TriQuinoline

Shinya Adachi,Masakatsu Shibasaki,Naoya Kumagai

doi:10.1038/s41467-019-11818-1

TriQuinoline

Shinya Adachi, Masakatsu Shibasaki + Show 1 more

Open Access

https://doi.org/10.1038/s41467-019-11818-1

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Journal: Nature Communications	Publication Date: Aug 23, 2019
Citations: 25	License type: open-access

Affiliation: Microbial Chemistry Research Foundation

Abstract

The bottom-up synthesis of structurally well-defined motifs of graphitic materials is crucial to understanding their physicochemical properties and to elicit new functions. Herein, we report the design and synthesis of TriQuinoline (TQ) as a molecular model for pyridinic-nitrogen defects in graphene sheets. TQ is a trimer of quinoline units concatenated at the 2- and 8-positions in a head-to-tail fashion, whose structure leads to unusual aromatisation behaviour at the final stage of the synthesis. The central atomic-sized void endows TQ with high proton affinity, which was confirmed empirically and computationally. TQ•H+ is a two-dimensional cationic molecule that displays both π–π and CH–π contact modes, culminating in the formation of the ternary complex ([12]cycloparaphenylene(CPP) ⊃ (TQ•H+/coronene)) that consists of TQ•H+, coronene (flat), and [12]cycloparaphenylene ([12]CPP) (ring). The water-miscibility of TQ•H+ allows it to serve as an efficient DNA intercalator for e.g. the inhibition of topoisomerase I activity.

Highlights

The bottom-up synthesis of structurally well-defined motifs of graphitic materials is crucial to understanding their physicochemical properties and to elicit new functions
Various methods have emerged for the preparation of graphitic materials with structural defects surrounded by three pyridinic nitrogens22–24, paving the way for the introduction of metal cations to impart, e.g., particular catalytic functionality25,26 with prospective applications in energy conversion27 and biocompatible catalysis28
The atomic-size void located at the centre of the rigid 2D TQ scaffold displays remarkably high proton affinity, which in turn endows the molecule with water miscibility and the ability to engage in directional complexation with other graphitic materials via π–π and CH–π interactions

Summary

Introduction

The bottom-up synthesis of structurally well-defined motifs of graphitic materials is crucial to understanding their physicochemical properties and to elicit new functions. The rapidly growing applications of graphitic materials and polyaromatic hydrocarbons (PAHs) are spurring research on exotic polyaromatic molecules that feature skewed and non-flat three-dimensional (3D) architectures (Fig. 1a). The rapidly growing applications of graphitic materials and polyaromatic hydrocarbons (PAHs) are spurring research on exotic polyaromatic molecules that feature skewed and non-flat three-dimensional (3D) architectures (Fig. 1a)2–13 Another area of intense research is the modification of the physicochemical properties of PAHs by strategic doping with heteroatoms. We were interested in a bottom-up and structurally defined synthesis of miniaturised graphitic-nitrogen sites that feature an inherent atomic-sized void that may potentially display the characteristic physicochemical properties of small molecules amenable to a variety of spectroscopic analysis techniques. The atomic-size void located at the centre of the rigid 2D TQ scaffold displays remarkably high proton affinity, which in turn endows the molecule with water miscibility and the ability to engage in directional complexation with other graphitic materials via π (cation)–π and CH–π interactions

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Conclusion