TETRAARYLPORPHYRIN SPONGES - COMPOSITION, STRUCTURAL SYSTEMATICS, AND APPLICATIONS OF A LARGE CLASS OF PROGRAMMABLE LATTICE CLATHRATES

A survey of tetraphenylporphyrins and metallotetraphenylporphyrins reveals that in the solid state many of these compounds adopt a common mode of molecular packing that resembles a simple body-centered-cubic arrangement. The intersecting channels characteristic of this lattice can accommodate a wide range of ligand and solvate “guest” molecules. In this sense, these materials resemble sponges with microscopic pores. Because the axial coordination sites of metalloporphyrin metal atoms are directed into the open channels, these metal atoms can adopt 4-, 5-, or 6-coordinate geometries. Represented in this class are metalloporphyrins with 0, +2, +3, +4, and +5 metal atom oxidation states, as well as free porphyrins with two hydrogen atoms replacing the metal atom. Mixed crystals can be prepared in which the various coordination types and oxidation states coexist. In some such crystals, different chemical species exist in dynamic equilibrium. Simple applications of these materials involve their use to crystallize substances that would otherwise be difficult to obtain in an ordered solid. More sophisticated applications exploit the fact that a host lattice based on materials in this series can be easily tailored to accommodate guests of a predetermined size, shape, handedness, and charge. Structural data are provided for 20 previously unpublished materials. © 1990, American Chemical Society. All rights reserved.