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ISSN 0253-2964(Print)
ISSN 1229-5949(Online)
Volume 18, Number 11
BKCSDE 18(11)
November 20, 1997 |
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Title |
Stability Studies of Divalent and Trivalent Metal Complexes with 1,7,13-Trioxa-4,10,16-triazacyclooctadecane-N,N',N |
Author |
Choonpyo Hong*, Dong Won Kim, Ki-Young Choi |
Keywords |
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Abstract |
The potentiometric methods have been used to determined the protonation constants (logKiH) for the synthesized 1,7,13-trioxa-4,10,16-triazacyclooctadecane-N,N',N ''-tri(methylacetic acid) [N3O3-tri(methylacetic acid)] and the stability constants (logKML) of the complexes of divalent and trivalent metal ions with the ligand N3O3-tri(methylacetic acid). The protonation constants of N3O3-tri(methylacetic acid) were 9.70 for logK1H, 9.18 for logK2H, 7.27 for logK3H, 3.38 for logK4H, and 2.94 for logK5H. The stability constants for the complexes of divalent metal ions with N3O3-tri(methylacetic acid) were 10.39 for Co2+, 10.68 for Ni2+, 13.45 for Cu2+, and 13.00 for Zn2+. The order of the stability constants for the complexes of the divalent metal ions with N3O3-tri(methylacetic acid) was Co2+ < Ni2+ < Zn2+ < Cu2+. The stability constants for the complexes of trivalent metal ions with N3O3-tri(methylacetic acid) were 16.20 for Ce3+, 16.40 for Eu3+, 16.27 for Gd3+, and 15.80 for Yb3+. The results obtained in this study were compared to those obtained for similar ligands, 1,7-dioxa-4,10,13-triazacyclopentadecane-N,N',N"-t ri(methylacetic acid) and 1,7,13-trioxa-4,10,16-triazacyclooctadecane-N,N',N "-triacetic acid, which have been previously reported. |
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1158 - 1161 |
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