Double-core nanothread formation from α-furil via a pressure-induced planarization pathway.

Area of Science:

• Materials Science
• Organic Chemistry
• Polymer Chemistry

Background:

• The properties of carbon nanothread materials are significantly influenced by the packing and geometry of their small molecule precursors.
• Competing reaction pathways and molecular phase transitions can negatively impact the structural ordering and chemical homogeneity of nanothread products.

Purpose of the Study:

• To investigate the formation of well-ordered, double-core nanothreads from compressed α-furil.
• To explore a unique polymorphic transition pathway that facilitates pressure-induced reactions for controlled nanothread synthesis.

Main Methods:

• Compression of α-furil to approximately 1.6 GPa to induce a polymorphic transition.
• Analysis of the resulting crystalline packing and molecular conformation (trans-planar).
• Investigation of Diels-Alder cycloaddition reactions and subsequent nucleophilic addition reactions.

Main Results:

• Observed the formation of a photoactive trans-planar conformation of α-furil at ~1.6 GPa, a previously theorized but unobserved state.
• Demonstrated that the crystalline packing of the trans-planar structure promotes topochemical-like Diels-Alder reactions.
• Successfully synthesized double-core nanothreads with chemically homogenous cores through controlled reaction pathways and crosslinking.

Conclusions:

• A novel polymorphic transition pathway in α-furil under pressure enables the formation of highly ordered double-core carbon nanothreads.
• The observed trans-planar conformation and subsequent Diels-Alder reactions are key to achieving controlled synthesis and structural integrity of the nanothreads.