High stability constants for multivalent metal ion complexes of crown ether derivatives incorporating two spirobenzopyran moieties
High stability constants for multivalent metal ion complexes of crown ether derivatives incorporating two spirobenzopyran moieties
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DOI：
10.1039/b111016k
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发表时间：
2002-01-01
影响因子：
3.3
通讯作者：
Kimura, K
中科院分区：
文献类型：
--
作者：
Nakamura, M;Fujioka, T;Kimura, K
研究了具有两个螺苯并吡喃结构的二氮杂冠醚衍生物在黑暗条件下与金属离子的络合行为。在二氮杂冠醚中引入两个螺苯并吡喃结构部分，沿着异构化为相应的二氮杂冠醚形式，导致了有趣的金属离子络合能力。观察到的对多价金属离子的极高亲和力是由于两种酚盐阴离子与多价金属离子之间的离子相互作用。这一发现得到了吸收光谱测量和电喷雾电离质谱的支持。首次用质谱法测定了在黑暗条件下甲醇中与各种金属离子形成络合物的稳定常数。结果表明，高电荷密度金属离子与双螺苯并吡喃冠醚配合物的稳定常数远大于其母体冠醚环。具体地，带有两个螺苯并吡喃部分的二氮杂-18-冠-6衍生物的La 3+络合物在甲醇中具有大于10（11）M-1的非常高的稳定常数。
The metal ion complexing behavior of diazacrown ether derivatives possessing two spirobenzopyran moieties has been studied under dark conditions. Introduction of two spirobenzopyran moieties into diazacrown ethers resulted in interesting metal ion complexation abilities, along with isomerization of the spirobenzopyran moieties to the corresponding merocyanine form. The extremely high affinity for multivalent metal ions observed is due to an ionic interaction between the two phenolate anions and the multivalent metal ion. This finding is supported by absorption spectral measurements and electrospray ionization mass spectrometry. Stability constants for complex formation with various metal ions in methanol under dark conditions have been determined for the first time using mass spectrometry. It was found that the stability constants for crowned bis(spirobenzopyran) complexes with high charge density metal ions are much greater than those for the parent crown ether rings. Specifically, the La3+ complex of the diaza-18-crown-6 derivative carrying two spirobenzopyran moieties possesses an extraordinarily high stability constant of greater than 10(11) M-1 in methanol.