title: New tris-3,4-HOPO lanthanide complexes as potential imaging probes: complex stability and magnetic properties.
abstract: There is a growing interest in the development of new medical diagnostic tools with higher sensibility and less damage for the patient body, namely on imaging reporters for the management of diseases and optimization of treatment strategies. This article examines the properties of a new class of lanthanide complexes with a tripodal tris-3-hydroxy-4-pyridinone (tris-3,4-HOPO) ligand - NTP(PrHP)(3). Among the studies herein performed, major relevance is given to the thermodynamic stability of the complexes with a series of Ln(3+) ions (Ln = La, Pr, Gd, Er, Lu) and to the magnetic relaxation properties of the Gd(3+) complex. This hexadentate ligand enables the formation of (1 : 1) Ln(3+) complexes with high thermodynamic stability following the usual trend, while the Gd-chelates show improved relaxivity (higher hydration number), as compared with the commercially available Gd-based contrast agents (CAs); transmetallation of the Gd(3+)-L complex with Zn(2+) proved to be thermodynamically and kinetically disfavored. Therefore, NTP(PrHP)(3) emerges as part of a recently proposed new generation of CAs with prospective imaging sensibility gains.
authors.affiliation: Centro de Química Estrutural, Instituto Superior Técnico, Universidade Técnica de Lisboa, Av. Rovisco Pais 1, 1049-001 Lisboa, Portugal.
authors.forename: Ana C
authors.initials: AC
authors.lastname: Mendonça
authors.forename: André F
authors.initials: AF
authors.lastname: Martins
authors.forename: Andrea
authors.initials: A
authors.lastname: Melchior
authors.forename: Sérgio M
authors.initials: SM
authors.lastname: Marques
authors.forename: Sílvia
authors.initials: S
authors.lastname: Chaves
authors.forename: Sandrine
authors.initials: S
authors.lastname: Villette
authors.forename: Stéphane
authors.initials: S
authors.lastname: Petoud
authors.forename: Pier Luigi
authors.initials: PL
authors.lastname: Zanonato
authors.forename: Marilena
authors.initials: M
authors.lastname: Tolazzi
authors.forename: Célia S
authors.initials: CS
authors.lastname: Bonnet
authors.forename: Éva
authors.initials: É
authors.lastname: Tóth
authors.forename: Plinio
authors.initials: P
authors.lastname: Di Bernardo
authors.forename: Carlos F G C
authors.initials: CF
authors.lastname: Geraldes
authors.forename: M Amélia
authors.initials: MA
authors.lastname: Santos
mesh_terms: D003287:Contrast Media / Q000138:chemical synthesis* / Q000737:chemistry; D056831:Coordination Complexes / Q000138:chemical synthesis / Q000737:chemistry*; D003952:Diagnostic Imaging; D005682:Gadolinium / Q000737:chemistry; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D028581:Lanthanoid Series Elements / Q000737:chemistry*; D008024:Ligands; D008280:Magnetics; D011728:Pyridones / Q000737:chemistry*; D013816:Thermodynamics
chemical_list: D003287:Contrast Media; D056831:Coordination Complexes; D028581:Lanthanoid Series Elements; D008024:Ligands; D011728:Pyridones; D005682:Gadolinium