STABILITIES OF THE FE(III), GA(III) AND IN(III) CHELATES OF N,N',N''-TRIAZACYCLONONANETRIACETIC ACID
STABILITIES OF THE FE(III), GA(III) AND IN(III) CHELATES OF N,N',N''-TRIAZACYCLONONANETRIACETIC ACID
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DOI：
10.1016/s0020-1693(00)86821-8
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发表时间：
1991-03-15
影响因子：
2.8
通讯作者：
MARTELL, AE
中科院分区：
文献类型：
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作者：
CLARKE, ET;MARTELL, AE
测定了Fe（III）、Ga（III）和In（III）离子与六齿大环配体1,4,7-三氮环烷-N，N′，N′-三乙酸（NOTA）配合物在KCl负载电解质（0.100 M）中25.0℃下的稳定性常数。Ga（III）和Fe（III）与NOTA配合物的稳定性常数K(ML) = [ML]/[L3-][M3+]，分别为10（30.98）和10(28.3)，表明这些小金属离子与NOTA有优先相互作用。In(III)-NOTA配合物的稳定常数稍低（10(26.2)）。物种分布曲线显示了Ga（III）和In（III）螯合物在p[H] 9.3和6.5时分别转化为单羟基形式。Fe(III)-NOTA配合物在p[H] 7.5及以上解离形成氢氧化铁，而羟基In(III)-NOTA配合物在p[H] 7.5及以上转化为氢氧化铟。Ga(III)-NOTA体系在所有p[H]值下都是可溶的，这是由于羟基络合物在p[H] 10.4及以上时转化为四羟基没食子酸盐离子的结果。
The stability constants of the complexes of Fe(III), Ga(III) and In(III) ions with the sexadentate macrocyclic ligand 1,4,7-triazacyclonane-N,N',N"-triacetic acid (NOTA) have been determined in KCl supporting electrolyte (0.100 M) at 25.0-degrees-C. The stability constants (K(ML) = [ML]/[L3-][M3+] of the Ga(III) and Fe(III) complexes with NOTA are high, 10(30.98) and 10(28.3), respectively, and indicate preferential interaction of these small metal ions with NOTA. The stability constant of the In(III)-NOTA complex is somewhat lower (10(26.2)). Species distribution curves are presented to illustrate the conversion of the Ga(III) and In(III) chelates to the monohydroxo forms at p[H] 9.3 and 6.5, respectively. The Fe(III)-NOTA complex dissociates to form ferric hydroxide at and above p[H] 7.5, while the hydroxo In(III)-NOTA complex is converted to indium hydroxide at and above p[H] 7.5. The Ga(III)-NOTA system is soluble at all p[H] values, as a consequence of conversion of the hydroxo complex to the tetrahydroxo gallate ion at p[H] 10.4 and above.