1,10-Decanedithiol: Properties, SAM Formation & Lab Uses

1,10-Decanedithiol is a symmetric, bifunctional alkanedithiol featuring a ten-carbon methylene chain terminated at both ends by free thiol (–SH) groups, making it a versatile molecular linker for self-assembled monolayer (SAM) fabrication, nanoparticle functionalization, and surface bioconjugation in research applications.

CAS Number

143-10-2

Molecular Formula

C₁₀H₂₂S₂

Molecular Weight

206.41 g/mol

Appearance

Colorless to pale yellow liquid with characteristic thiol odor

Functional Groups

Two terminal thiol (–SH) groups (bifunctional)

Key Application

Self-assembled monolayer (SAM) formation on gold and other noble metal surfaces

Storage Conditions

Store under inert atmosphere, sealed, away from light and heat sources

Chemical Identity and Physical Properties

1,10-Decanedithiol (CAS 143-10-2) is a straight-chain aliphatic dithiol with the molecular formula C₁₀H₂₂S₂ and a molecular weight of approximately 206.41 g/mol. Its systematic IUPAC name is decane-1,10-dithiol, reflecting the positions of both thiol substituents at the terminal carbons of a ten-carbon alkane backbone.

The compound is typically encountered as a colorless to pale yellow liquid at room temperature and exhibits the pungent, characteristic odor associated with organosulfur compounds. The ten-carbon hydrophobic chain confers moderate lipophilicity, while the two polar –SH termini impart hydrogen-bonding capacity and high affinity for coinage metal surfaces (Au, Ag, Cu). The molecule is sparingly soluble in water but miscible with common organic solvents such as ethanol, tetrahydrofuran, chloroform, and dimethylformamide.

The bifunctional symmetric architecture distinguishes 1,10-decanedithiol from mono-functional alkanethiols: both termini are chemically equivalent, enabling the molecule to act simultaneously as a surface anchor and a reactive tethering point for further conjugation.

Self-Assembled Monolayer (SAM) Formation

The most widely exploited property of 1,10-decanedithiol is its ability to form well-ordered self-assembled monolayers on gold and silver substrates. SAM formation proceeds through chemisorption of one thiol group onto the metal surface via an Au–S bond (bond energy approximately 40–50 kcal/mol), while the second thiol group projects away from the surface and remains available for secondary reactions.

A typical SAM deposition protocol involves immersing a freshly cleaned gold substrate (e.g., template-stripped gold or evaporated gold film) in a dilute ethanolic solution of 1,10-decanedithiol (commonly 1–10 mM) for periods ranging from several hours to overnight at room temperature under inert atmosphere or nitrogen blanket. Longer incubation times generally yield more densely packed, better-ordered monolayers with fewer defects.

The resulting monolayer exposes pendant free –SH groups at its outer surface. These reactive termini can be exploited to: (i) covalently attach nanoparticles (e.g., gold nanoparticles) through a second Au–S bond; (ii) conjugate biomolecules such as proteins or oligonucleotides via maleimide or disulfide exchange chemistries; or (iii) serve as a reactive platform for click-chemistry-based functionalization. Compared with shorter-chain dithiols, the C10 spacer provides sufficient van der Waals packing forces to stabilize the monolayer while maintaining molecular flexibility.

Research Applications

Nanoparticle Surface Functionalization: 1,10-Decanedithiol is routinely used as a bifunctional linker to assemble gold nanoparticle (AuNP) superstructures or to anchor AuNPs to planar gold surfaces for plasmonics and SERS (surface-enhanced Raman scattering) studies. One thiol adsorbs to the substrate surface while the second thiol captures solution-phase nanoparticles.

Biosensor and Electrode Modification: Dithiol-modified gold electrodes provide stable, reproducible surfaces for electrochemical biosensors. The free thiol terminus allows oriented immobilization of thiol-tagged biomolecular probes (DNA, aptamers, antibodies) without the need for additional crosslinkers, simplifying sensor fabrication.

Molecular Electronics: The well-defined length and conjugation characteristics of C10 dithiol make it a model compound in molecular junction studies, where single-molecule or few-molecule conductance is measured between two metal electrodes using STM break-junction or mechanically controllable break-junction techniques.

Crosslinking and Polymer Chemistry: As a difunctional thiol monomer, 1,10-decanedithiol participates in thiol-ene and thiol-yne click reactions to synthesize step-growth polymers, crosslinked networks, and functional hydrogels with tunable mechanical properties.

Nanoparticle Stabilization: The compound can serve as a capping ligand during or after nanoparticle synthesis to prevent aggregation and impart thiol-reactive surface functionality for downstream bioconjugation.

Handling, Safety and Storage Guidelines

Personal Protective Equipment: Handle 1,10-decanedithiol in a well-ventilated fume hood. Wear nitrile or neoprene gloves, safety goggles, and a lab coat. The compound has an unpleasant, penetrating thiol odor even at very low concentrations; avoid inhalation of vapors.

Health Hazards: Organosulfur thiols can be irritating to skin, eyes, and the respiratory tract. Consult the Safety Data Sheet (SDS) prior to use and follow institutional chemical hygiene protocols.

Storage: Store the reagent tightly sealed under an inert atmosphere (nitrogen or argon) in a cool, dark environment away from oxidizing agents. Oxidative conditions promote disulfide bond formation between –SH groups, which diminishes reactivity. Refrigerated storage (2–8 °C) is recommended for long-term stability. Avoid repeated freeze-thaw cycles.

Waste Disposal: Dispose of thiol-containing waste in accordance with local regulations for organosulfur compounds. Do not pour down the drain without neutralization or treatment.

Thiol Oxidation Monitoring: Before use, verify –SH integrity using Ellman's reagent (DTNB assay) if the reagent has been stored for extended periods or exposed to air, as partial oxidation to the disulfide will reduce effective molarity.

Frequently asked questions

What is the difference between 1,10-decanedithiol and 1-decanethiol, and when should I use each?

1-Decanethiol is a mono-functional alkanethiol with a single –SH group; it forms SAMs that present an inert hydrophobic or methyl-terminated surface. 1,10-Decanedithiol is bifunctional, presenting a reactive –SH group on both ends. Choose 1-decanethiol when you need a passivating, non-reactive SAM; choose 1,10-decanedithiol when you need the outer surface of your monolayer to remain thiol-reactive for nanoparticle capture, bioconjugation, or further chemical modification.

How do I prevent oxidation of 1,10-decanedithiol during SAM preparation?

Work quickly under an inert atmosphere (nitrogen or argon purge) and prepare solutions fresh in deoxygenated solvent (e.g., ethanol sparged with N₂ for at least 15 minutes). Keep the stock solution sealed and stored at 2–8 °C. If you suspect partial oxidation, verify thiol content with Ellman's reagent before use and discard batches showing significantly reduced –SH titer.

Can 1,10-decanedithiol be used to link gold nanoparticles into aggregates or networks?

Yes. Because both –SH groups can bind to gold surfaces, adding 1,10-decanedithiol to a colloidal gold nanoparticle suspension can crosslink particles through dual Au–S bond formation, producing controlled aggregates, dimers, or extended networks depending on the molar ratio of dithiol to nanoparticles and reaction conditions. This approach is commonly used in SERS hot-spot engineering and plasmon coupling studies.

What concentration of 1,10-decanedithiol should I use for SAM formation on gold?

Literature protocols typically use concentrations of 1–10 mM in anhydrous ethanol, with immersion times of 12–24 hours at room temperature under inert atmosphere. Lower concentrations (around 1 mM) with longer immersion times tend to produce better-ordered monolayers. Optimization may be needed depending on substrate roughness and downstream application requirements.

Is 1,10-decanedithiol compatible with thiol-ene photopolymerization?

Yes. 1,10-Decanedithiol serves as a difunctional thiol monomer in thiol-ene and thiol-yne click polymerizations initiated by UV light in the presence of a photoinitiator. Its two –SH groups enable chain extension and crosslinking, making it useful for fabricating flexible polymer networks and functional coatings.

References

1. Love, J. C.; Estroff, L. A.; Kriebel, J. K.; Nuzzo, R. G.; Whitesides, G. M. Self-Assembled Monolayers of Thiolates on Metals as a Form of Nanotechnology. Chem. Rev. 2005, 105, 1103–1169. doi:10.1021/cr0300789
2. Ulman, A. Formation and Structure of Self-Assembled Monolayers. Chem. Rev. 1996, 96, 1533–1554. doi:10.1021/cr9502357
3. Häkkinen, H. The gold–sulfur interface at the nanoscale. Nature Chem. 2012, 4, 443–455. doi:10.1038/nchem.1352
4. Hoyle, C. E.; Bowman, C. N. Thiol–Ene Click Chemistry. Angew. Chem. Int. Ed. 2010, 49, 1540–1573. doi:10.1002/anie.200903924

Products are supplied for research and development use only. Not for use in humans, animals, diagnosis, or therapy.