A study on the coordination of cyclohexanocucurbit[6]uril with copper, zinc, and magnesium ions

Jun Zheng,Yanmei Jin,Jie Gao,Xinan Yang,Lin Zhang,Peihua Ma

doi:10.1515/gps-2021-0074

Abstract

Abstract Herein, we report the supramolecular complexes of cyclohexanocucurbit[6]uril (CyH6Q[6]) with Cu(ClO4)2, Zn(ClO4)2, and Mg(ClO4)2 in formic acid solution. The crystal structure was determined using single crystal X-ray diffraction. The analysis results showed that CyH6Q [6] formed a one-dimensional supramolecular chain with Cu(ClO4)2 and formed a supramolecular assembly with a mixture ratio of 2:3 with Zn(ClO4)2 and Mg(ClO4)2. In this system, ClO 4 − {\text{ClO}}_{4}^{-} induced CyH6Q[6] and metal ions to form supramolecular complexes through ion–dipole interactions.

Highlights

Cucurbit[n]uril [1,2,3,4,5,6,7,8,9,10,11,12,13] is the fourth generation of macrocyclic compounds after cyclodextrin, crown ether, and calixarene
One central Cu2+ ion of the complex was coordinated by one carbonyl oxygen atom (O1) and two water molecules (O1W and O2W) from the ligand CyH6Q[6] molecule
The coordination bond lengths of Cu1–O1W and Cu1–O2W were 1.975 and 1.978 Å, respectively. Another central Cu2+ ion of the complex was coordinated by one carbonyl oxygen atom (O7) and two water molecules (O3W and O4W) from the ligand CyH6Q[6] molecule

Summary

Introduction

Cucurbit[n]uril [1,2,3,4,5,6,7,8,9,10,11,12,13] is the fourth generation of macrocyclic compounds after cyclodextrin, crown ether, and calixarene. In the Key Laboratory of Macrocyclic and Supramolecular Chemistry of Guizhou Province, a series of Ln–CyH5Q[5] complexes formed by the interaction of fully substituted cyclohexyl cucurbit[5]uril with rare earth metal ions has been reported [28]. A series of Ln–CyH6Q[6] complexes formed by the interaction of fully substituted cyclohexyl cucurbit[6]uril with rare earth metal ions has been reported [29]. CyH6Q[6] (Figure 1) was used as the ligand with Cu(ClO4), Zn(ClO4), and Mg(ClO4) to construct three kinds of supramolecular complexes in formic acid solution. Their structures were determined using single crystal X-ray diffraction.

Experimental

Preparation of complexes

Instrument characterization methods and test conditions

Description of the crystal structure of complexes 1–3

Conclusion