title: New 3,4-diaminobenzoic acid Schiff base compounds and their complexes: synthesis, characterization and thermodynamics.
abstract: Some new tetradentate Schiff base ligands (H3L) were prepared via condensation of 3,4-diaminobenzoic acid with 2-hydroxybenzaldehyde derivatives, such as 3,4-bis((E)-2,4-dihydroxybenzylideneamino)benzoic acid (H3L(1)), 3,4-bis((E)-2-hydroxy-3-methoxybenzylideneamino)benzoic acid (H3L(2)) and 3,4-bis((E)-5-bromo-2-hydroxybenzylideneamino)benzoic acid (H3L(4)). Additionally, a tetradentate Schiff base ligand 3,4-bis((E)-2-hydroxybenzylideneamino)benzoic acid (H3L(3)) and its complexes were synthesized. Their metal complexes of Co(II), Ni(II), Cu(II) and Zn(II) were prepared in good yields from the reaction of the ligands with the corresponding metal acetate. They were characterized based on IR, (1)H NMR, Mass spectroscopy and UV-Vis spectroscopy. Also, the formation constants of the complexes were measured by UV-Vis spectroscopic titration at constant ionic strength 0.1M (NaClO4), at 25 °C in dimethylformamide (DMF) as a solvent.
authors.affiliation: Chemistry Department, Faculty of Sciences, Persian Gulf University, Bushehr 75169, Islamic Republic of Iran. Electronic address: khmohammadi@pgu.ac.ir.
authors.forename: Khosro
authors.initials: K
authors.lastname: Mohammadi
authors.affiliation: Chemistry Department, Faculty of Sciences, Persian Gulf University, Bushehr 75169, Islamic Republic of Iran.
authors.forename: Mahmood
authors.initials: M
authors.lastname: Niad
authors.affiliation: Chemistry Department, Faculty of Sciences, Persian Gulf University, Bushehr 75169, Islamic Republic of Iran.
authors.forename: Tahereh
authors.initials: T
authors.lastname: Jafari
mesh_terms: D062365:Aminobenzoates / Q000138:chemical synthesis* / Q000737:chemistry*; D004583:Electrons; D007477:Ions; D008024:Ligands; D008670:Metals / Q000737:chemistry; D066244:Proton Magnetic Resonance Spectroscopy; D012545:Schiff Bases / Q000138:chemical synthesis* / Q000737:chemistry*; D013055:Spectrophotometry, Infrared; D013056:Spectrophotometry, Ultraviolet; D013816:Thermodynamics
chemical_list: D062365:Aminobenzoates; D007477:Ions; D008024:Ligands; D008670:Metals; D012545:Schiff Bases; C041192:3,4-diaminobenzoic acid
keywords: 3,4-Diaminobenzoic acid; Complexation; Formation constant; Salicylaldehyde derivatives; Tetradentate Schiff base