title: Lipophilicity of kinetically labile metal complexes through the example of antidiabetic Zn(II) and VO(IV) compounds.
abstract: The lipophilic character of several carrier ligands of antidiabetic Zn(II) and VO(IV) metal complexes were characterized by the traditional saturation shake flask method based on n-octanol/water partitioning. The transfer of the neutral ligand species to the organic phase was followed by UV spectrophotometry at various pH and the partition and distribution coefficients were calculated with the help of the proton dissociation constants and the spectra of the individual ligand species. Partition and distribution coefficients of the Zn(II) and VO(IV) complexes were determined by analysis of the metal ion content of the aqueous phases before and after separation by ICP-AES, their UV spectra and the corresponding concentration distribution curves. Results revealed the fairly hydrophilic character both the carrier ligands and their neutral Zn(II) and VO(IV) complexes. A quasi-linear relationship was found between logP of the ligands and that of the metal species in the case of the ligands studied with the exception of the picolinates. Importance of the knowledge of the chemical speciation (i.e. stoichiometry and stability constants) was also highlighted for the characterization of the lipophilic character of the kinetically labile metal complexes.
authors.affiliation: Department of Inorganic and Analytical Chemistry, University of Szeged, PO Box 440, H-6701 Szeged, Hungary. enyedy@chem.u-szeged.hu
authors.forename: Eva A
authors.initials: EA
authors.lastname: Enyedy
authors.forename: Dominik
authors.initials: D
authors.lastname: Hollender
authors.forename: Tamás
authors.initials: T
authors.lastname: Kiss
mesh_terms: D002712:Chlorides / Q000737:chemistry; D007004:Hypoglycemic Agents / Q000737:chemistry*; D007700:Kinetics; D008024:Ligands; D008055:Lipids / Q000737:chemistry*; D008956:Models, Chemical; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000737:chemistry*; D021281:Quantitative Structure-Activity Relationship; D012995:Solubility; D012996:Solutions; D013054:Spectrophotometry, Atomic; D014638:Vanadates / Q000737:chemistry*; D017968:Vanadium Compounds / Q000737:chemistry; D014867:Water / Q000737:chemistry; D015032:Zinc / Q000737:chemistry*; D017967:Zinc Compounds / Q000737:chemistry
chemical_list: D002712:Chlorides; D007004:Hypoglycemic Agents; D008024:Ligands; D008055:Lipids; D009942:Organometallic Compounds; D012996:Solutions; D017968:Vanadium Compounds; D017967:Zinc Compounds; D014867:Water; D014638:Vanadates; C034028:vanadyl sulfate; C016837:zinc chloride; D015032:Zinc