Synthesis of Linear Acetylenic Carbon: The " sp " Carbon Allotrope

Abstract

A carbon allotrope based on "sp" hybridization containing alternating triple and single bonds (an acetylenic or linear carbon allotrope) has been prepared. Studies of small (8 to 28 carbon atoms) acetylenic carbon model compounds show that such species are quite stable (130 degrees to 140 degrees C) provided that nonreactive terminal groups or end caps (such as tert-butyl or trifluoromethyl) are present to stabilize these molecules against further reactions. In the presence of end capping groups, laser-based synthetic techniques similar to those normally used to generate fullerenes, produce thermally stable acetylenic carbon species capped with trifluoromethyl or nitrile groups with chain lengths in excess of 300 carbon atoms. Under these conditions, only a negligible quantity of fullerenes is produced. Acetylenic carbon compounds are not particularly moisture or oxygen sensitive but are moderately light sensitive.

Homo-coupling of terminal alkynes on a noble metal surface

“…It is suggested that terminal alkyne building blocks can be in general covalently linked on suitable noble metal surfaces to create novel molecular compounds, low-dimensional superstructures or coherently reticulated polymeric layers. This provides a new synthesis route towards conjugated molecular nanosystems and networks, providing potential for the fabrication of regular 1D scaffolds, such as carbyne 40,41 , 2D polymers, such as graphyne or graphdiyne 6,42 , and similar hydrocarbon membranes. We furthermore envision the use of nanostructured interfaces and noble metal nanoparticles as catalytic materials and reaction templates under vacuum or other conditions.…”

Communication: Stable carbon nanoarches in the initial stages of epitaxial growth of graphene on Cu(111)

“…[17][18][19] However, little has been experimentally demonstrated mainly due to the lack of a reliable and effective fabrication method. [20][21][22][23][24] The present work suggests that such 1D carbon chains can be formed via self-assembly on Cu(111) substrates.…”

Quasiparticle and excitonic gaps of one-dimensional carbon chains

“…We have therefore studied the effect of multideterminant (MD) Slater-Jastrow trial wave functions for excited, cationic, and anionic states of oligoynes with 4,6,8,10, and 24 carbon atoms as well as a supercell of polyyne composed of 8 primitive cells. The Slater determinants in the MD wave functions contained all the orbital occupancies that are degenerate at the single-particle level.…”

“…The observed presence of carbon chains in interstellar space and circumstellar shells 1,2 has inspired considerable effort to synthesise polyyne in the laboratory, leading among other things to the discovery of fullerenes 3 . Recent experiments have shown that it is possible to produce a long linear chain of more than 200 carbon atoms inside a protector such as a double-walled carbon nanotube (DWCNT) 4 and also to synthesise stable oligoynes (short polyyne molecules) with up to 44 carbon atoms 5 and a variety of terminal groups [6][7][8][9][10][11][12] . Polyyne is of particular interest as the ideal interconnect in single-molecule nanoelectronic circuitry, including spintronic devices [13][14][15][16] , and has potential applications in nanomechanical devices [17][18][19] .…”