To test how the properties of structomers differ from one another, we evaluated the performance of Rh0.50Cu0.50-kofo-x (x = 2, 3, 4) structomers in gas-phase propene hydrogenation as an illustrative example 60 . Because the material composition, pore dimensions, and the primary coordination environment of Rh centers are identical, and the surface areas comparable for all three isostructural materials, the influence of the spatial correlation between Rh centers on performance could be directly tested (Fig. ). Our data shows that increasing proximity between the Rh active sites substantially accelerates propene conversion with MOP catalysts (Fig. ).