Photoinduced Charge Transfer Kinetics and Electrochemical Investigation on Porphyrin
Authors: Lu Xiaoquan , Devaramani Samrat , Zhang Shouting , Li Wenqi , Du Jiajian , Zhang Zhuoyue , Zhang Dongxu 
Published: February 2020

Porphyrin is one of the most attractive molecules for its well known functions in biological and biomimetic systems because of their excellent stability, unique optical and electronic properties.Their electrochemical and photophysical properties make porphyrin derivatives combine with a complementary electron-accepting species to mimic the electron transport of biological process based on the formation of electron donor/acceptor(D/A) system.So Porphyrin compounds are widely employed as platform to recognize various species.

Photoinduced charge transfer (PCT) plays a central role in biologically significant systems and in applications that harvest solar energy. The electron-rich macrocyclic compounds such as porphyrins have been widely used as biomimetic photosensitizing electron donor in these studies, since they absorb lights over wide wavelengths in the visible region and exhibit favorable redox potentials. Our group mainly focus on the PCT kinetics, electron transfer mechanisms of porphyrin and its derivarives. Scanning electrochemical microscopy (SECM), Electrochemical Impedance spectroscopy are the techniques that have been used extensively in our investigatios.

Self-assembled monolayers (SAMs) of thiol-porphyrins with different alkyl chain length (H2TPPO(CH2)nSH, n=3, 6, 9 and 12)，thiol-derivatized tetraphenylporphyrin (SH-TPP) and cobalt tetraphenylporphyrin (SH-CoTPP) on gold electrode have been prepared and their structure, direct electron transfer (ET) process， electrochemical behaviors of a series of SH-Terminated-Functionalized Porphyrinswas studied by electrochemical impedance spectroscopy and SECM. SAMs of thiol-derivatized tetraphenylporphyrin on Gold electrodes was designed to detect H2PO4
-even in the presence of a 10-fold excess of other anions. Substituent effects of iron porphyrin complexes on the structures and kinetic processes have been studied.

We developed a novel SECM model which provide a two-dimensional quantitative analysis on a heterogeneous electron transport (ET) process of a functionalized porpyrin by photoinduced ET at the ITO/liquid interface.

Our liquid-liquid interface works include but not restricted to the following examples. Investigation of Ion Transport Traversing the “Ion Channels”, Consecutive electron transfer of metalloporphyrin species containing different substituents at the Liquid/Liquid Interface by thin-layer cyclic voltammetry, electrochemical properties of metalloporphyrin species at the Liquid/Liquid interface by switching substitutes on the porphyrin ring, current oscillatory phenomena based on Fe3+/Fe2+at the liquid/liquid interface.

Potential electrochemical sensors have been developed for the anaytes which are of environmenal and biological significance. Few examples are, an electrochemical method for the detection of DNA damage by combining the layer-by-layer assembly film with adriamycin (ADM) as an electrochemical probe, recognition of -1,3-glucanase gene (Glu) specific sequence based on probe extension, electrochemical behavior of hydroquinone (HQ) was studied by cyclic voltammetry at a glassy carbon electrode (GCE) modified by a gel containing multi-walled carbon nanotubes (MWNTs) and room temperature ionic liquid (RTIL) of 1-butyl-3-methylimidazolium hexafluorophosphate (BMIMPF6), investigation of the mechanism of the N-H migration in asymmetrical metal-free porphyrins, four porphyrins of electron-withdrawing or electron-donating substituent at the -position were studied theoretically visual colorimetric and electrochemical biosensor for porphyrin, Ag nanoparticles on functionalized graphene for an excellent electrochemical sensor of nitroaromatic compounds methyl-parathion pesticide, based on the advantages of porphyrin and porphyrin derivatives, we envisioned the introduction of the hydroxyphenyl-porphyrin into CNTs could enhance the sensitivity of the detection of explosives basedon the synergetic effects of porphyrin and  CNTs.