Internal metal center, design

So far, catalyst design has aimed mainly at oxidant activation and little attention has been paid to the interaction between the metal center and the alkene. A requirement for a successful epoxidation system of wide scope for simple terminal alkenes would seem to be a new catalyst design focusing on activation of the substrate instead of the oxidant. This suggests noble metals as applicable catalytic centers, because of their affinity for terminal alkenes versus internal ones. This results in a change of role for the catalyst from electrophile to nucleophile in the system. 

The coordination of PyPs to metal fragments can be performed using them either as free-bases (i.e. with no metal inserted in the internal core) or as metallated units. Alternatively, inner metal centers can be introduced in a second step, after external coordination, depending on the design rationale. The presence of one or more metalloporphyrin imits in the final assembly, in addition to introducing novel reactive functionalities (i.e. the inner metal ions), can vary dramatically its photophysical properties. 

In the TP design of Figure 5.2a, individual grids are etched metal with parallel wires of 0.05 mm diameter at distances of 0.5 mm center to center. The wires, with rectangular cross section, span a circular cross section with an internal diameter of 13 mm on a disk with a 30 mm outer diameter. The two grids were separated by... 

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