ASSEMBLY OF PORPHYRIN BUILDING-BLOCKS INTO NETWORK STRUCTURES WITH LARGE CHANNELS

CRYSTAL engineering-the deliberate design and construction of crystal structures from molecular components-promises to provide solid-state materials with specific and useful chemical, mechanical, electronic or optical properties(1). In most of the molecular crystals considered so far, van der Waals forces and hydrogen bonding govern the crystal packing(2-7). Zeolites, pillared clays and related microporous materials, which have been studied extensively because their porous structures convey useful catalytic activity(8,9), can now also be 'engineered' to some extent(10,11). We are exploring ways(12-14) to construct channelled solids with very different chemical cal architectures and potentially different catalytic activity from those of zeolites. Here we show that porphyrin building blocks can be used to construct three-dimensional networks with the topology of the PtS structure, containing large channels. In our materials the channels are filled with solvent molecules, and crystalline order is lost on solvent removal. Nevertheless, the results show that it is possible to use simple molecular building blocks to engineer specific frameworks which, if they can be made robust, may offer new catalytic potential.