"The development of new approaches in transition metal catalysis is of utmost importance since it provides the future tools required to arrive at a sustainable society. Interestingly, the field of transition metal catalysis has been dominated by the relatively simple dogma that the activity and the selectivity of the catalyst is determined by the interplay between the metal and the ligands that are coordinated to the metal. By developing new ligands, new catalyst can be uncovered that display specific reactivity and selectivity. Nature on the other hand, uses a much larger tool-box to arrive at catalytic systems that are generally far more active and selective than the man-made catalysts. Enzymes often use multimetallic sites, or multi functional groups that work in concert. Importantly, Enzymes are much larger than synthetic catalysts, and take advantage of the second sphere around an active site by 1) creating a sterically constrained cavity around it leading to entatic states, i.e. deformed intermediate states that lead to lower energy barriers to the product 2) positioning functional groups within the cavity to properly orient and activate the substrate, by lower the transition state via secondary interactions.In the current proposal we control catalyst properties by encapsulation. Will will use isolated natural active sites (and models theirof) and install these in well-defined cavities and study their properties. Can we create a second coordination sphere such that we can get activities and selectivies similar to that of the original enzyme? For example, we aim for nitrogenase activity by putting isolated active sites in synthetic cages."