Synthesis and Properties of a Novel Electrochromic Polymer Obtained from the Electropolymerization of a 9,9'-Spirobifluorene-Bridged Donor−Acceptor (D−A) Bichromophore System

Abstract

The synthesis and photophysical, electrochemical, and spectroelectrochemical characterization of a novel donor-acceptor (D-A) bichromophore system composed of two D-A segments linking through a spiro center are reported. The electron-donating (D) moieties are triphenylamine (TPA) groups, whereas the electron-withdrawing (A) moieties are cyano groups. The particular "spiro" configuration that perpendicularly bonds the D-A chromophores by a tetrahedral carbon, impedes orbital interactions between the branches. Thus, the two TPA substituents act independently, rendering an efficient electropolymerization process feasible. The polymer film obtained showed reversible electrochemical oxidation accompanied by strong color changes with high coloration efficiency and contrast ratio, which can be switched by potential modulation. The remarkable electrochromic behavior of the film is clearly interpreted on the basis of spectroelectrochemical studies. A plausible polymerization mechanism involved with the TPA dimerization reaction is proposed for the electropolymerization process.

Dispirofluorene–Indenofluorene Derivatives as New Building Blocks for Blue Organic Electroluminescent Devices and Electroactive Polymers

“…As the current keeps more than 95 % of its initial value (after 1000 cycles), these polymers possess highly interesting electrochromic properties. [100] In terms of mechanism, and keeping in mind the electro-A C H T U N G T R E N N U N G polymerisation process of F and 9,9'-SBF already described in literature, [99] we expected that the polymerisation of DSF-IF begins by the one-electron oxidation of the indenofluorenyl part of the molecule at E 1 , followed by the oxidation of the spiro-linked fluorenyl units at E 2 . The cation radical of these units are quickly involved in dimerisation processes.…”

A Joint Experimental and Theoretical Investigation on Nonlinear Optical (NLO) Properties of a New Class of Push–Pull Spirobifluorene Compounds

“…Although several spirobifluorene compounds bearing donor and acceptor residues have been synthesized and employed for example as dyes [19][20][21] or as ambipolar transporting molecules, [22,23] to the best of our knowledge, no experimental data on their hyperpolarizability β have yet been reported. The first hyperpolarizability of spiro-linked push-pull polyenes, where several 1,4-cyclohexadiene rings are connected by the tetrahedral sp 3 carbon atoms and electron-donating and electron-withdrawing groups are introduced in the terminal 1,4-cyclohexadiene rings, has been investigated by using ab initio and INDO/S molecular orbital calculations.…”

Synthesis of electro-optically active polymer composite of poly[2,2'-bis(3,4-ethylenedioxythiophene)-alt-fluorene]/hydroxypropyl cellulose showing liquid crystal structure

“…Electrochemical polymerization is a widely used technique to produce electrochromic materials [1][2][3][4]. Electric field is applied between an anode and a cathode in an electrolyte containing a monomer for performing electrochemical polymerization.…”