TY - JOUR
T1 - Properties of aqueous CeIVDOTA prepared radiolytically and electrochemically in the presence of halide and azide anions
AU - Yardeni, Guy
AU - Popivker, Inna
AU - Meyerstein, Dan
AU - Gitin, Dalia
AU - Maimon, Eric
AU - Zidki, Tomer
AU - Khorosh, Michael
AU - Cohen, Haim
AU - Moisy, Philippe
AU - Pevzner, Svetlana
AU - Zilbermann, Israel
N1 - Publisher Copyright:
© 2024 Elsevier B.V.
PY - 2025/4/1
Y1 - 2025/4/1
N2 - CeIV(DOTA) (1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid) was produced both radiolytically and electrochemically in the presence of halides and azide anions. Only fluoride, the hardest Lewis base studied, ligates to both [CeIII(DOTA)(H2O)]− and CeIV(DOTA), stabilizing the high oxidation state by two orders of magnitude versus [CeIV/III(DOTA)]0/− in its absence. The CeIV(DOTA) complexes are long-lived in the dark (decompose photochemically). The tetravalent complexes decompose mainly via kinetics which obeys a first order rate law. The first step is de-carboxylation of the DOTA ligand followed by the formation of CH2O. The kinetics of oxidation of [CeIII(DOTA)(H2O)]− by Cl2[rad]−, Br2[rad]− and N3[rad] were studied. Cl2[rad]−, the strongest oxidizing agent studied, reacts mainly via H atom abstraction from the DOTA ligand. Br2[rad]− at both acidic and neutral pH oxidizes [CeIII(DOTA)(H2O)]− with rate constants of <3 × 106 M−1s−1, as measured by pulse radiolysis, via an inner sphere mechanism. N3[rad] oxidizes [CeIII(DOTA)(H2O)]− to its tetravalent analogue as well, as proved by UV–vis data after steady-state radiolysis. The presence of F− increased the yield of the CeIV(DOTA) formed. The oxidation rate by N3[rad] is probably lower than that measured for Br2[rad]−.
AB - CeIV(DOTA) (1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid) was produced both radiolytically and electrochemically in the presence of halides and azide anions. Only fluoride, the hardest Lewis base studied, ligates to both [CeIII(DOTA)(H2O)]− and CeIV(DOTA), stabilizing the high oxidation state by two orders of magnitude versus [CeIV/III(DOTA)]0/− in its absence. The CeIV(DOTA) complexes are long-lived in the dark (decompose photochemically). The tetravalent complexes decompose mainly via kinetics which obeys a first order rate law. The first step is de-carboxylation of the DOTA ligand followed by the formation of CH2O. The kinetics of oxidation of [CeIII(DOTA)(H2O)]− by Cl2[rad]−, Br2[rad]− and N3[rad] were studied. Cl2[rad]−, the strongest oxidizing agent studied, reacts mainly via H atom abstraction from the DOTA ligand. Br2[rad]− at both acidic and neutral pH oxidizes [CeIII(DOTA)(H2O)]− with rate constants of <3 × 106 M−1s−1, as measured by pulse radiolysis, via an inner sphere mechanism. N3[rad] oxidizes [CeIII(DOTA)(H2O)]− to its tetravalent analogue as well, as proved by UV–vis data after steady-state radiolysis. The presence of F− increased the yield of the CeIV(DOTA) formed. The oxidation rate by N3[rad] is probably lower than that measured for Br2[rad]−.
UR - http://www.scopus.com/inward/record.url?scp=85215378494&partnerID=8YFLogxK
U2 - 10.1016/j.ica.2024.122521
DO - 10.1016/j.ica.2024.122521
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AN - SCOPUS:85215378494
SN - 0020-1693
VL - 578
JO - Inorganica Chimica Acta
JF - Inorganica Chimica Acta
M1 - 122521
ER -