Carbon Nanohoops: Molecular Templates for Precision Nanotube Synthesis

APPLICATIONS OF TECHNOLOGY:

Semiconductors
Photonics
Photovoltaics

ADVANTAGES:

Produce smallest building block of an armchair nanotube
Serve as templates for making uniform nanotube structures at high yields
Permit rational design of nanotubes
Method may be used to synthesize other nanotube structures

ABSTRACT: Ramesh Jasti and Carolyn Bertozzi of Berkeley Lab have developed a technique to build carbon-ring “nanohoops,” molecular building blocks for the formation of carbon nanotubes. Carbon nanohoops might serve as seeds, or templates, for the efficient and large-scale synthesis of nanotubes of exceptional precision and uniformity. Nanohoops are cycloparaphenylenes, carbon-ring structures that are the smallest sub-units of “armchair” nanotubes, which have unique electrical and optical properties. The armchair form is characterized by thin walls and a much higher conductivity than copper.

Current nanotube production techniques result in low yields. Bulk scale production has not been feasible, because desired structures must be sorted from batches of randomly varied nanotube architectures and traits. This mixture of atomic arrangements produces carbon nanotubes with vastly different electrical and optical properties, a significant hurdle for their use in advanced nanotechnology applications. The successful production of cycloparaphenylene nanohoops could lead to the preparation of carbon nanotubes with a predefined arrangement of atoms. This rational design process would sidestep the arduous and inefficient separation methods currently used to harvest carbon nanotubes of a desired kind.

Long before carbon nanotubes were conceived of, organic chemists were intrigued by the striking symmetrical structure of cycloparaphenylenes. Since the early 1930’s, attempts to synthesize them have failed due to the tendency of carbon atoms to organize in planar, rather than curved structures. The Berkeley Lab team solved this longstanding structural chemistry challenge by discovering a method to bend carbon components into arcs that subsequently can be assembled into hoops.

DEVELOPMENT STAGE: Bench scale prototype.

STATUS: Patent pending. Available for licensing or collaborative research.

FOR MORE INFORMATION:

Jasti, R., Bhattacharjee, J., Neaton, J.B., Bertozzi, C.R. “Synthesis, Characterization, and Theory of [9]-,[12]-, and [18]Cycloparaphenylene: Carbon Nanohoop Structures,” J. Am. Chem. Soc. 130:17646-17647 (2008)

Jasti, R., Bertozzi, C.R. “Progress and challenges for the bottom-up synthesis of carbon nanotubes with discrete chirality,” Chemical Physics Letters 494:1-7 (2010)

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REFERENCE NUMBER: IB-2753

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