CEA, IRAMIS, UMR 3299 CEA/CNRS, SIS2M, LCCEf, Bât. 125, 91191 Gif-sur-Yvette, France.
Inorg Chem. 2010 Oct 4;49(19):9078-85. doi: 10.1021/ic101396a.
The reaction of rare-earth nitrates with iminodiacetic acid (H(2)IDA) in the presence of cucurbit[6]uril (CB6) in water at room temperature yields a family of isomorphous complexes, M(H(2)IDA)(NO(3))(H(2)O)(6)(2)·CB6·14H(2)O with M = Y (1), Ce (2), Nd (3), Eu (4), Dy (5), Er (6), Tm (7), and Yb (8). In these compounds, the trivalent metal ion is bound to one nitrate ion, six water molecules, and one zwitterionic H(2)IDA molecule. The latter is further partly included in the CB6 cavity, with the ammonium group forming two hydrogen bonds with oxygen atoms of one portal. The uncoordinated carboxylic group is thus encapsulated in CB6 and hydrogen-bonded to the other portal via a water molecule. CB6 is a second-sphere ligand in these complexes, but direct bonding of the metal ion to CB6 can be enforced by using a ligand more deeply imbedded in the cavity, such as 2-pyridylacetate (PA) in Eu(PA)(CB6)(NO(3))(H(2)O)(5)·10H(2)O (11). When the reaction with H(2)IDA is performed with Lu(III) or Cu(II), no metal complex is isolated, but the inclusion compounds (H(3)IDA)(2)(CB6)(2)·xH(2)O with x = 6 (9) or 8 (10) are obtained instead, in which the two H(3)IDA(+) cations are attached to the CB6 portals by ammonium-carbonyl hydrogen bonds and are linked to one another inside the cavity by hydrogen bonding between the carboxylic groups. These complexes are compared to that comprising a dicarboxylic acid devoid of an ammonium functionality, [(H(2)AZ)(CB6)]·6H(2)O (12), where H(2)AZ is azelaic acid. The metal ion complexes 1-8 and the organic complexes 9 and 10 display the unprecedented feature of inclusion of carboxylic groups inside the CB6 cavity, with the CB6/acid stoichiometry and the finer details of the host-guest interactions being dependent on the presence of the metal ion.
在水相中，室温下，用 1,4,7,10-四氮杂环十二烷-1,4,7,10-四乙酸（H(2)IDA）与硝酸镧反应，生成了一系列同晶的配合物，M(H(2)IDA)(NO(3))(H(2)O)(6)(2)·CB6·14H(2)O（其中 M = Y（1），Ce（2），Nd（3），Eu（4），Dy（5），Er（6），Tm（7），和 Yb（8））。在这些化合物中，三价金属离子与一个硝酸根离子、六个水分子和一个两性离子 H(2)IDA 配位。后者部分进入 CB6 内腔，铵基与一个端口的两个氧原子形成氢键。未配位的羧酸基因此被包封在 CB6 中，并通过一个水分子与另一个端口氢键相连。在这些配合物中，CB6 是一个第二配位层的配体，但通过使用更深地嵌入内腔的配体，如 2-吡啶乙酸（PA），可以强制金属离子与 CB6 直接键合，如Eu(PA)(CB6)(NO(3))(H(2)O)(5)·10H(2)O（11）。当用 Lu(III)或 Cu(II)与 H(2)IDA 反应时，没有分离出金属配合物，而是得到了包含化合物(H(3)IDA)(2)(CB6)(2)·xH(2)O（其中 x = 6（9）或 8（10）），其中两个 H(3)IDA(+)阳离子通过铵羰基氢键与 CB6 端口连接，并通过羧酸基团之间的氢键在腔体内相互连接。这些配合物与包含缺乏铵官能团的二羧酸的配合物[(H(2)AZ)(CB6)]·6H(2)O（12）进行了比较，其中 H(2)AZ 是壬二酸。金属离子配合物 1-8 和有机配合物 9 和 10 显示了羧酸基团被包封在 CB6 内腔中的前所未有的特征，CB6/酸的化学计量和主客体相互作用的细节取决于金属离子的存在。
