Title

Stimuli-Responsive Cyclopenta ef heptalenes: Synthesis and Optical Properties

Authors

Authors

E. H. G. Zadeh; A. W. Woodward; D. Richardson; M. V. Bondar;K. D. Belfield

Comments

Authors: contact us about adding a copy of your work at STARS@ucf.edu

Abbreviated Journal Title

Eur. J. Org. Chem.

Keywords

Cyclopenta[ef]heptalene; Stimuli response; Azulene; Electron transfer; Photoacid generator; Sensitizers; Photochromism; Natural products; Dyes; pigments; CONJUGATED OLIGOMERS; ENERGY-TRANSFER; AZULENE; CHROMOPHORES; PORPHYRIN; POLYMERS; Chemistry, Organic

Abstract

We report the one-pot synthesis, 1D and 2D NMR characterization, and UV/Vis study of a series of cyclopenta[ef]heptalenes 4a-c that exhibit strong stimuli-responsive behavior, with a tunable energy gap as a result of perturbation of HOMO, LUMO, and LUMO+1 energies upon doping/dedoping with TFA/Et3N. The approach employed allows for the extension of conjugation at C-4 of the cyclopenta[ef]heptalene skeleton from X = H (4a) to X = CN (4b) and X = 2-thiophenyl (4c), resulting in longer absorption maxima and smaller optical energy gaps of the cyclopenta[ef]heptalenium cations 4a-c(+). Additionally, in the presence of a UV-activated (< 300 nm) photoacid generator (PAG), protonation of 4c can be indirectly achieved by intermolecular photoinduced electron transfer (PeT) from the excited state of 4c to the PAG, upon which the latter undergoes photodecomposition resulting in the generation of acid. This phenomenon facilitates the use of cyclopenta[ef]heptalenes 4a-c as visible sensitizers of commercial PAGs.

Journal Title

European Journal of Organic Chemistry

Issue/Number

10

Publication Date

1-1-2015

Document Type

Article

Language

English

First Page

2271

Last Page

2276

WOS Identifier

WOS:000352110600023

ISSN

1434-193X

Share

COinS