Topology of voids and channels in selected porphyrinic compounds

Porphyrinic compounds are of increasing interest to the materials science community, yet little attention has been paid to crystallographically controlled voids and channels in these materials. We have conducted an initial survey of the voids and channels in a random subset of 1000 porphyrinic compounds with known crystal structures. From calculations using a rolling-probe subroutine, we have found that about 5% of these compounds have line-of-sight channels, which differ in their topology depending on the crystallography. A small but significant number of porphyrinic compounds have calculated void contents of >25 volume %. We discuss in detail the void and channel characteristics, including pore-size distribution, of four representative compounds, with technological implications.