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Published on: August 23, 2018
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Redox-switchable host-guest complexes of metallocenes and [8]cycloparaphenylene
Hyejin Kwon1, Brian S Newell2, Carson J Bruns1,3
1Department of Mechanical Engineering, University of Colorado Boulder, 1111 Engineering Drive, 427 UCB, Boulder, CO 80309, USA.
Nanoscale
|September 22, 2022
Summary
Cycloparaphenylenes ([8]CPP) can host metallocene guests via CH-π interactions, enhancing stability through redox changes or hydrogen bonding. These [8]CPP-metallocene complexes offer new building blocks for nanoelectronics.
Area of Science:
- Supramolecular Chemistry
- Organic Nanomaterials
- Host-Guest Chemistry
Background:
- Cycloparaphenylenes (CPPs) are macrocyclic organic semiconductors with tunable optoelectronic properties.
- CPPs can form host-guest complexes, primarily stabilized by π-π interactions with fullerenes.
- Aromatic CH-π interactions are also known to stabilize CPP-polycyclic guest complexes.
Purpose of the Study:
- To investigate the use of CH-π interactions for hosting redox-active metallocene guests within [8]cycloparaphenylene ([8]CPP).
- To explore how guest oxidation and functionalization affect the stability and structure of CPP-metallocene complexes.
- To demonstrate the potential of [8]CPP-metallocene complexes in nanoelectronics and molecular machines.
Main Methods:
- Experimental synthesis and characterization of host-guest complexes.
- Computational modeling to understand binding interactions and properties.
- Crystallographic analysis of solid-state structures.
- Electrochemical studies to probe redox behavior.
Main Results:
- [8]CPP successfully hosts metallocene guests (ferrocene and cobaltocenium) primarily through CH-π interactions.
- Metallocene guest oxidation increases binding affinity and alters complex geometry.
- Functionalization of guests with oxygen-bearing side chains enhances stability via CH-O hydrogen bonds.
- Crystallography confirmed CH-π interactions in ferrocene complexes and additional π-π interactions in cobaltocenium complexes.
Conclusions:
- CH-π bonding is a versatile driving force for CPP host-guest complex formation, complementing other supramolecular interactions.
- [8]CPP-metallocene complexes exhibit tunable stability and redox-dependent behavior.
- These complexes represent promising synthons for advanced nanoelectronic devices and molecular machines.
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