with strong interactions between iron and myo-inositol phosphates. The differences in T(1) relaxation times of phosphorous atoms have shown that phosphate groups at positions 1, 2 and 3 are complexated with iron(III). The interactions between iron(III) ions and inositol phosphates depend significantly on the metal to ligand ratio and an attempt to coordinate more than two irons per InsP(6) molecule results in an unstable heterogeneous system.
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http://dx.doi.org/10.1016/j.carres.2010.12.021 | DOI Listing |
Chemosphere
December 2024
V.V. Voevodsky Institute of Chemical Kinetics and Combustion SB RAS, 3 Institutskaya str., 630090, Novosibirsk, Russian Federation. Electronic address:
Acta Crystallogr C Struct Chem
December 2024
University of Melbourne, School of Chemistry, Grattan Street, Parkville, 3052, Australia.
Dalton Trans
December 2024
Federal Research Center of Problems of Chemical Physics and Medicinal Chemistry, Russian Academy of Sciences, Chernogolovka, Moscow Region 142432, Russia.
Small Methods
October 2024
Department of Chemistry, Engineering Faculty, Inorganic Chemistry Department, Istanbul University-Cerrahpasa, Istanbul, 34320, Turkey.
A thiosemicarbazone-based iron(III) complex is prepared and used in the preparation of a supercapacitor electrode material. This electrode is produced by a solvothermal reaction of polypyrrole and the complex on carbon felt. The characterization of the complex and material is carried out using UV-vis, elemental analysis, FT-IR, XRD, BET, and TGA methods, and the surface morphology is examined using SEM technique.
View Article and Find Full Text PDFInt J Biol Macromol
November 2024
Department of Chemistry, College of Science, Princess Nourah bint Abdulrahman University, P.O. Box 84428, Riyadh 11671, Saudi Arabia. Electronic address:
A nanocomposite of tannic acid and cellulose nanowhiskers (CNW)-reinforced polysulfone (PSF) was used to develop a metallochromic nanofibrous membrane sensor for iron(III) in aqueous media. Tannic acid was used as an active detecting probe, whereas the CNW@PSF composite was employed as a hosting material. Cellulose nanowhiskers (7-12 nm) were obtained from microcrystalline cellulose (MCC).
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