title: Spectroscopic studies on gallic acid and its azo derivatives and their iron(III) complexes.
abstract: Azo gallic derivatives and their iron(III) complexes were synthesized and characterized. The stereochemistry and the mode of bonding of the complexes were achieved based on elemental analysis, UV-Vis and IR. The thermal behaviors of the complexes were studied. The effect of pH on the electronic absorption spectra of gallic acid and its azo derivatives are discussed. Different spectroscopic methods (molar ratio, straight line method, continuous variation, slope ratio and successive method) are applied for determination of stoichiometry and pK values for the complex formation of gallic acid with iron(III) in aqueous media. Iron(III) complexes of gallic acid is formed with different ratio: 1:1, 1:2, 1:3 and 1:4 (M:L).
authors.affiliation: Chemistry Department, Faculty of Science, Alexandria University, Alexandria, Egypt.
authors.forename: Mamdouh S
authors.initials: MS
authors.lastname: Masoud
authors.affiliation: Chemistry Department, Faculty of Science, Damanhour University, Damanhour, Egypt. Electronic address: dralaae@yahoo.com.
authors.forename: Alaa E
authors.initials: AE
authors.lastname: Ali
authors.affiliation: Chemistry Department, Faculty of Science, Alexandria University, Alexandria, Egypt.
authors.forename: Sawsan S
authors.initials: SS
authors.lastname: Haggag
authors.affiliation: Faculty of Pharmacy, Alexandria University, Alexandria, Egypt.
authors.forename: Nessma M
authors.initials: NM
authors.lastname: Nasr
mesh_terms: D001391:Azo Compounds / Q000737:chemistry*; D056831:Coordination Complexes / Q000737:chemistry*; D005707:Gallic Acid / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D007501:Iron / Q000737:chemistry*; D013053:Spectrophotometry; D013055:Spectrophotometry, Infrared
chemical_list: D001391:Azo Compounds; D056831:Coordination Complexes; D005707:Gallic Acid; D007501:Iron
keywords: Complexes; DTA; Dissociation constants; Gallic acid; Spectrophotometric methods; Synthesis