A p-tert-butylcalix[4]arene functionalised at its lower rim with ether-amide pendant arms acts as an inorganic–organic receptor: structural and photophysical properties of its lanthanide complexes
作者:Flor de Maria Ramírez、Loïc Charbonnière、Gilles Muller、Rosario Scopelliti、Jean-Claude G. Bünzli
DOI:10.1039/b105513p
日期:——
The new narrow-rim functionalised receptor 5,11,17,23-tetra-tert-butyl-25,26,27,28-tetrakis[2-(diethylcarbamoylmethoxy)ethoxy]calix[4]arene (A4bL4) has been synthesised. NMR spectra show it to adopt a cone conformation in solution with a time-averaged C4v symmetry. A4bL4 reacts with trivalent lanthanide ions in acetonitrile to yield 1 â¶ 1 complexes with logK1 in the range 8.6â9.6, as demonstrated by ES-MS, 1H- and 13C-NMR data. Complexes with Ln = Eu, Gd, Tb, and Lu have been isolated and the crystal structure of [Lu(A4bL4)(H2O)](CF3SO3)3·2Et2O shows the metal ion encapsulated in the cavity formed by the four arms. LuIII is 9-co-ordinated, being bound to the four
ether and four carbonyl functions and to a water molecule itself H-bonded to the phenolic ether functions, which rigidifies the cavity formed by the pendant arms. Additionally, an ether molecule is inserted into the hydrophobic cavity defined by the aromatic rings. Both NMR (La, Lu) and luminescence (Eu, Tb) data point to a fairly high local symmetry at the metal centre, while lifetime determinations are consistent with the co-ordination of an inner-sphere water molecule. The new ligand sensitises the luminescence of the TbIII ion (Qabs
= 5.8% in acetonitrile, ÏF
 = 1.42 ms) while the probable presence of a LMCT state severely limits such a process for EuIII: Qabs
= 2.0%, ÏF
 = 0.73 ms.
新的窄边缘功能化受体5,11,17,23-四叔丁基-25,26,27,28-四[(2-(二乙基氨基甲氧基)乙氧基)]大环[4]芳烃(A4bL4)已成功合成。NMR光谱显示其在溶液中呈现锥体构象,具有时间平均的C4v对称性。A4bL4与丙三价铕、镓、铽、铥离子在乙腈中反应,生成1:1的配合物,logK1范围为8.6-9.6,这通过ES-MS、1H-和13C-NMR数据得到了证实。已分离出Ln = Eu、Gd、Tb和Lu的配合物,且[Lu(A4bL4)(H2O)](CF3SO3)3·2Et2O的晶体结构显示金属离子被四个臂形成的腔体包裹。LuIII为9配位状态,连接四个醚基和四个羰基功能团,以及一个通过氢键与酚醚基团相连的水分子,从而固定了由悬臂形成的腔体。此外,一个醚分子被插入定义为芳香环的疏水腔体中。NMR(La, Lu)和光致发光(Eu, Tb)数据均指向金属中心具有相对较高的局部对称性,而寿命测定与内层水分子的配位一致。新配体使得TbIII离子的发光敏感化(Qabs = 5.8%在乙腈中,τF = 1.42 ms),而LMCT状态的可能存在严重限制了EuIII的这种过程:Qabs = 2.0%,τF = 0.73 ms。