铅离子与镉离子高选择性的大环化合物:对称四甲基六元瓜环与过渡金属及重金属离子的配合作用(英文)

Highly Selective Compounds for Lead and Cadmium: Complexation of α,α′,δ,δ′-Tetramethylcucurbit[6]uril with Transition-Metal and Heavy-Metal Ions

利用微分脉冲伏安法研究了对称四甲基六元瓜环(TMeQ[6])与过渡金属的相互作用。结果表明该主体大环化合物对Pb2+和Cd2+离子具有较好的选择性作用。伏安数据测定表明Pb2+及Cd2+离子与对称四甲基六元瓜环以nM2+/nTMeQ[6]=2配位,其配合平衡常数分别为(KPb2+=2.12×109L2·mol-2,KCa2+=2.10×109L2·mol-2)。Pb2+离子与TMeQ[6]的晶体结构进一步证实了上述实验结果。

The complexation of α,α＇δ,δ＇-tetramethylcucurbit[6]nril （TMeQ[6]） complexes with transition-metal ions was studied by differential pulse vohammetry （DPV）. The results reveal that this water-soluble cage-type compound shows very high selectivity for Pb^2＋ and Cd^2＋, while it is a masking compound for other transition-metal ions, particularly for Fe^3＋, Co^2＋, Zn^2＋, and Cr3＋, due to a sharp decrease in the DPV peak current of these metal ions in the presence of TMeQ[6]. Binding constants were determined from vohammetric data. The Pb2＋ and Cd2＋ cations display a high binding affinity for TMeQ[6] （Kpb2＋=2.12×10^9 L2·mo1-2, Kca2＋=2.10×10^9 L2·mo1-2） and form 2：1 nM2＋/nTMeQ[6] complexes. The crystal structure of TMeQ[6]-Pb^2＋ indicates a 2：1 （nPb2＋/nTMeQ[6]） complex in the solid state, which is consistent with the results in solution. CCDC： 723280.