Derived from the lateral fusion of benzene rings, acenes are a class of π-conjugated molecules containing a single aromatic sextet, where system size is inversely correlated with chemical stability. In the pursuit of creating graphene nanoribbons/nanowires, several extended-ring structures have been synthesized through linear combinations of azaacenes and pyrene. Importantly, these extended systems demonstrate enhanced chemical stability and allow for the construction of macromolecular-sized structures. Here, we present a combined quantum-chemical and experimental study to reveal the cost of these improved characteristics in fully carbon-based systems. The results clearly show that pyrene moieties inserted among acene units do not result in long acene-like structures, rather the pyrene-inserted acene is, electronically, a series of (nearly) isolated acenes. The origin of pyrene's electronic blocking effect and implications on oxidized and photoexcited states of these extended-ring systems are detailed. The results of this investigation definitively show that coupling pyrene in an orthogonal orientation (through the 4, 5/9, 10 positions or e/l faces) to acenes should be eschewed if nanographene-/nanowire-like structures are desired.
|Number of pages||6|
|Journal||Journal of Materials Chemistry C|
|State||Published - Dec 21 2021|
Bibliographical noteFunding Information:
This work was supported by the Office of Naval Research (Award No. N00014-18-1-2448 and N00014-16-2390). Portions of this effort were supported by the US. Department of Energy, Office of Basic Energy Sciences (ERW7404). Supercomputing resources were provided by the University of Kentucky Information Technology Department and Center for Computational Sciences (CCS).
© The Royal Society of Chemistry.
ASJC Scopus subject areas
- Chemistry (all)
- Materials Chemistry