From Linear Molecular Chains to Extended Polycyclic Networks: Polymerization of Dicyanoacetylene
Journal
Chemistry of Materials
Journal Volume
29
Journal Issue
16
Start Page
6706
End Page
6718
ISSN
08974756
Date Issued
2017
Author(s)
Gou, Huiyang
Zhu, Li
Biswas, Arani
Keefer, Derek W.
Chaloux, Brian L.
Prescher, Clemens
Yang, Liuxiang
Kim, Duck Young
Ward, Matthew D.
Lerach, Jordan
Wang, Shengnan
Oganov, Artem R.
Epshteyn, Albert
Badding, John V.
Strobel, Timothy A.
Abstract
Dicyanoacetylene (C4N2) is an unusual energetic molecule with alternating triple and single bonds (think miniature, nitrogen-capped carbyne), which represents an interesting starting point for the transformation into extended carbon-nitrogen solids. While pressure-induced polymerization has been documented for a wide variety of related molecular solids, precise mechanistic details of reaction pathways are often poorly understood and the characterization of recovered products is typically incomplete. Here, we study the high-pressure behavior of C4N2 and demonstrate polymerization into a disordered carbon-nitrogen network that is recoverable to ambient conditions. The reaction proceeds via activation of linear molecules into buckled molecular chains, which spontaneously assemble into a polycyclic network that lacks long-range order. The recovered product was characterized using a variety of optical spectroscopies, X-ray methods, and theoretical simulations and is described as a predominately sp2 network comprising "pyrrolic" and "pyridinic" rings with an overall tendency toward a two-dimensional structure. This understanding offers valuable mechanistic insights into design guidelines for next-generation carbon nitride materials with unique structures and compositions. © 2017 American Chemical Society.
Publisher
American Chemical Society
Type
journal article