title: Phosphate binding by a novel Zn(II) complex featuring a trans-1,2-diaminocyclohexane ligand. Effective anion recognition in water.
abstract: In this work we have investigated the binding properties of a new synthetic receptor for phosphate anions that combines metal ion coordination with electrostatic and H-bonding interactions. The described receptor is obtained by assembling an iminodiacetic (IDA) fragment, as a Zn(II) binding site, with a polyamine macrocyclic portion containing two trans-1,2-diaminocyclohexane (DAC) units and a pyrrole ring, as a cationic binding site, into an adaptive structure appropriately spanning the length of di- and tridentate phosphates. Potentiometric measurements together with (1)H and (31)P NMR investigation showed that, in a wide pH range including values of physiological interest, the Zn(II) complex of the receptor binds di- and triphosphates, such as ADP, ATP, pyrophosphate (PP) and triphosphate (TP), far better than monophosphate (MP), and that TP is poorly bound by methyliminodiacetate (MIDA) as a model for the Zn(II) binding site. Besides the excellent selectivity over other phosphates, the affinity for TP is the largest reported to date for Zn(II) complexes in water.
authors.affiliation: Dipartimento di Chimica "Ugo Schiff", Università di Firenze, Polo Scientifico e Tecnologico, I-50019 Sesto Fiorentino, Firenze, Italy. andrea.bencini@unifi.it.
authors.forename: Oscar
authors.initials: O
authors.lastname: Francesconi
authors.forename: Matteo
authors.initials: M
authors.lastname: Gentili
authors.forename: Francesco
authors.initials: F
authors.lastname: Bartoli
authors.forename: Andrea
authors.initials: A
authors.lastname: Bencini
authors.forename: Luca
authors.initials: L
authors.lastname: Conti
authors.forename: Claudia
authors.initials: C
authors.lastname: Giorgi
authors.forename: Stefano
authors.initials: S
authors.lastname: Roelens
mesh_terms: D000838:Anions / Q000737:chemistry; D001665:Binding Sites; D003514:Cyclohexylamines / Q000737:chemistry*; D008024:Ligands; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000138:chemical synthesis / Q000737:chemistry*; D010710:Phosphates / Q000737:chemistry*; D014867:Water / Q000737:chemistry*; D015032:Zinc / Q000737:chemistry*
chemical_list: D000838:Anions; D003514:Cyclohexylamines; D008024:Ligands; D009942:Organometallic Compounds; D010710:Phosphates; D014867:Water; C030435:1,2-cyclohexanediamine; D015032:Zinc