Noncovalent Modification of Cycloparaphenylene by Catenane Formation Using an Active Metal Template Strategy**

Abstract

The active metal template (AMT) strategy is a powerful tool for the formation of mechanically interlocked molecules (MIMs) such as rotaxanes and catenanes, allowing the synthesis of a variety of MIMs, including π‐conjugated and multicomponent macrocycles. Cycloparaphenylene (CPP) is an emerging molecule characterized by its cyclic π‐conjugated structure and unique properties. Therefore, diverse modifications of CPPs are expected for its wide application. However, most CPP modifications require early‐stage functionalization and the direct modification of CPPs is very limited. Herein, we report the synthesis of a catenane consisting of [9]CPP and a 2,2´‐bipyridine macrocycle as a new CPP analogue that contains a reliable synthetic scaffold enabling diverse and concise post‐modification. Following the AMT strategy, [9]CPP–bipyridine catenane was successfully synthesized through Ni‐mediated aryl–aryl coupling. Catalytic C–H borylation/cross‐coupling and metal complexation at bipyridine macrocycle moiety, an effective post‐functionalization method, were also demonstrated with [9]CPP–bipyridine catenane. Single crystal X‐ray structural analysis revealed that the [9]CPP–bipyridine catenane forms a tridentated complex with an Ag ion inside the CPP ring. This interaction significantly enhances phosphorescence lifetime through improved intermolecular interactions.

Cycloparaphenylene-based [2]catenanes: interlocking the carbon nanohoops

“…Notably, as recently demonstrated by Jasti et al , 10 c the AMT approach has already shown its great power in the synthesis of interlocked nanocarbons. 14 Recently, by using a commonly-used 2, 2′-bipyridine macrocycle ligand 10 for the AMT approach, Itami et al 15 successfully synthesized the [2]catenane 14 with [9]CPP as the other macrocyclic component.…”

A High‐Yielding Active Template Click Reaction (AT−CuAAC) for the Synthesis of Mechanically Interlocked Nanohoops

“…rotaxanes, catenanes, and knots) providing an opportunity to interrogate the effects of topological manipulation on the properties of these molecular nanocarbons. [9][10][11][12][13][14][15][16][17][18][19][20][21][22][23] While methods using passive metal templates, [9] supramolecular assemblies, [10][11][12][13] or covalent tethering groups [14][15][16] have proven successful, the active template (AT) strategy offers an attractive approach for the selective synthesis of asymmetrical structures via kinetically driven reactions. [18][19][20][21][22][23] Here, we show that a macrocyclic precursor to 2,2'-bipyridyl embedded [9]CPP (bipy [9]CPP) participates in the AT Cu-catalyzed azidealkyne cycloaddition (ATÀ CuAAC) reaction.…”

“…[9][10][11][12][13][14][15][16][17][18][19][20][21][22][23] While methods using passive metal templates, [9] supramolecular assemblies, [10][11][12][13] or covalent tethering groups [14][15][16] have proven successful, the active template (AT) strategy offers an attractive approach for the selective synthesis of asymmetrical structures via kinetically driven reactions. [18][19][20][21][22][23] Here, we show that a macrocyclic precursor to 2,2'-bipyridyl embedded [9]CPP (bipy [9]CPP) participates in the AT Cu-catalyzed azidealkyne cycloaddition (ATÀ CuAAC) reaction. With the appropriate design of the macrocyclic ligand, quantitative conversion to [2]rotaxanes could be achieved which then serve as intermediates to nanohoop [2]catenanes (Figure 1).…”