Electrochemical and Spectroscopic Properties of Indolizino[1,2-B] Quinole Derivates

Abstract

A series of indolizino [1,2-b] quinole derivates compounds were characterized by various electrochemical and spectroscopic techniques. Electrochemical studies reveal that there are two redox processes controlled by diffusion, the first step corresponds to the formation of a semiquinone radical Q•− , while the second step corresponds to the formation of quinone dianion, Q 2− . The presence of acceptor groups such as -CN and -COOH shifted reduction potentials, due to a more favorable electronic stabilization. There was no significant effect of the substituents on the absorption spectra of indolizino[1,2-b] quinole derivates. The substituents influenced the fluorescence properties from indolizino[1,2-b] quinole derivates. The emission and excitation spectra obtained of these compounds suggested that the molecule emits from a locally excited state having identical geometry with that of ground state geometry. Finally it was observed that the group with higher acceptor capacity (-CN), has the highest quantum yield, which is indicating that this group always stabilized electronic state with a higher conjugation.

Mapping the DNA Damaging Effects of Polypyridyl Copper Complexes with DNA Electrochemical Biosensors

“…In measurements performed on [Cu(TPMA)(PD)] 2+ , it was determined that the C 1 /A 1 redox coupled is ascribed to the 'Cu(PD) character' of the complex and C 3 /A 3 can be associated with the reversible oxidation of the 1,10-phen-5,6-dione (PD) ligand. Transition metal PD complexes can undergo a two-step 2 electron reduction [46][47][48], while the reduction of the free PD ligand in aqueous solution, from quinone to semiquinone and further to hydroquinone, has also been reported [49,50] (S-3, Figure S7, SM). Moreover, the C 2 peak, also common to the other complexes at −0.4 V, is linked to the A 2 oxidation processes and describes the electroactivity of the reorganised complex ('Cu(TPMA) character').…”

“…S1 and S2: Electrochemical parameters for the copper complexes obtained at the DNA biosensors; Figure S11: Washing of the DNA layer after interaction with [Cu(TPMA)(PD)] 2+ ; Figures S12-S15: The relationship between the oxidation and reduction wave peak currents versus the scan rate, and the square root of the scan rate, at the DNA biosensor; Figures S16-S19: The stability of the complexes at the DNA biosensor; Tables S3-S6: DNA nuclease efficacy of copper complexes. References [17,37,[45][46][47][48][49][50]52,61,64,65] have been cited in the Supplementary Materials.…”