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Published on: October 10, 2013
Putting ammonia into a chemically opened fullerene
Keith E Whitener1, Michael Frunzi, Sho-ichi Iwamatsu
1Department of Chemistry, Yale University, P.O. Box 208107, New Haven, Connecticut 06520-8107, USA.
Journal of the American Chemical Society
|September 27, 2008
Summary
Researchers encapsulated ammonia (NH3) within an open-cage fullerene. NMR and mass spectrometry confirmed NH3 inclusion, but it slowly escaped over six months, indicating limited stability.
Area of Science:
- Supramolecular Chemistry
- Nanomaterials Science
- Physical Chemistry
Background:
- Fullerenes are carbon-based nanomaterials with unique cage-like structures.
- Open-cage fullerenes offer potential for molecular encapsulation.
- Ammonia (NH3) is a fundamental chemical species with various applications.
Purpose of the Study:
- To investigate the encapsulation of ammonia within a specific open-cage fullerene.
- To characterize the properties and stability of the resulting fullerene-ammonia complex.
- To determine the incorporation fraction and long-term retention of ammonia.
Main Methods:
- Synthesis of an open-cage fullerene with a 20-membered ring orifice.
- Encapsulation of ammonia (NH3) into the fullerene cage.
- Characterization using Nuclear Magnetic Resonance (NMR) spectroscopy and MALDI-TOF mass spectrometry.
Main Results:
- Proton NMR confirmed endohedral NH3 presence with a characteristic resonance at delta H = -12.3 ppm.
- MALDI-TOF mass spectrometry verified the intact fullerene and the fullerene-ammonia complex.
- An incorporation fraction of 35-50% was determined, decreasing over six months, indicating ammonia escape.
Conclusions:
- Ammonia can be successfully encapsulated within the studied open-cage fullerene.
- The fullerene-ammonia complex exhibits measurable stability, but slow ammonia diffusion occurs over time.
- This study provides insights into the host-guest chemistry of open-cage fullerenes and guest molecule dynamics.
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