Related Experiment Video
Updated: Jul 9, 2026
10:37
Spatial Separation of Molecular Conformers and Clusters
Published on: January 9, 2014
Spatially controlled Suzuki and Heck catalytic molecular coupling
Jason J Davis1, Claire B Bagshaw, Katerina L Busuttil
1Department of Chemistry, University of Oxford, Chemistry Research Laboratory, Mansfield Road, OX1 3TA, UK. jason.davis@chem.ox.ac.uk
Journal of the American Chemical Society
|October 26, 2006
Summary
Researchers used a palladium-modified atomic force microscope (AFM) probe to precisely control surface-confined Suzuki and Heck coupling reactions. This method enables "chemically written reactions" at the nanoscale for advanced nanofabrication.
Area of Science:
- Nanotechnology and Materials Science
- Surface Chemistry and Catalysis
- Atomic Force Microscopy (AFM) Applications
Background:
- Bottom-up nanofabrication requires precise control over chemical reactions at the nanoscale.
- Surface-confined carbon-carbon coupling reactions are crucial for building complex molecular structures.
- Existing methods often lack the spatial resolution and control needed for intricate nanoscale patterning.
Purpose of the Study:
- To demonstrate the use of a catalytically active AFM probe for initiating and controlling surface-confined coupling reactions.
- To achieve high-resolution chemical patterning using palladium-catalyzed organometallic reactions.
- To quantify reaction rates and efficiency at the subzeptomolar level.
Main Methods:
- Utilized a palladium-modified AFM probe as a catalyst to initiate Suzuki and Heck coupling reactions.
- Spatially controlled reactions by scanning the AFM probe across the substrate surface.
- Detected and characterized the patterned reactions using lateral force microscopy and chemical-specific labeling.
Main Results:
- Achieved spatially controlled surface-confined Suzuki and Heck carbon-carbon coupling reactions with line widths down to 15 nm.
- Demonstrated 'chemically written reactions' at subzeptomolar levels, equivalent to approximately 20 molecules per pattern.
- Resolved turnover numbers of (0.6-1.2) x 10^4 molecules s^-1 for Suzuki and (3.0-5.0) x 10^4 molecules s^-1 for Heck reactions.
Conclusions:
- A palladium-modified AFM probe enables precise initiation and spatial control of surface-confined coupling reactions.
- This technique allows for nanoscale chemical patterning with high resolution and efficiency.
- The method offers a powerful tool for bottom-up nanofabrication and studying catalytic reactions at the molecular level.
Related Concept Videos
03:24Hybridization of Atomic Orbitals I
The mathematical expression known as the wave function, ψ, contains information about each orbital and the wavelike properties of electrons in an isolated atom. When atoms are bound together in a molecule, the wave functions combine to produce new mathematical descriptions that have different shapes. This process of combining the wave functions for atomic orbitals is called hybridization and is mathematically accomplished by the linear combination of atomic orbitals. The new orbitals that...
03:51Molecular Orbital Theory II
Molecular Orbital Energy Diagrams
02:36Regioselectivity and Stereochemistry of Hydroboration
A significant aspect of hydroboration–oxidation is the regio- and stereochemical outcome of the reaction.
Hydroboration proceeds in a concerted fashion with the attack of borane on the π bond, giving a cyclic four-centered transition state. The –BH2 group is bonded to the less substituted carbon and –H to the more substituted carbon. The concerted nature requires the simultaneous addition of –H and –BH2 across the same face of the alkene giving syn stereochemistry.
Hydroboration proceeds in a concerted fashion with the attack of borane on the π bond, giving a cyclic four-centered transition state. The –BH2 group is bonded to the less substituted carbon and –H to the more substituted carbon. The concerted nature requires the simultaneous addition of –H and –BH2 across the same face of the alkene giving syn stereochemistry.
01:58Cooperative Allosteric Transitions
Cooperative allosteric transitions can occur in multimeric proteins, where each subunit of the protein has its own ligand-binding site. When a ligand binds to any of these subunits, it triggers a conformational change that affects the binding sites in the other subunits; this can change the affinity of the other sites for their respective ligands. The ability of the protein to change the shape of its binding site is attributed to the presence of a mix of flexible and stable segments in the...
01:23Electrophilic Addition of HX to 1,3-Butadiene: Thermodynamic vs Kinetic Control
The addition of a hydrogen halide to 1,3-butadiene gives a mixture of 1,2- and 1,4-adducts. Since more substituted alkenes are more stable, the 1,4-adduct is expected to be the major product. However, the product distribution is strongly influenced by temperature; low temperature favors the 1,2-adduct, whereas the 1,4-adduct is predominant at high temperature.
01:22Heterogeneous Catalysis
Heterogeneous catalysis involves a catalyst in a different phase from the reactants. It is a process where the catalyst and the reactants are in distinct phases, typically solid and gas or liquid.Most heterogeneous catalysts are metals, metal oxides, or acids. The list includes transition metals like iron (Fe), cobalt (Co), nickel (Ni), palladium (Pd), platinum (Pt), chromium (Cr), manganese (Mn), tungsten (W), silver (Ag), and copper (Cu). These metals possess partially vacant d orbitals that...