Electron Transfer and Electron Excitation Processes in 2,5‐Diaminoterephthalate Derivatives with Broad Scope for Functionalization

Abstract

Derivatives of 2,5‐diaminoterephthalate (DAT) are efficient fluorescence dyes that are also redox‐active, thus allowing for the electrochemical manipulation of spectral properties. The electrochemical behaviour of seven DAT derivatives was studied by cyclic voltammetry in dichloromethane. In the absence of a proton donor, DATs should be oxidized in two one‐electron steps. The first step is usually quasi‐reversible while the second step is either quasi‐reversible or irreversible. Some electrochemical properties such as the formal potentials and the ratio between the anodic and the cathodic current were determined from the cyclic voltammograms. Correlation between the formal potential of first oxidation and the absorption or the fluorescence emission wavelengths are established for this specific type of dyes. These correlations were confirmed with density functional theory calculations.

Structural Flexibility Slows Down Charge Transfers in Diaminoterephthalate-C60 Dyads

“…The DAT-L 1 absorption (blue solid line) shows a characteristic broad absorption band centered around 480 nm without a clear vibronic structure. This corresponds to the HOMO–LUMO transition of the chromophore. , Light absorption into higher-lying electronic states sets in below 300 nm. MPC 60 (black dashed line) displays the characteristic featureless absorption of a C 60 fullerene derivative in the blue spectral range. − The absorption of MPC 60 strongly increases in the UV region.…”

“…This corresponds to the HOMO−LUMO transition of the chromophore. 27,54 Light absorption into higher-lying electronic states sets in below 300 nm. MPC 60 (black dashed line) displays the characteristic featureless absorption of a C 60 fullerene derivative in the blue spectral range.…”

“…The driving force for a light-induced charge separation in the dyads can be analyzed using cyclic voltammetry (CV). 54 Measurements are performed on both the DAT-L 1 donor and the MPC 60 acceptor in the solvent dichloromethane (Figure 2a,b). Experimental details can be found in Methods.…”

Electrochemical Activation of Self-Assembled Monolayers for the Binding of Effectors

“…19 By these substitutions, the emission spectra of the group change in a characteristic way, 19 which was used for the construction of turn-on dyes. 20,21 The combination of up to four substitution positions and the concomitant systematic change of spectroscopic and electrochemical properties 22 have already been utilized for application in life sciences and materials science. 19,23,24 The use of DATs as the terminal group in SAMs, as explored for the first time in this paper, is very attractive because it is expected that the SAM can bind effectors to the surface after electrochemical activation and that this binding event can be monitored by cyclic voltammetry and/or by fluorescence detection.…”