Scientists in France have combined homogeneous catalysis and atomic force microscopy to create intricate surface patterns.
Atomic Force Microscopy (AFM) works by dragging a sharp tip across a material’s surface to map nanoscale surface topologies or measure surface interactions. Innovations in the design of AFM tips have allowed AFM to become a tool, not only for reading, but also for writing onto surfaces, analogous to creating tattoos on a molecular scale.
To date, AFM tips have only been able to use a narrow range of chemical transformations, including heterogeneous catalysis, to create patterns on a surface.
Now, Jean-Luc Parrain, Sylvain Clair, Olivier Chuzel and colleagues from Aix Marseille University and the National Centre for Scientific Research (CNRS), have attached a homogeneous catalyst to a commercially available AFM probe and used it to carry out alkene epoxidation at precise locations on a self-assembled monolayer. Epoxides are a commonly used synthetic handle in organic chemistry. The epoxides created on the monolayer provide ideal anchoring sites for covalent grafting of larger substrates, such as proteins, in a predefined pattern.
A wide diversity of other transformations are accessible via homogeneous catalysis. The team says the versatility of this method could make it the tool of choice for scientists wanting to perform organic reactions in complex patterns on surfaces. Jurriaan Huskens, chair of the molecular nanofabrication group at the University of Twente, the Netherlands, says ‘it is a potentially powerful strategy’.
Huskens adds that the field of nanolithography should be challenged to find applications that make good use of the beautifully designed surfaces being produced. The team have exciting plans to develop their system to create sophisticated surfaces for molecular electronics.