A Circle Has No End: Role of Cyclic Topology and Accompanying Structural Reorganization on the Hole Distribution in Cyclic and Linear Poly‑p‑phenylene Molecular Wires

Authors

Marat R. Talipov, Marquette UniversityFollow
Ramesh Jasti, University of Oregon
Rajendra Rathore, Marquette University

Document Type

Article

Language

eng

Format of Original

8 p.

Publication Date

12-2015

Publisher

American Chemical Society

Source Publication

Journal of the American Chemical Society

Source ISSN

1520-5126

Original Item ID

DOI: 10.1021/jacs.5b09596

Abstract

π-Conjugated organic oligomers/polymers hold great promise as long-range charge-transfer materials for modern photovoltaic applications. However, a set of criteria for the rational design of functional materials is not yet available, in part because of a lack of understanding of charge distribution in extended π-conjugated systems of different topologies, and concomitant effects on redox and optical properties. Herein we demonstrate the role of cyclic versus linear topology in controlling the redox/optical properties and hole distribution in poly-p-phenylenes (PPs) with the aid of experiment, computation, and our recently developed multistate parabolic model (MPM). It is unequivocally shown that the hole distribution in both cyclic and linear poly-p-phenylene (n ≥ 7) cation radicals is limited to seven p-phenylene units, despite the very different topologies. However, the effect of topology is evidenced in the very different trends in oxidation potentials of cyclic versus linear PPs, which are shown to originate largely from the geometrical distortion of individual p-phenylene units in cyclic PPs. The presence of additional pairwise electronic coupling element in cyclic PPs, absent in linear PPs, plays a significant role only in smaller cyclic PP₅ and PP₆. This study provides a detailed conceptual description of cyclic and linear poly-p-phenylene cation radicals and demonstrates the versatility and predictive power of MPM, an important new tool for the design and synthesis of novel and efficient charge-transfer materials for molecular electronics and photovoltaic applications, an area of widespread interest.

Comments

Accepted version. Journal of the American Chemical Society, Vol. 137, No. 47 (December 2015): 14999–15006. DOI. © 2015 American Chemical Society. Used with permission.

Recommended Citation

Talipov, Marat R.; Jasti, Ramesh; and Rathore, Rajendra, "A Circle Has No End: Role of Cyclic Topology and Accompanying Structural Reorganization on the Hole Distribution in Cyclic and Linear Poly‑p‑phenylene Molecular Wires" (2015). Chemistry Faculty Research and Publications. 456.
https://epublications.marquette.edu/chem_fac/456