Cucurbituril as a New Macrocyclic Ligand for Complexation of Lanthanide Cations in Aqueous Solutions

Abstract

6 ·26H 2 O (7) were obtained in high yield by reaction of cucurbituril with aqueous solutions of lanthanide(III) species. The crystal structures of the compounds show a packing of 1:1, 2:2, and 2:3 in the (cucurbituril)lanthanide [a]

Chlorine Anion Encapsulation by Molecular Capsules Based on Cucurbit[5]uril and Decamethylcucurbit[5]uril

“…Decamethylcucurbit [5]uril (Me 10 Q [5]) was the first fully substituted Q[n] discovered in 1992 by Stoddart and co-workers [19]. The novel structure and the capability of forming complexes with molecules and ions make the cucurbit[n]uril family attractive, not only as synthetic receptors but also as building blocks for supramolecular assemblies such as rotaxanes, catenanes, and molecular machines [24][25][26][27][28][29][30]. Nevertheless research on Q[n]s as receptors for anions is scarce [17,31].…”

Sc(III), Eu(III), and Gd(III) Complexes with Macrocyclic Cavitand Cucurbit[6]uril: Synthesis and Crystal Structures

“…Complexes I and II are isostructural to one another (to an accuracy of the crystallization water molecules) and the previously synthesized gadolinium, holmium, and ytterbium complexes with cucurbit [6]uril [8]. The metal : cucurbit [6]uril ratio in these complexes is 1 : 1.…”

“…cucurbit [6]uril was found to be efficient as a polydentate ligand used in isolation of the kinetically labile lanthanide(III) complexes from aqueous solutions [8][9][10]. The lanthanide complexes are known to show interesting spectral and magnetic properties.…”

“…Cucurbit [6]uril is similar to 18-crown-6 in size, but has a higher negative charge on the donor O atoms of portals, which makes its compounds with the metal cations more stable. Previously, we synthesized and studied the structures of its complexes with L ‡ 3+ , Ce 3+ , Sm 3+ , Gd 3+ , Ho 3+ , Yb 3+ with the metal : cucurbit [6]uril ratios 1 : 1, 2 : 2, and 2 : 3 [8], where the cucurbit [6]uril molecule is coordinated by the lanthanide cations through the O atoms of portals in bi-or tetradentate mode. The yttrium complex with cucurbit [6]…”

One-Dimensional Coordination Polymers of Lanthanide Cations to Cucurbit[7]uril Built Using a Range of Tetrachloride Transition-Metal Dianion Structure Inducers

“…Cucurbit[n]urils(Q[n]s) [9][10][11][12][13][14] consist of a rigid hydrophobic cavity of low polarity, accessible through two open polar portals rimmed with carbonyl groups, which can interact with various metal ions [15][16][17][18][19][20][21][22][23][24][25][26], or their complexes [27][28][29][30][31][32][33][34][35][36][37][38][39][40] or clusters [41][42][43][44][45][46][47][48][49][50] [53]. In recent years, there has been a trend towards introducing an organic or inorganic species into the metal-Q[n] systems as a "structure inducer" or trigger, since the properties, structural novelties, and functionalities of the resulting coordination polymers have often exceeded those observed in the absence of such agents.…”