Selectivity in single-molecule reactions by tip-induced redox chemistry

Area of Science:

• Surface Chemistry
• Molecular Engineering
• Redox Chemistry

Background:

• Controlling chemical reaction selectivity is a significant challenge in chemistry.
• Understanding and manipulating single-molecule reactions is crucial for developing advanced molecular devices.

Purpose of the Study:

• To demonstrate reversible and selective bond formation and dissociation using tip-induced redox reactions.
• To investigate the influence of voltage polarity and magnitude on molecular rearrangements.
• To elucidate the mechanisms underlying tip-induced selective single-molecule reactions.

Main Methods:

• Utilizing a combined scanning tunneling microscope (STM) and atomic force microscope (AFM) tip to induce and probe reactions.
• Applying controlled voltage pulses to a surface-bound molecule.
• Characterizing voltage dependence and reaction rates.
• Performing density functional theory (DFT) calculations to model reaction pathways and energy landscapes.

Main Results:

• Achieved selective constitutional isomerization by controlling voltage pulse polarity and magnitude.
• Demonstrated reversible bond formation and dissociation.
• Identified the importance of the energy landscape of different molecular charge states in determining reaction selectivity.
• Provided insights into the mechanisms of tip-induced redox reactions at the single-molecule level.

Conclusions:

• Tip-induced reduction-oxidation reactions offer a precise method for controlling molecular rearrangements.
• The energy landscape of molecular isomers in varying charge states is key to achieving selectivity.
• This work advances the understanding of redox chemistry and opens possibilities for novel molecular machines.