Electrochemistry and Electrogenerated Chemiluminescence of BODIPY Dyes

Abstract

BODIPY (boron dipyrromethene) dyes are unique materials with spectroscopic and electrochemical properties comparable to those of aromatic hydrocarbons. Electrochemical studies are useful in understanding the redox properties of these materials and finding structure-stability relations for the radical ions; along with spectroscopy, these studies help researchers design novel compounds with desired properties. This Account represents our attempt at a full description of the electrochemical and electrogenerated chemiluminescence (ECL) properties of the BODIPY dyes. When the dyes are completely substituted with alkyl or other groups, the radical ions of BODIPY dyes are highly stable. But if they include unsubstituted positions, the radical ions can undergo dimerization or other reactions. BODIPY dyes also show unusually large separations, ~1.0 V, between the first and second cyclic voltammetric (CV) waves for both oxidation and reduction half-reactions. Alkyl-substituted BODIPY dyes show good photoluminescence (PL) quantum efficiencies, and radical ion electron transfer annihilation in these molecules produces electrogenerated chemiluminescence (ECL), the intensity of which depends on the structure of the dye. The large separation between waves and the presence of strong ECL signals are both important in the design of stable ECL-based materials. The ECL spectra provide a fast method of monitoring the electrochemical formation of dimers and aggregates from the monomers. BODIPY dyes are particularly good systems for studying stepwise electron transfer in their chemically synthesized oligomers and polymers because of the small separation between the first oxidation and first reduction waves, generally about 2.0-2.4 V, and their relative ease of reduction compared with many other aromatic compounds. The larger separation between consecutive waves for oxidation compared with reduction is noticeable for all BODIPY dimers and trimers. We also observe a more difficult addition or extraction of a third electron compared with the second for the trimers, signaling the importance of electrostatic interactions. In general, BODIPY dyes combine interesting electrochemical and spectroscopic properties that suggest useful analytical applications.

Computational Molecular Electronic Spectroscopy with TD-DFT

“…BODIPY and other similar derivatives relying on a fluoroborate group to ensure the chemical stability of the dyes constitute one of the most important classes of organic emitters [116][117][118]. Indeed, they present sharp fluorescence emission bands and large quantum yields.…”

Theoretical Investigation of Linker Effects on New Designed Bodipy-Ferrocene Based Three Channels Calcium (II) Ion Sensors; as Redox, Colorimetric and Fluorescent Properties

“…Binding a cation to the receiver unit causes a positive shift of the redox potential (Fc/Fc+) and the cause is electrostatic interactions The cation coordination to an Fc host sensor, is expected to result in an anodic shift of the redox potential, making the Fc group more difficult to oxidize [17]. Bigger anodic shift in redox potential means, higher charge density carrying potential, by guest or molecule, or by other words it can shift electron density toward itself [18]. According to electrochemical potential, complexation ability of the bridges can be controlled.…”

Difluoroboranyl derivatives as efficient panchromatic photoinitiators in radical polymerization reactions

“…Among various compounds carrying the BF 2 moiety the most common are boron-dipyrromethenes (BODIPYs) [8,11]. The core of the dyes is a complex of dipyrromethane with a disubstituted boron atom, typically a BF 2 unit [12].…”