title: Stability of the complexes of some lanthanides with coumarin derivatives. I. Cerium(III)-4-methyl-7-hydroxycoumarin.
abstract: A complex of cerium(III) with 4-methyl-7-hydroxycoumarin was synthesized by mixing water solutions of cerium(III) nitrate and 4-methyl-7-hydroxycoumarin sodium salt in a metal-to-ligand molar ratio of 1:2. The complex was characterized and identified by elemental analysis, conductometry, IR, 1H and 13C NMR-spectroscopy, mass spectral data, DTA and TGA. Thermal analysis of the complex indicated the formation of a compound of the composition CeR2(OH).5H2O, R standing for the ligand. The reaction of cerium(III) with 4-methyl-7-hydroxycoumarin was studied in detail by the spectrophotometric method. The stepwise formation of two complexes, vis., CeR2+ and CeR2+, was established in the pH region studied. The equilibrium constants for 1:1 and 1:2 complexes were determined to be 10.72 and 9.22, respectively.
authors.affiliation: Department of Chemistry, Faculty of Pharmacy, Medical University, Sofia 1000, Bulgaria. irenakostova@yahoo.com
authors.forename: Irena P
authors.initials: IP
authors.lastname: Kostova
authors.forename: Ilia I
authors.initials: II
authors.lastname: Manolov
authors.forename: Maritza K
authors.initials: MK
authors.lastname: Radulova
mesh_terms: D000465:Algorithms; D000925:Anticoagulants / Q000138:chemical synthesis* / Q000737:chemistry*; D002563:Cerium / Q000737:chemistry*; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D003374:Coumarins / Q000138:chemical synthesis* / Q000737:chemistry* / Q000494:pharmacology*; D004355:Drug Stability; D006863:Hydrogen-Ion Concentration; D007202:Indicators and Reagents; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D009942:Organometallic Compounds / Q000138:chemical synthesis* / Q000494:pharmacology*
chemical_list: C493506:(7-hydroxy-4-methylcoumarin)cerium(III); D000925:Anticoagulants; D003374:Coumarins; D007202:Indicators and Reagents; D009942:Organometallic Compounds; D002563:Cerium