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Donor–Acceptor 1,4‐Fluorenylene Chromophores: Photophysics, Electrochemistry, and Synthesis through a Route for Asymmetric Chromophore Preparation
Author(s) -
Laughlin Brynna J.,
Burdette Mary K.,
Powell Chadwick R.,
Levy Benjamin E.,
Tennyson Andrew G.,
Smith Rhett C.
Publication year - 2014
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.201402181
Subject(s) - chemistry , chromophore , phosphonium , solvatochromism , photochemistry , homo/lumo , fluorene , cyclic voltammetry , tetrahydrofuran , electrochemistry , organic chemistry , molecule , electrode , solvent , polymer
Fourteen chromophores of the form 1‐(4‐X‐styryl)‐4‐(4‐nitrostyryl)benzene or 1‐(4‐X‐styryl)‐4‐(4‐nitrostyryl)fluorene have been synthesized with X = CF 3 , Cl, I, H, CH 3 , OCH 3 , or OCH(CH 3 ) 3 . An innovative synthetic route was developed in the course of this work wherein phosphonium‐phosphonate ester bifunctional precursors were employed. By exploiting steric considerations and the difference in acidity of protons in the position alpha to the phosphonium and phosphonate ester, target asymmetric chromophores were assembled in a straightforward fashion with high selectivity. The photophysical characteristics of the chromophores are described, including notable solvatochromism revealed by measuring photophysical properties in acetonitrile, dichloromethane, tetrahydrofuran, and toluene. Electrochemical analysis by cyclic voltammetry, along with DFT calculations (B3LYP‐6‐31G*) were employed to reveal the HOMO and LUMO distributions and energies, thus providing further understanding of the properties of these materials and the similarities/differences between phenylene‐centered and fluorenylene‐centered chromophores.