Preparation of Covalent Long-Chain Trialkylstannyl and Trialkylsilyl Salts and an Examination of their Adsorption on Gold

Abstract

We report the attachment of alkyl residues to a gold surface through a tin atom. Covalent trialkylstannyl and trialkylsilyl salts of trifluoromethanesulfonic, trifluoroacetic, and p-toluenesulfonic acids containing one to three C(18)H(37) chains and two to no CH(3) groups in the molecule have been synthesized. They were tested for adsorption on gold from solution under ambient conditions using ellipsometry, FTIR spectroscopy, contact angle, and electrode-blocking measurements. All nine trialkylstannyl salts form similar stable monolayers with the loss of the acid residue and form no multilayers. The monolayers differ from those formed from alkanethiols. They are much thinner, less ordered, less hydrophobic, and only slightly electrode-blocking. Their stability to solvents, bases, acids, and reductants is somewhat lower than that of a 1-octadecanethiol monolayer, but their resistance to heat and oxidants, including air, is slightly better. The distinctive properties of these monolayers may be of interest in certain circumstances, but we expect the attachment of molecules to gold through a tin atom to be of the most value in work with single-molecule structures. The trialkylsilyl salts showed no tendency to adsorb onto gold under these conditions.

Stable Carboxylate‐Terminated Gold Surfaces Produced by Spontaneous Grafting of an Alkyltin Compound

“…In our case, the presence of Sn (Figure 3d and Figure SI-4c in the Supporting Information;X PS signals of Sn 3d 5/2 at 487.3 eV and Sn 3d 3/2 at 496.2 eV)s uggested the formationo f coordination compounds with the oxygen atoms of the free carboxylic moieties by releasing the chlorine groups, which produced negligible XPS signals (Figure 3e and FigureSI-4 di n the SupportingI nformation). This promotes the formation of thicker layers (Figure 4) than those reported for neutral compounds, [22][23][24] and that reported for am onolayer of mercaptopropionic acid. [28] An estimation of the thickness of the organic layer was carried out by calculating the average layer thickness based on the attenuation of the XPS Au 4f 7/2 peak following surface modification.…”

“…XPS analyses also supported the successfulo rganic graftingo nto the gold substrates because the [22] for neutrala lkyltin derivatives deposited on gold. XPS analyses also supported the successfulo rganic graftingo nto the gold substrates because the [22] for neutrala lkyltin derivatives deposited on gold.…”

“…The same substrates characterisedb yP M-IRRAS were then studied by meanso fX PS. XPS analyses also supported the successfulo rganic graftingo nto the gold substrates because the [22] for neutrala lkyltin derivatives deposited on gold.…”

Reversible on-surface wiring of resistive circuits

“…Alkanethiol monolayers have been reported to desorb upon exposure to strong acids/bases, oxidizing/reducing conditions, particular solvents or temperatures above ∼100 °C. 52–54 Their stability is also a function of intermolecular interactions such as van der Waals forces 55 or hydrogen bonding, 56,57 not just the Au–S bonding motif. After testing different reaction conditions ( e.g.…”

Precise Control of Interfacial Charge Transport for Building Functional Optoelectronic Devices

“…We list below three general methods for in situ generation of AuC covalent contacts. The first method adopts the reactivity of CSnR 3 bonds based on transmetalation to generate AuC bonds on gold surfaces . However, this approach uses and produces toxic and volatile trimethyltin species, which limits its wide application.…”