Periodic Reporting for period 2 - MolDAM (Single Molecular Devices by Atomic Manipulation)
Período documentado: 2023-04-01 hasta 2024-09-30
Breakthroughs in on-surface chemistry and characterization techniques have recently enabled the creation of novel molecules and the direct imaging of reaction intermediates at the single molecule level. Here, by employing the novel concepts of charge manipulation within molecules and coherent control of reactions by lightwave scanning tunnelling microscopy, we will bring the control and resolution of chemical reactions to an unparalleled level. We will combine our expertise in solution synthesis of dedicated organic molecules, on-surface chemistry, atom manipulation and single-molecule characterization with ultimate resolution in space and time. The combination of on-surface chemistry with charge-state control, possible by working on insulating supports, will unlock a plethora of novel charge-driven reaction pathways far from equilibrium. Employing ultrafast pulses, we aim to resolve chemical reactions with unprecedented resolution in the space and time domain unravelling the mechanisms of relevant molecular transformations. We will discover and characterize novel on-surface reactions, elusive molecules, new allotropes of carbon, intermediates and transition states and fabricate artificial molecular machines and complex molecular networks with engineered topologically protected band structures.
We demonstrated selectivity in single-molecule reactions by tip-induced redox chemistry, in a collaboration of all three groups, published in Science 377, 298–301 (2022). We obtained reversible and selective bond formation and dissociation promoted by tip-induced reduction-oxidation reactions on a surface. Molecular rearrangements leading to different constitutional isomers are selected by the polarity and magnitude of applied voltage pulses from the tip of a combined scanning tunnelling and atomic force microscope (STM/AFM). Characterization of voltage dependence of the reactions and determination of reaction rates show selectivity in constitutional isomerization reactions and provide insight into the underlying mechanisms. We found that the energy landscape of the isomers in different charge states is important to rationalize the selectivity. Tip-induced selective single-molecule reactions increase our understanding of redox chemistry and could lead to novel molecular machines. The control over the reactions and their reversibility explored in this system, also provide a promising step towards systems that would be suitable for resolving with atomic resolution chemical reactions in time.
Charge control within molecular devices on insulating supports will allow us to study electron transfer, carrier generation and recombination, redox-reactions and electroluminescence at the molecular level. Novel molecular machines will be directed by controlling single-electron charges within the device. Logic functions based on single-electron transfer will be implemented in molecular networks. Controlling and investigating these atomically defined devices on their intrinsic length and time scales will advance our fundamental understanding of the molecular world with impact on fields as diverse as chemical synthesis, light harvesting, molecular machinery and computing. In the process we expect to introduce novel synthetic procedures in the field of on-surface chemistry and single molecule reactions, as well as designing new graphene nanostructures with improved properties.