TY - JOUR
T1 - Nanoribbons or weakly connected acenes? The influence of pyrene insertion on linearly extended ring systems
AU - Ai, Qianxiang
AU - Smith, Tanner
AU - Liyanage, A. D.Thilanga
AU - Mazza, Samuel M.
AU - Parkin, Sean R.
AU - Anthony, John E.
AU - Risko, Chad
N1 - Publisher Copyright:
© The Royal Society of Chemistry.
PY - 2021/12/21
Y1 - 2021/12/21
N2 - 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.
AB - 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.
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U2 - 10.1039/d1tc05193h
DO - 10.1039/d1tc05193h
M3 - Article
AN - SCOPUS:85121274569
SN - 2050-7534
VL - 9
SP - 16929
EP - 16934
JO - Journal of Materials Chemistry C
JF - Journal of Materials Chemistry C
IS - 47
ER -