title: Model complexes with naturally occurring ligands (salicylglycine and imidazol) and the biometals copper and cobalt.
abstract: Two new complexes [Cu(Imz)(4)Cl(2)][Cu(Imz)(4)Cl] (2)(2-OH-Hip)(2) (1) and [Co(2-OH-Hip)(Imz)(3)].H(2)O (2) (with Imz=Imidazol and 2-OH-Hip=2-hydroxyhippuric acid) were prepared and characterized. The molecular structures and the solution and solid state behavior of the complexes were investigated. Complex 1 crystallizes in the monoclinic space group P2(1)/c with a=16.880(1), b=8.046(1), c=24.683(1) A, beta=107.88(1) degrees, and Z=2, while complex 2 crystallizes in the orthorhombic space group Pbca with a=11.712(2), b=15.741(4), c=22.254(4) A, and Z=8. The [Cu(Imz)(4)Cl(2)][Cu(Imz)(4)Cl](2)(2-OH-Hip)(2) solid consists in two distinct monomeric Cu(II) complexes: one of them is neutral octahedral [Cu(Imz)(4)Cl(2)] and the other, charged square basis pyramida [Cu(Imz)(4)Cl](+). The 2-hydroxyhippuric acid, which here acts as a counter ion, is deprotonated at its carboxylic group. Cobalt(III) ion in [Co(2-OH-Hip)(Imz)(3)].H(2)O is at the center of an octahedral environment, coordinated to three Imidazol ligands and to a triply deprotonated 2-hydroxyhippuric acid molecule acting as a tridentate ligand. Aqueous solution equilibrium of the quaternary system Cu(2+)/2-OH-Hip/Imz/H(+) was studied by potentiometric titrations.
authors.affiliation: Centro de Química Inorgánica, CONICET, Facultad de Ciencias Exactas, UNLP, C. Correo 962, 1900 La Plata, Argentina.
authors.forename: Evelina G
authors.initials: EG
authors.lastname: Ferrer
authors.forename: Ana C
authors.initials: AC
authors.lastname: González Baró
authors.forename: Eduardo E
authors.initials: EE
authors.lastname: Castellano
authors.forename: Oscar E
authors.initials: OE
authors.lastname: Piro
authors.forename: Patricia A M
authors.initials: PA
authors.lastname: Williams
mesh_terms: D001665:Binding Sites; D003035:Cobalt / Q000737:chemistry* / Q000378:metabolism; D003300:Copper / Q000737:chemistry* / Q000378:metabolism; D006626:Hippurates / Q000737:chemistry / Q000378:metabolism; D006358:Hot Temperature; D006863:Hydrogen-Ion Concentration; D007093:Imidazoles / Q000737:chemistry* / Q000378:metabolism; D008024:Ligands; D009942:Organometallic Compounds / Q000737:chemistry*; D011199:Potentiometry; D013055:Spectrophotometry, Infrared
chemical_list: C490238:(Co(2-hydroxyhippuric acid)(imidazol)(3)).H(2)O (2); C490236:(Cu(Imidazol)(4)Cl(2))(Cu(imidazole)(4)Cl)(2)(2-hydroxyhippuric acid)(2); D006626:Hippurates; D007093:Imidazoles; D008024:Ligands; D009942:Organometallic Compounds; D003035:Cobalt; C000693:salicylurate; D003300:Copper