Tetraferrocenylporphyrins as active components of self-assembled monolayers on gold surface

Abstract

Novel tetraferrocenylporphyrins-containing self-assembled monolayers were prepared employing two different approaches. Self-assembled monolayers were characterized using UV-Vis spectroscopy and cyclic voltammetry (CV) whereas their photoelectrochemical properties were investigated by photocurrent generation (PG) experiments.Porphyrin-based self-assembled monolayers (SAMs) were widely investigated in the last two decades, due to their remarkable electrochemical and photophysical properties that resulted in several molecular electronic applications.

Electronic Properties of Mono‐Substituted Tetraferrocenyl Porphyrins in Solution and on a Gold Surface: Assessment of the Influencing Factors for Photoelectrochemical Applications

“…In contrast to the above reported well-resolved four individual single electron oxidation processes, the electrochemical profiles of the modified electrodes resemble those reported in acetonitrile/ TBAP system, [15] consisting of two redox waves (see the DPV in Figure 10) in which a "3 + 1" mechanism of electron transfer can be recognized. Moreover, the first process was found to occur at a lower potential using tetrakis(pentafluorophenyl)borate anion, as suggested by the half-wave potentials in Table 4.…”

“…[15] In particular, a mixed SAM of 1-butanethiol and 5-[1'-(6-thioacetylhexanoyl)ferrocenyl]-10,15,20-triferrocenylporphyrin (Figure 8 A) exhibited an interesting electrochemical behavior in which a "3+ 1" oxidation pattern in acetonitrile/TBAP system was detected. The same film is able to reduce the atmospheric dioxygen dissolved in water under photo-stimulation in the visible region of the spectrum, using Na 2 SO 4 as the supporting electrolyte at 0.0 V applied potential.…”

“…The tetrabutylammonium tetrakis(pentafluorophenyl)borate (TBAF) was used in anhydrous CH 2 Cl 2 for electrochemical studies, after preparation according to previously reported procedures. [15] Computational Aspects…”

“…[36] SAMs were prepared as previously described, [15] that is by soaking the gold electrode in a 0.2 mm solution of the porphyrin in dichloromethane containing 5 equiv of 1-butanethiol for 20 h. The gold foils were then thoroughly rinsed with CH 2 Cl 2 and dried with N 2 . Film formation was monitored by cyclic voltammetry using K 3 [Fe(CN) 6 ] as redox probe.…”

“…[14] Moreover, recently we communicated the first example of ferrocenyl-containing porphyrin, which was linked to SAM by porphyrin-ferrocene-linker-Au covalent bond, [15] whereas all other SAMs were prepared using porphyrin-linker-Au bonding or axial coordination to Au surface. [14] Preliminary photocurrent generation experiments showed that the covalently bound metal-free TFcPs are able to catalytically reduce dioxygen under photostimulation.…”