Tetraphenylethene-Embedded Pillar[5]arene and [15]Paracyclophane: Distorted Cavities and Host–Guest Binding Properties

Yingtao Fan,Kaitai Hu,Junyi Nan,Yingzhong Shen

doi:10.3390/molecules26195915

Yingtao Fan, Kaitai Hu + Show 2 more

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https://doi.org/10.3390/molecules26195915

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Abstract

Two aggregation-induced emission (AIE) macrocycles (DMP[5]-TPE and PCP[5]-TPE) were prepared by embedding Tetraphenylethene (TPE) unit into the skeletons of Dimethoxypillar[5]arene (DMP[5]) and [15]Paracyclophane ([15]PCP) at meso position, respectively. In crystal, the PCP[5]-TPE showed a distorted cavity, and the incubation of hexane inside the DMP[5]-TPE cavity caused a distinct change in the molecular conformation compared to PCP[5]-TPE. There was no complexation between PCP[5]-TPE and 1,4-dicyanobutane (DCB). UV absorption experiments showed the distorted cavity of DMP[5]-TPE hindered association with DCB.

Highlights

Macrocyclic molecules are the most important supramolecular hosts, with multivalent binding sites and ring-like structures [1]
Pillararenes are new generation macrocyclic molecules, made up of hydroquinone units linked by methylene bridges [2,3,4,5]
Pillararenes show excellent host–guest binding properties, which can recognize ionic guests [6,7], and interact strongly with selective neutral objects [8,9]. [15]Paracyclophane ([15]PCP) received a great deal of attention since the first report by Huang in 2018 [10]. [15]PCP is a new carbon-bridged macrocycle, and its structure is similar to that of pillar[5]arene. [15]PCP can be synthesized by the hydrodeoxygenation of pillar[5]arene via aryl fluorosulfonate intermediates with a high yield

Summary

Introduction

Macrocyclic molecules are the most important supramolecular hosts, with multivalent binding sites and ring-like structures [1]. It is important to explore the host–guest binding properties of the meso position of pillararene. To maintain the lower-energy state of the TPE unit, the skeletons of pillararene are deformed to keep their propeller-like conformation [15]. 2 of 8 2 of 8 of the TPE unit, the skeletons of pillararene are deformed to keep their propeller-like con-

Results

Conclusion