Potentiometric and spectroscopic studies on aluminium(III) complexes of some catechol derivatives.
The interactions of aluminium(III) ion with the triprotic catechol derivatives (H3L), 2,3-dihydroxybenzoic acid (2,3-DHBA), 3,4-dihydroxyphenylacetic acid (3,4-DHPA), 3,4-dihydroxybenzoic acid (3,4-DHBA), and 3,4-dihydroxyhydrocinnamic acid (3,4-DHHCA) were investigated in aqueous solution at 25.0 degrees C. The Calvin-Bjerrum titration method was adopted for the determination of formation constants of proton-ligand and aluminium(III)-ligand complexes. Potentiometric and spectroscopic results indicated that these catechol derivatives exhibit a true bidentate character. The chelation occurs via their catecholate sites, with the exception of 2,3-DHBA. In the case of 2,3-DHBA complexes, the dominant species are either the salicylate type (COO-, O-) or catecholate type (O-, O-) complex. The protonation constants of ligands and their formation constants of Al(III) complexes were also correlated. The order of decreasing stabilities of complexes is: 3,4-DHPA>3,4-DHBA>3,4-DHHCA>2,3-DHBA.
Türkel
Naciye
N
Department of Chemistry, Faculty of Arts and Sciences, Uludağ University, Bursa, Turkey. nturkel@uludag.edu.tr
Berker
Melek
M
Ozer
Ulviye
U
D017607:Aluminum Compounds / Q000737:chemistry* / Q000493:pharmacokinetics; D001565:Benzoates / Q000737:chemistry; D002396:Catechols / Q000737:chemistry*; D002614:Chelating Agents / Q000737:chemistry; D008024:Ligands; D011199:Potentiometry / Q000379:methods; D011522:Protons; D013056:Spectrophotometry, Ultraviolet / Q000379:methods
D017607:Aluminum Compounds; D001565:Benzoates; D002396:Catechols; D002614:Chelating Agents; D008024:Ligands; D011522:Protons