On the complexation kinetics for metallization of organic layers: palladium onto a pyridine-terminated araliphatic thiol film

Abstract

Palladium nanoparticles have been deposited electrochemically onto self-assembled monolayers (SAMs) of 4-(4-(4-pyridyl)phenyl)phenylmethanethiol. A pronounced correlation between the kinetics of the complexation between pyridine nitrogens and Pd cations and the sample potential has been observed. The amount of the Pd deposit significantly increases by adjusting the sample potential during the complexation step to values below the point of zero charge. The size of the spherical shaped Pd nanoparticles varies within a certain limit according to the amount of Pd(2+) ions initially coordinated on top of the SAM. The metallic state of these particles was confirmed by X-ray photoelectron spectroscopy and infrared reflection-absorption spectroscopy. Moreover, CO adsorption on the clean Pd deposit revealed further information about the crystallographic orientation of the nanoparticles.

Modulation of electrochemical hydrogen evolution rate by araliphatic thiol monolayers on gold

“…Self-assembled monolayers (SAMs) are often employed for electrochemical applications such as control of charge transfer [1, 2], production of (bio)electrochemical sensors [3–5], metal/organic/metal junctions [6–8], and barrier layers against metal corrosion [9–11]. It is essential to understand the effect of SAM–modified electrodes on electron transfer reactions, as well as their interfacial structure under electrochemical conditions for their ultimate use in electrolytic media.…”

Electrodeposition of gold templated by patterned thiol monolayers

“…The principle has been demonstrated for uniform thiol SAMs featuring tail groups which coordinate metal ions [74][75][76][77][78][79]. Upon reduction of the ions the metal forms 2D or 3D clusters on top of the SAM.…”

“…Furthermore, if the ions are discharged at the outer surface of the SAM which is accomplished by coordinating the ions to the terminal group of the SAM, the neutral metal species do not penetrate but diffuse at the SAM/electrolyte interface to form 2D islands and 3D clusters on top of the SAM [74][75][76][77][78][79].…”

Density Functional Theory Study of Pd Aggregation on a Pyridine‐Terminated Self‐Assembled Monolayer

“…In experiments of Pd depositiono nt op of SAMs, [14,18,25,26] Pd II ions coordinated to nitrogen are electrochemically reduced. Thus, it is reasonablet oa ssume that Pd atoms bondedt oN ( Figure 3a)r epresent the structure immediatelya fter metal discharge.…”

“…[14,[16][17][18][19][20][21][22][23][24][25][26][27][28] Determined by am olecular property insteado f ad efect in the SAM, the coordination mediated deposition scheme not only provides routine access to metal/SAM/metal sandwich structures but also offers new opportunities for metal deposition on SAMsi ncluding bimetallic systems through the combined deposition of coordinated metal and metal from the bulk electrolyte. [25,29] Even though variousm etalsh ave been successfully deposited on top of different SAMs by employing the coordination controlled scheme, the underlying mechanism and the factors controlling metal nucleation and growth at the outer SAM interface remainl argely unclear.T his is highlighted by the morphologyo ft he metal deposits for which both two-dimensional monoatomic-heighti slands [14, 19, 22-24, 27, 28] and three-dimensional particles af ew nanometres in size [18,25,26] have been reported, but the cause of the differences in morphology are not understood. As the timescale on which the initial stages of the deposition occur limits experiments to an ap osteriori characterisation, tackling the problem from the computational side is an essential complementary approach to gain insighti nto the processes involved in the very early stages of the deposition process.…”