XPS, Static SIMS and NEXAFS Spectroscopic Investigation of Thiol Adsorption on Metals and Metal Sulfides

Abstract

Examples are presented of the complementary nature of conventional XPS, synchrotron XPS, ToF-SIMS and NEXAFS spectroscopy when applied to the adsorption of MBT on metals and metal sulfides. Conventional XPS could detect chemisorption via S 2p spectra, detect the onset of multilayer formation via the relevant metal Auger or core level photoelectron spectra, and determine metal thiolate stoichiometry from thick multilayers. Surfaceoptimised synchrotron XPS allowed precise chemisorbed MBT S 2p binding energies to be obtained. Angle-dependent N and C NEXAFS spectra revealed adsorbate orientation, even for an abraded but relatively smooth surface. Cu L 3 -edge spectra detected some Cu(II) and hence Cu(MBT) 2 in multilayers on chalcocite. Static SIMS data confirmed the interaction of both N and exocyclic S with surface metal atoms for silver metal and chalcocite.

4,5‐Bis(diphenylthiophosphinoyl)‐1,2,3‐triazolate interaction with gold nanoparticles and flat surfaces to form self‐assembled monolayers

“…These signals are also comparable with those reported for the 3‐amino‐5‐mercapto‐1,2,4‐triazole adsorbed through the triazolering nitrogen (401.3, 400.2, 398.9, and 162.3 eV) 61 . Other example of a monolayer formed from related adsorbate containing S and N as donor atoms present also similarities with what we found in profile 17,62 . Mercaptobenzothiazolate (MBT) adsorbed on gold exhibits S 2p and N 1s spectra with both SAu and NAu binding (chemisorbed S at 162–162.2 eV and interacting N at 398.7 eV) indicating two diverse MBT adsorption geometries, one with monodentate exocyclic sulfur and other with bidentate MBT molecule interacting with S,N‐chelating mode 17 .…”

Direct Assembly of Hydrophobic Nanoparticles to Multifunctional Structures

“…The strong coordinating interactions between alkanethiols and metal surfaces have been extensively studied and utilized in the formation of self-assembled monolayers (SAMs) on metal surfaces . It has also been reported that alkanethiols can adsorb onto metal oxide surfaces (such as TiO 2 , ZnO, , and SnO 2 ) and semiconductor substrates (such as InP, , InAs, , and GaAs, , and metal sulfides). Recently, the thiol-metal interaction has been used to immobilize nanoparticles on alkanethiol-modified solid substrates − and has been further extended to the colloidal substrates by assembling Au nanoparticles to thiol-functionalized silica colloids. , Philipse et al have explored the attachment of magnetic particles to colloidal silica that was grafted with (3-mercaptopropyl)trimethoxysilane (MPS). , Their efforts, however, have been still limited to only water-soluble γ-Fe 2 O 3 and CoFe 2 O 4 nanoparticles, probably due to the low density of thiol groups achievable during the surface modification of colloidal silica.…”

“…) and semiconductor substrates (such as InP, 36,37 InAs, 38,39 and GaAs, 40,41 and metal sulfides 42 ). Recently, the thiol-metal interaction has been used to immobilize nanoparticles on alkanethiolmodified solid substrates 43À46 and has been further extended to the colloidal substrates by assembling Au nanoparticles to thiol-functionalized silica colloids.…”