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. 2008 Dec 31;130(52):17646-7.
doi: 10.1021/ja807126u.

Synthesis, characterization, and theory of [9]-, [12]-, and [18]cycloparaphenylene: carbon nanohoop structures

Ramesh Jasti  1 , Joydeep Bhattacharjee, Jeffrey B Neaton, Carolyn R Bertozzi
Affiliations
Free PMC article

Synthesis, characterization, and theory of [9]-, [12]-, and [18]cycloparaphenylene: carbon nanohoop structures

Ramesh Jasti et al. J Am Chem Soc. .
Free PMC article

Abstract

The first synthesis and characterization of [9]-, [12]-, and [18]cycloparaphenylene was demonstrated utilizing a novel aromatization reaction. We refer to these fascinating structures as "carbon nanohoops" due to their structural similarity to carbon nanotubes. Additionally, we have utilized computational methods to understand the unique properties of these fully conjugated macrocycles.

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Figures

Figure 1
Figure 1
Cycloparaphenylenes (1) and a schematic of their radially oriented p orbitals (2).
Scheme 1
Scheme 1. Preparation of Macrocyclic Precursors
Reagents and conditions: (a) (i) nBuLi, THF, −78 °C, (ii) benzoquinone; (b) (i) NaH, THF, 0 °C, (ii) MeI, 0 °C to rt; (c) (i) nBuLi, THF, −78 °C, (ii) isopropyl pinacol borate (Bpin), −78 °C; (d) Pd(PPh3)4, Cs2CO3, toluene/methanol (10:1), 80 °C.
Figure 2
Figure 2
Aromatization reaction and proposed mechanism.
Figure 3
Figure 3
(a) Absorption (solid line) and fluorescence (dashed line) spectra of carbon nanohoops 9, 10, and 11. (b) Energy-minimized geometry of carbon nanohoop 9 by DFT calulations.
See this image and copyright information in PMC

References

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