Metallization of Organic Surfaces: Pd on Thiazole

Abstract

Results from electrochemical studies, in situ STM, and ex situ angle-resolved XPS on self-assembled monolayers (SAMs) of thiazole on Au(111) are reported for the first time. Although STM seems to indicate a low density of molecules organized in small ordered domains, a quantitative chemical analysis of the sample surface by XPS clearly points toward the formation of a densely packed molecular layer. The stability of the thiazole SAM against reductive desorption is found to be very comparable with that for thiol-SAMs on gold. This results from the formation of Au-S bonds between the molecules and their support as evidenced by XPS, thereby rebuting speculations that the ring nitrogen is responsible for the attachment of such molecules to gold surfaces. Consequently, the N-atoms terminating the molecular layer are available as active sites for the complexation with Pd ions thereby allowing the deposition of Pd islands with monatomic height on top of the thiazole SAM. The importance of such studies for metal-molecule interconnections is briefly addressed.

Metallization of Ultra‐Thin, Non‐Thiol SAMs with Flat‐Lying Molecular Units: Pd on 1, 4‐Dicyanobenzene

“…A similar discrepancy between structure-derived (STM, XPS) and charge-derived coverage has been observed recently for thiazole-SAMs on Au(111). [18] An in situ STM image of a DCB-covered Au(111) electrode after complexation with Pd 2 + and reduction is presented in Figure 7. Like for the metallization of thiol-SAMs, the DCB-SAM is covered with islands of monatomic height, which on the basis of XPS experiments can safely be assigned to Pd metal (oxidation state zero).…”

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

“…[24][25][26][27] Recently a very powerful new approach was introduced by Kolb and co-workers, which may be considered a major step-forward for production of top metallic electrodes on SAMs. [28][29][30][31][32][33][34][35][36] This method is based on SAMs made from organothiols consisting of nitrogen-containing electronegative termination groups (e.g. 4-mercaptopyridine-, 4-aminothiophenol-, 1,4-dicyanobenzene-and thiazole-SAMs).…”

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

“…Originally demonstrated by Pd metallisation of am ercaptopyridine SAM on Au(111), the scheme has been extended to different metals (e.g.,P d, Pt, Au, Rh), different coordinating moieties (-SH, thiazoleo ramino), and SAMs of differentm olecular architectures. [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.…”