TY - JOUR

T1 - Evidence for the cumulene cyclo[n]carbon formation in a compression reactor during the pyrolysis of acetylene in neon atmosphere

AU - Vasiljev, Sergei

AU - Ezdin, Boris

AU - Shabiev, Farid

AU - Pakharukov, Yuri

AU - Kalyada, Valery

AU - Mavrinsky, Viktor

AU - Shklyaev, Aleksandr

AU - Yanshole, Vadim

AU - Ishchenko, Arkadiy

N1 - All studies were funded by the Russian Science Foundation (Grant # 19–72–30023), except for TEM investigations, which were supported by the Ministry of Science and Higher Education of the Russian Federation (projects FWUR-2024–0032).  The authors declare the following financial interests/personal relationships which may be considered as potential competing interests.

PY - 2025/1/10

Y1 - 2025/1/10

N2 - The article is dedicated to the experimental study of ultra-small carbon particles, containing from several to several tens of carbon atoms. In the absence of sufficient experimental data in this area, the theoretical notion considers carbon polyene structures as of flat rings with alternating triple and single bonds between carbon atoms and an even number of carbon atoms in ring structures as being the more favorable energy-wise. However, currently reliable evidence of the true structure of carbon rings that can occur naturally is lacking. Here, we show that the carbon nanoparticle synthesis by pyrolysis of gaseous hydrocarbons in a cyclic piston-cylinder compression reactor produces carbon rings with double bonds between carbon atoms, i.e. with a cumulene structure, contrary to the current theoretical notion. We believe that the cumulene structures are more favorable energy-wise due to the specific shape of carbon rings, which appear as a Grover washer or a helix turn. Our results are corroborated by MALDI-TOF mass spectrometry, IR spectroscopy, and high-resolution transmission electron microscopy of the samples obtained, as well as by density functional theory calculations. We believe that our work will bring more clarity to the issues surrounding the formation of carbon particles of the smallest sizes.

AB - The article is dedicated to the experimental study of ultra-small carbon particles, containing from several to several tens of carbon atoms. In the absence of sufficient experimental data in this area, the theoretical notion considers carbon polyene structures as of flat rings with alternating triple and single bonds between carbon atoms and an even number of carbon atoms in ring structures as being the more favorable energy-wise. However, currently reliable evidence of the true structure of carbon rings that can occur naturally is lacking. Here, we show that the carbon nanoparticle synthesis by pyrolysis of gaseous hydrocarbons in a cyclic piston-cylinder compression reactor produces carbon rings with double bonds between carbon atoms, i.e. with a cumulene structure, contrary to the current theoretical notion. We believe that the cumulene structures are more favorable energy-wise due to the specific shape of carbon rings, which appear as a Grover washer or a helix turn. Our results are corroborated by MALDI-TOF mass spectrometry, IR spectroscopy, and high-resolution transmission electron microscopy of the samples obtained, as well as by density functional theory calculations. We believe that our work will bring more clarity to the issues surrounding the formation of carbon particles of the smallest sizes.

KW - Carbon nanoparticles

KW - carbyne

KW - cyclo[n]carbon

KW - fullerenes

KW - hydrocarbon pyrolysis

KW - ring carbon structures

UR - https://www.mendeley.com/catalogue/5ca26017-6669-3643-9103-a4868e9e24a5/

UR - https://www.scopus.com/record/display.uri?eid=2-s2.0-85214456952&origin=inward&txGid=43ab760cc974f2dfdc9346c03e1ebd33

U2 - 10.1080/1536383X.2024.2447350

DO - 10.1080/1536383X.2024.2447350

M3 - Article

JO - Fullerenes Nanotubes and Carbon Nanostructures

JF - Fullerenes Nanotubes and Carbon Nanostructures

SN - 1536-383X

ER -