title: Copper(II) chemistry of the functionalized macrocycle cyclam tetrapropionic acid.
abstract: The Cu(II) complex of H(4)TETP (H(4)TETP = 1,4,8,11-tetraazatetradecane-1,4,8,11-tetrapropionic acid) is five-coordinate with a distorted square-pyramidal structure (τ = 0.45; i.e. the geometry is nearly half-way between square-pyramidal and trigonal-bipyramidal) and a relatively long Cu-N and a short Cu-O bond; the comparison between powder and solution electronic spectroscopy, the frozen solution EPR spectrum and ligand-field-based calculations (angular overlap model, AOM) indicate that the solution and solid state structures are very similar, i.e. the complex has a relatively low "in-plane" and a significant axial ligand field with a d(x(2)-y(2)) ground state. The ligand-enforced structure is therefore shown to lead to a partially quenched Jahn-Teller distortion and to a relatively low complex stability, lower than with the corresponding acetate-derived ligand H(4)TETA. This is confirmed by potentiometric titration and by the biodistribution with (64)Cu-labeled ligands which show that the uptake in the liver is significantly increased with the H(4)TETP-based system.
authors.affiliation: Universität Heidelberg, Anorganisch-Chemisches Institut, INF 270, D-69120 Heidelberg, Germany. peter.comba@aci.uni-heidelberg.de
authors.forename: Peter
authors.initials: P
authors.lastname: Comba
authors.forename: Franziska
authors.initials: F
authors.lastname: Emmerling
authors.forename: Maik
authors.initials: M
authors.lastname: Jakob
authors.forename: Werner
authors.initials: W
authors.lastname: Kraus
authors.forename: Manja
authors.initials: M
authors.lastname: Kubeil
authors.forename: Michael
authors.initials: M
authors.lastname: Morgen
authors.forename: Jens
authors.initials: J
authors.lastname: Pietzsch
authors.forename: Holger
authors.initials: H
authors.lastname: Stephan
mesh_terms: D000818:Animals; D056831:Coordination Complexes / Q000138:chemical synthesis / Q000737:chemistry* / Q000493:pharmacokinetics; D003300:Copper / Q000737:chemistry*; D018360:Crystallography, X-Ray; D004578:Electron Spin Resonance Spectroscopy; D006571:Heterocyclic Compounds / Q000737:chemistry*; D007553:Isotope Labeling; D008024:Ligands; D008297:Male; D008968:Molecular Conformation; D011422:Propionates / Q000737:chemistry; D019275:Radiopharmaceuticals / Q000138:chemical synthesis / Q000737:chemistry* / Q000493:pharmacokinetics; D051381:Rats; D017208:Rats, Wistar; D014018:Tissue Distribution
chemical_list: D056831:Coordination Complexes; D006571:Heterocyclic Compounds; D008024:Ligands; D011422:Propionates; D019275:Radiopharmaceuticals; C024560:cyclam; D003300:Copper; C029658:propionic acid