Ortho-Branched Ladder-Type Oligophenylenes with Two-Dimensionally pi-Conjugated Electronic Properties
Resource
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 133(20), 8028-8039
Journal
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
Journal Volume
133
Journal Issue
20
Pages
8028-8039
Date Issued
2011
Date
2011
Author(s)
Abstract
The synthesis, photochemical and electrochemical properties, and electronic structures of a series of star-shaped ladder-type oligophenylenes Sn (n = 7, 10, 13, 16, 19, and 22), including one multibranched case S19mb, are reported and compared with the linear para-phenylene ladders Rn (n = 2-5 and 8) and the stepladder analogues SFn (n = 10, 16, and 22). The n value refers to the number of π-conjugated phenylene rings. Functionalized isotruxenes are the key synthetic building blocks, and S22 is the largest monodispersed ladder-type oligophenylene known to date. The Sn systems possess the structural rigidity of Rn and the ortho-para phenylene connectivity of SFn. Consequently, Sn represents the first class of branched chromophores with fully two-dimensional conjugation in both ground- and excited-state configurations. Evidences include the excellent linear correlations for the optical 0-0 energies or the first oxidation potentials of Sn and Rn against the reciprocal of their n values, delocalized HOMO and LUMO based on density functional theory calculations, and molecule-like fluorescence anisotropy. The resulting model of effective conjugation plane (ECP) for the two-dimensional π-conjugated systems compliments the concept of effective conjugation length (ECL) for one-dimensional oligomeric systems. Other implications of the observed structure-property relationships are also included.
Type
journal article
File(s)![Thumbnail Image]()
Loading...
Name
128.pdf
Size
23.15 KB
Format
Adobe PDF
Checksum
(MD5):d68293a6e23c0d66659eaa9716d91468