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Equilibrium, Kinetic and Structural Properties of Gallium(III) and Some Divalent Metal Complexes Formed with the New DATA m and DATA 5m Ligands
Author(s) -
Farkas Edit,
Nagel Johannes,
Waldron Bradley P.,
Parker David,
Tóth Imre,
Brücher Ernő,
Rösch Frank,
Baranyai Zsolt
Publication year - 2017
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201701508
Subject(s) - chemistry , dissociation (chemistry) , gallium , chelation , nuclear magnetic resonance spectroscopy , inorganic chemistry , ligand (biochemistry) , stability constants of complexes , equilibrium constant , metal , crystallography , nuclear chemistry , stereochemistry , aqueous solution , organic chemistry , biochemistry , receptor
The development of 68 Ge/ 68 Ga generators has made the positron‐emitting 68 Ga isotope widely accessible and raised interest in new chelate complexes of Ga 3+ . The hexadentate 1,4‐di(acetate)‐6‐methyl[amino(methyl)acetate]perhydro‐1,4‐diazepane (DATA m ) ligand and its bifunctional analogue, 1,4‐di(acetate)‐6‐pentanoic acid[amino(methyl)acetate]perhydro‐1,4‐diazepane (DATA 5m ), rapidly form complexes with 68 Ga in high radiochemical yield. The stability constants of DATA m and DATA 5m complexes formed with Ga 3+ , Zn 2+ , Cu 2+ , Mn 2+ and Ca 2+ have been determined by using pH potentiometry, spectrophotometry (Cu 2+ ) and 1 H and 71 Ga NMR spectroscopy (Ga 3+ ). The stability constants of Ga(DATA m ) and Ga(DATA 5m ) complexes are slightly higher than those of Ga(AAZTA). The species distribution calculations indicated the predominance of Ga(L)OH mixed‐hydroxo complexes at physiological pH. The 1 H and 71 Ga NMR spectroscopy studies provided information about the coordinated functional groups of ligands and on the kinetics of exchange between the Ga(L) and Ga(L)OH complexes. The transmetalation reactions between the Ga(L) complexes and Cu 2+ citrate (6