Scientists have developed a UV-induced method to immobilize zirconocenes onto silicon surfaces.

Johannes Khinast from Inffeldgasse, Austria and co-workers from the US, Italy and Germany have covalently attached a chiral metallocene catalyst onto H-terminated silicon surfaces using UV-induced hydrosilylation. 

Metallocenes are very active and selective catalysts for reactions such as polymerization, hydrogenation, and hydrosilylation. Achievements have been made in the area of homogeneous catalysis, as well as in the implementation of these soluble complexes in industrial applications. However, such processes are not having as much of an impact on an industrial scale as expected. 

Therefore, heterogenization (attachment onto solids) of organometallic catalysts has been of some interest for many decades. Precise spatial control of the heterogenization site cannot be achieved using common technology. In addition, homogeneous catalysts do not have the same advantages as heterogeneous catalysts, such as separation and recycling of the catalyst, prevention of metal leaching and improvement of stability.

Khinast and co-workers have focused on achieving precise and controlled heterogenization, which could lead to being implemented on an industrial scale. They have also overcome the disadvantages of homogeneous catalysts by immobilizing the metallocene onto a surface under mild reaction conditions.

This new method makes it possible to develop catalytic surfaces with a higher degree of control of the spatial structure, which may lead to the production of tuneable and structured multi-step catalytic surfaces.

Future challenges for this work include the 'sub-micron structuring of catalytic surfaces via photopatterning and photolithography, as well as the preparation of multifunctional catalysts that include organometallic and biocatalytic compounds and functionalities at the same site,' said Khinast. 

Emma Shiells