Tandem Catalysis with Thin Films

  • ChemPubSoc Europe Logo
  • Author: ChemPlusChem
  • Published Date: 25 April 2016
  • Source / Publisher: ChemPlusChem/Wiley-VCH
  • Copyright: Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
thumbnail image: Tandem Catalysis with Thin Films

Related Societies

In nature, complex molecules arise from catalytic enzymatic processes that take place in close proximity to one another. The product from one enzyme-catalyzed transformation can be shunted efficiently to the next enzyme without losses due to dispersal or degradation.


One strategy for mimicking this synthetic approach is to incorporate multiple artificial catalysts in one robust structure. Because of their diverse and tunable structures, high surface area, and porous nanoscale channels, metal-organic frameworks (MOFs) are promising both as heterogeneous supports and as hosts for the integration of homogeneous catalysts. However, most MOFs contain only a single type of catalytically active site.


Omar Farha, Joseph T. Hupp, and colleagues, Northwestern University, Evanston, IL, USA, have assembled a MOF containing two types of catalytic species. The team used a stepwise approach such that these catalyst sites are precisely positioned, yet safely isolated from each other in a single architecture. The functional MOF is composed of Robust Porphyrinic Material (RPM) with a pillared-paddlewheel topology. The MOF features Mn porphyrins and Zn porphyrins in an orthogonal arrangement forming large 3D channels (pictured).


This material can be used to perform a tandem reaction: 1) the Mn porphyrin catalyzes the epoxidation of an olefin substrate and 2) the Zn porphyrin catalyzes epoxide opening and the insertion of CO2. The RPMā€“MOF was also prepared in a layer-by-layer fashion as a porous and ultrathin film on a self-assembled-monolayer-coated silicon platform. When deployed as a tandem catalyst, the film version displays substantially higher catalytic turnover than that achieved with bulk crystalline MOF samples. This reflects the optimal diffusion of the reactants to the catalyst active sites in the ultrathin film. Catalysts for other tandem reactions should also be accessible by this approach.


 

Article Views: 2046

Sign in Area

Please sign in below

Additional Sign In options

Please note that to comment on an article you must be registered and logged in.
Registration is for free, you may already be registered to receive, e.g., the newsletter. When you register on this website, please ensure you view our terms and conditions. All comments are subject to moderation.

Article Comments - To add a comment please sign in

Bookmark and Share

If you would like to reuse any content, in print or online, from ChemistryViews.org, please contact us first for permission. more


CONNECT:

ChemistryViews.org on Facebook

ChemistryViews.org on Twitter ChemistryViews.org on YouTube ChemistryViews.org on LinkedIn Sign up for our free newsletter


A product of ChemPubSoc Europe (16 European Chemical Societies)and Wiley-VCH