title: Vanadium complexes with mixed O,S anionic ligands derived from maltol: synthesis, characterization, and biological studies.
abstract: Four mixed O,S binding bidentate ligand precursors derived from maltol (3-hydroxy-2-methyl-4-pyrone) have been chelated to vanadium to yield new bis(ligand)oxovanadium(IV) and tris(ligand)vanadium(III) complexes. The four ligand precursors include two pyranthiones, 3-hydroxy-2-methyl-4-pyranthione, commonly known as thiomaltol (Htma), and 2-ethyl-3-hydroxy-4-pyranthione, commonly known as ethylthiomaltol (Hetma), as well as two pyridinethiones, 3-hydroxy-2-methyl-4(H)-pyridinethione (Hmppt) and 3-hydroxy-1,2-dimethyl-4-pyridinethione (Hdppt). Vanadium complex formation was confirmed by elemental analysis, mass spectrometry, and IR and EPR (where possible) spectroscopies. The X-ray structure of oxobis(thiomaltolato)vanadium(IV),VO(tma)(2), was also determined; both cis and trans isomers were isolated in the same asymmetric unit. In both isomers, the two thiomaltolato ligands are arranged around the base of the square pyramid with the V=O linkage perpendicular; the vanadium atom is slightly displaced from the basal plane [V(1) = 0.656(3) A, V(2) = 0.664(2) A]. All of the new complexes were screened for insulin-enhancing effectiveness in streptozotocin-induced diabetes in rats, and VO(tma)(2) was profiled metabolically for urinary vanadium and ligand clearance by GFAAS and ESIMS, respectively. The new vanadium complexes did not lower blood glucose levels acutely, possibly because of rapid dissociation and excretion.
authors.affiliation: Medicinal Inorganic Chemistry Group, Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, British Columbia V6T 1Z1, Canada.
authors.forename: Vishakha
authors.initials: V
authors.lastname: Monga
authors.forename: Katherine H
authors.initials: KH
authors.lastname: Thompson
authors.forename: Violet G
authors.initials: VG
authors.lastname: Yuen
authors.forename: Vijay
authors.initials: V
authors.lastname: Sharma
authors.forename: Brian O
authors.initials: BO
authors.lastname: Patrick
authors.forename: John H
authors.initials: JH
authors.lastname: McNeill
authors.forename: Chris
authors.initials: C
authors.lastname: Orvig
mesh_terms: D000818:Animals; D001786:Blood Glucose / Q000032:analysis / Q000187:drug effects / Q000378:metabolism; D003921:Diabetes Mellitus, Experimental / Q000139:chemically induced / Q000188:drug therapy / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D007004:Hypoglycemic Agents / Q000138:chemical synthesis* / Q000627:therapeutic use; D008024:Ligands; D015394:Molecular Structure; D011753:Pyrones / Q000737:chemistry*; D051381:Rats; D013997:Time Factors; D014639:Vanadium / Q000737:chemistry* / Q000378:metabolism / Q000652:urine; D017968:Vanadium Compounds / Q000138:chemical synthesis* / Q000378:metabolism / Q000627:therapeutic use / Q000652:urine
chemical_list: D001786:Blood Glucose; D007004:Hypoglycemic Agents; D008024:Ligands; D011753:Pyrones; D017968:Vanadium Compounds; D014639:Vanadium; C008316:maltol