Chemistry through cocrystals: Pressure-induced polymerization of C2H2·C6H6 to an extended crystalline hydrocarbon

Matthew D. Ward, Haw Tyng Huang, Li Zhu, Arani Biswas, Dmitry Popov, John V. Badding, Timothy A. Strobel

Research output: Contribution to journalArticlepeer-review

9 Scopus citations


The 1:1 acetylene-benzene cocrystal, C2H2·C6H6, was synthesized under pressure in a diamond anvil cell (DAC) and its evolution under pressure was studied with single-crystal X-ray diffraction and Raman spectroscopy. C2H2·C6H6 is stable up to 30 GPa, nearly 10× the observed polymerization pressure for molecular acetylene to polyacetylene. Upon mild heating at 30 GPa, the cocrystal was observed to undergo an irreversible transition to a mixture of amorphous hydrocarbon and a crystalline phase with similar diffraction to i-carbon, a nanodiamond polymorph currently lacking a definitive structure. Characterization of this i-carbon-like phase suggests that it remains hydrogenated and may help explain previous observations of nanodiamond polymorphs. Potential reaction pathways in C2H2·C6H6 are discussed and compared with other theoretical extended hydrocarbons that may be obtained through crystal engineering. The cocrystallization of benzene with other more inert gases may provide a novel pathway to selectively control the rich chemistry of these materials.

Original languageEnglish (US)
Pages (from-to)7282-7294
Number of pages13
JournalPhysical Chemistry Chemical Physics
Issue number10
StatePublished - 2018

All Science Journal Classification (ASJC) codes

  • Physics and Astronomy(all)
  • Physical and Theoretical Chemistry

Fingerprint Dive into the research topics of 'Chemistry through cocrystals: Pressure-induced polymerization of C<sub>2</sub>H<sub>2</sub>·C<sub>6</sub>H<sub>6</sub> to an extended crystalline hydrocarbon'. Together they form a unique fingerprint.

Cite this