A Study on the Coordination of Fully Substituted Cyclopentano Cucurbit[5, 6]uril with Copper and Zinc Ions

Manipulating the Host-Guest Chemistry of Cucurbituril to Propel Highly Reversible Zinc Metal Anodes

Rechargeable aqueous zinc-ion batteries are practically plagued by the short lifespan and low Coulombic efficiency (CE) of Zn anodes resulting from random dendrite deposition and parasitic reactions. Herein, the host-guest chemistry of cucurbituril additive with Zn2+ to achieve longstanding Zn anodes is manipulated. The macrocyclic molecule of cucurbit[5]uril (CB[5]) is delicately designed to reconstruct both the CB[5]-adsorbed electric-double layer (EDL) structure at the Zn interface and the hydrated sheath of Zn2+ ions. Especially benefiting from the desirable carbonyl rims and suitable hydrophobic cavities, the CB[5] has a strong host-guest interaction with Zn2+ ions, which exclusively permits rapid Zn2+ flux across the EDL interface but retards the H2 O radicals and SO4 2- . Accordingly, such a unique particle redistributor warrants long-lasting dendrite-free deposition by homogenizing Zn nucleation/growth and significantly improved CE by inhibiting side reactions. The Zn anode can deliver superior reversibility in CB[5]-containing electrolyte with a ninefold increase of cycle lifetime and an elevated CE of 99.7% under harsh test conditions (10 mA cm-2 /10 mA h cm-2 ). The work opens a new avenue from the perspective of host-guest chemistry to propel the development of rechargeable Zn metal batteries and beyond.

Study on the coordination of cyclopentanocucurbit[5,6]uril with Fe3+, Co2+ and Ni2+ ions

This paper reports the coordination of cyclopentanocucurbit[5]uril (CyP5Q[5]) and cyclopentanocucurbit[6]uril (CyP6Q[6]) with Fe(ClO4)3, Co(ClO4)2 and Ni(ClO4)2. Single crystal X-ray diffraction analysis shows the metal ions are directly coordinated with the portal of the cucurbit[n]uril to form a one-dimensional supramolecular chain or independent systems in the CyP5Q[5]@Fe(ClO4)3, CyP5Q[5]@Co(ClO4)2, CyP6Q[6]@Co(ClO4)2 and CyP5Q[5]@Ni(ClO4)2 complexes. In CyP6Q[6]@Fe(ClO4)3, the metal ion is not directly coordinated with the cucurbit[n]uril portal, but after forming Fe(H2O)6, it interacts with the cucurbit[n]uril portal via a hydrogen bond. The CyP6Q[6]@Ni(ClO4)2 complex is quite special; in this system, there are both metal ions directly coordinated with the cucurbit[n]uril portal and free on the outer surface of the cucurbit[n]uril.

Preparation and characterization of a new type of symmetrical dicyclopentyl substituted cucurbit[6]uril

A symmetrical dicyclopentyl substituted cucurbit[6]uril (CyP2Q[6]) was synthesized, and crystallized under the conditions of 3 mol/L hydrochloric acid solution and the induction of ZnCl2. The crystal structure was characterized by X-ray single crystal diffractometer, 1H NMR and MS, and the results show that the crystal belongs to the monoclinic crystal system with P21/n space group, a = 13.095 (2), b = 33.002 (6), c = 15.770 (3), α = 90°, β = 102.828(5)°, γ = 90°, Z = 4, and a macroporous honeycomb structure appears in the crystal.

Host-guest modes and supramolecular frameworks of complexes of tetramethyl cucurbit[6]uril with 4-chloroaniline and 4,4'-diaminostilbene

Since the first reportal on decamethylcucurbit[5]uril (Me₁₀Q[5]) in 1992, substituted cucurbit[n]urils have attracted considerable research interest. In this study, the host–guest modes between the tetramethyl cucurbit[6]uril (TMeQ[6]) as a host and 4-chloroaniline and 4,4′-diaminostilbene (G1 and G2) as guests were investigated by single-crystal X-ray diffraction, NMR, ITC, UV-Vis spectrum, and MALDI-TOF mass spectrometry analyses. The experimental results showed that TMeQ[6] formed a 1 : 1 inclusion compound with G1, and the carbonyl portal of TMeQ[6] formed a 1 : 1 self-assembly with G2. Further, multi-dimensional supramolecular frameworks were formed driven by weak interaction forces in the system (hydrogen bonding, C–H⋯π interactions, ion–dipole interactions, and dipole–dipole interactions).

Two TMeQ[6]-based multi-dimensional supramolecular frameworks were formed driven by weak interaction forces in the system (hydrogen bonding, C–H... π interactions, ion–dipole interactions, and dipole–dipole interactions).

Supramolecular chemistry of substituted cucurbit[n]urils

This review covers important advances in the field of substituted cucurbit[n]urils.