Supramolecular lanthanide assemblies with cucurbit[6]uril: from synthesis and crystal structure to application

Abstract

Reactions between Ln(NO3)3 and cucurbit[6]uril in HNO3 have been studied, aiming to creatie novel light-emitting systems. Aquanitrato complexes of lanthanides were obtained as supramolecular assemblies 1-10 with the organic macrocyclic...

Highly tunable emission properties of solid-state supramolecular compounds based on Eu mixed-lanthanide complexes and cucurbit[6]uril

“…The IR spectra of compounds 1–9 are typical of cucurbit[6]uril-containing compounds 12–15 and are consistent with the findings of structural analysis. The strong and broad stretching band in the 3700–2800 cm −1 region is attributed to the presence of different types of water molecules (for 1–9 ) involved in hydrogen bonding in complexes.…”

“…Types α and β are represented by the lanthanides, Nd–Tb, while type γ corresponds to late lanthanides, Dy–Yb, as reported recently. 14 The heterolanthanide Eu–Ln congeners also follow the categorization into the three types, but they mainly belong to type β, replicating the structure of the Eu compound. More specifically, in the type α and β structures, each Ln( iii ) cation coordinates two O atoms of CB[6], two O atoms of bidentate nitrate anion, and five aqua ligands.…”

“…We have successfully synthesized and characterized nine novel mixed supramolecular lanthanide complexes (compounds 1–9 ). According to single-crystal and powder XRD analysis, they are categorized into three structural types that have recently been described 14 for homolanthanide congeners. Most of the heterolanthanide compounds, namely, 3–8 , belong to structural β type of the pure Eu compound, implying adjustability of the coordination environment of metal ions to replicate the Eu structure.…”

“…These crystalline compounds form one-, two-, or three-dimensional structures from metal ions or clusters coordinated to organic ligands. 12–19 Building blocks of macrocyclic cavitands CB[6] can both generate novel crystal structures and provide a new strategy for creating networks or even frameworks with channels or voids which can provide new opportunities for potential applications. 8,20–27 Conjugation of supramolecular structures with cucurbituril and complexing lanthanide ions is of particular interest.…”