Electrochemical properties of protoporphyrin IX zinc(II) films

Structure and growth mechanism of self-assembled monolayers of metal protoporphyrins and octacarboxylphthalocyanine on silicon dioxide

“…The same results are reported by Hirano et al 35 Aer cyclic voltammetric measurements, they observed an irreversible oxidation of ZnPP lm leading to a disappearance of absorption bands. This decrease could be approximated by the following exponential decay law for the absorbance: with t 1 ¼ 2.6 days, t 2 ¼ 16.5 days, A ¼ 0.02 and B ¼ 0.01 When ZnPP lm is stored under argon atmosphere (not shown) with a very low oxygen amount (less than 0.1 ppm), this decrease is not observed.…”

“…So in presence of oxygen, the electronic features of ZnPP layer are altered. The same results are reported by Hirano et al 35 Aer cyclic voltammetric measurements, they observed an irreversible oxidation of ZnPP lm leading to a disappearance of absorption bands. This was attributed to formation of dioxoporphomethene.…”

Square wave voltammetry based electrochemical determination of affinity of cholesterol triethylene glycol modified DNA-aptamers for protoporphyrin IX

“…It can be extracted from this experiment that conjugation of cholesterol triethylene glycol to OKA_24 ( = 27.62 ± 1.2 nM) and OKA_26 ( = 15.2 ± 1.68 nM) leads to decrease in binding affinity for heme by 3-fold in both COL-TEG_26-OKA ( = 4 7.13 ± 3.767 nM) and COL-TEG_24-OKA ( = 84.6 ± 8.7 nM) conjugate. Despite the fact that these findings disagreed with the prior findings obtained by carrying out an ultraviolet visible spectrum titrations of native and lipid conjugated aptamers with heme, [5] , it is not surprising because of the role played by the environmental influence on the conformation of molecules which can either enhance or reduce their activity [20] , [21] . Immobilization of heme on a glutaraldehyde-cysteamine coated gold electrode, for example, improved the binding affinity of both modified and unmodified aptamers for heme relative to their respective binding affinity in buffer solutions analyzed by UV spectral titration [5] (data not shown).…”

Supramolecular arrangements of an organometallic forming nanostructured films

“…Most applications involving porphyrins and their derivatives are related to devices such as catalysts [16][17][18] and sensors [19][20][21][22][23][24] . Therefore, it is essential the improvement and the development of techniques to obtain porphyrin forming supramolecular structures 25 . On this sense, several kinds of techniques such as micelles 26 , vesicles 27 , Langmuir-Blodgett (LB) films 28,29 , Langmuir-Schaefer (LS) films 3,4 and Layerby-Layer films 30,31 have been applied and optimized.…”

“…On this sense, several kinds of techniques such as micelles 26 , vesicles 27 , Langmuir-Blodgett (LB) films 28,29 , Langmuir-Schaefer (LS) films 3,4 and Layerby-Layer films 30,31 have been applied and optimized. Among them, LB and LS techniques represent widely employed deposition methods to fabricate porphyrin thin films in a controlled way onto solid substrates 25,32 . The conventional LB and LS techniques allow a supramolecular arrangement that can influence the optical and electrical properties of a deposited film and, as a consequence, the variation of such parameters can be targeted according to desired application to the high-performance devices 32 .…”