(S)-5-(p-nitrobenzyl)-PCTA, a promising bifunctional ligand with advantageous metal ion complexation kinetics.
A bifunctional version of PCTA (3,6,9,15-tetraazabicyclo[9.3.1]pentadeca-1(15),11,13-triene-3,6,9,-triacetic acid) that exhibits fast complexation kinetics with the trivalent lanthanide(III) ions was synthesized in reasonable yields starting from N,N',N''-tristosyl-(S)-2-(p-nitrobenzyl)-diethylenetriamine. pH-potentiometric studies showed that the basicities of p-nitrobenzyl-PCTA and the parent ligand PCTA were similar. The stability of M(NO(2)-Bn-PCTA) (M = Mg(2+), Ca(2+), Cu(2+), Zn(2+)) complexes was similar to that of the corresponding PCTA complexes, while the stability of Ln(3+) complexes of the bifunctional ligand is somewhat lower than that of PCTA chelates. The rate of complex formation of Ln(NO(2)-Bn-PCTA) complexes was found to be quite similar to that of PCTA, a ligand known to exhibit the fastest formation rates among all lanthanide macrocyclic ligand complexes studied to date. The acid-catalyzed decomplexation kinetic studies of the selected Ln(NO(2)-Bn-PCTA) complexes showed that the kinetic inertness of the complexes was comparable to that of Ln(DOTA) chelates making the bifunctional ligand NO(2)-Bn-PCTA suitable for labeling biological vectors with radioisotopes for nuclear medicine applications.
Tircsó
Gyula
G
Department of Chemistry, University of Texas at Dallas, Richardson, TX 75080, USA.
Benyó
Eniko Tircsóné
ET
Suh
Eul Hyun
EH
Jurek
Paul
P
Kiefer
Garry E
GE
Sherry
A Dean
AD
Kovács
Zoltán
Z
D000085:Acetates / Q000138:chemical synthesis / Q000737:chemistry*; D019086:Bridged Bicyclo Compounds, Heterocyclic / Q000138:chemical synthesis / Q000737:chemistry*; D056831:Coordination Complexes / Q000138:chemical synthesis / Q000737:chemistry*; D007477:Ions / Q000737:chemistry; D007700:Kinetics; D028581:Lanthanoid Series Elements / Q000737:chemistry*; D008024:Ligands; D011199:Potentiometry
C519843:3,6,9,15-tetraazabicyclo(9.3.1)pentadeca-1(15),11,13-triene-3,6,9-triacetic acid; D000085:Acetates; D019086:Bridged Bicyclo Compounds, Heterocyclic; D056831:Coordination Complexes; D007477:Ions; D028581:Lanthanoid Series Elements; D008024:Ligands