Supramolecular Multiporphyrin Architecture. Coordination Polymers and Open Networks in Crystals of Tetrakis(4-cyanophenyl)- and Tetrakis(4-nitrophenyl)metalloporphyrin

Crystalline solids based on the tetrakis(4-cyanophenyl) and tetrakis(4-nitrophenyl) derivatives of zinc(II)-porphyrin or copper(II)-porphyrin as building blocks have been prepared and structurally analyzed by X-ray diffraction in order to elucidate the characteristic modes of self-assembly of these functionalized moieties and evaluate the utility of such materials in a controlled design of crystalline microporous solids. In suitable crystallization environments, the cyanophenyl derivative was found to form two-dimensional coordination polymers through direct ligation of two of the -C&tbd1;N functions on each molecule to the metal centers of two neighboring porphyrins (1-3). Uniquely structured layered interporphyrin chains and networks with large cavities were observed in most of the other materials (4-9). The layered organization in the latter is dominated to a large extent by molecular shape and aromaticity of the porphyrin frameworks, while its open nature is sustained by hydrogen-bonding assisted dipolar interactions between the cyanophenyl or nitrophenyl fragments of adjacent metallomacrocyclic units. This gives rise to partly selective cocrystallization of the porphyrin material with suitably sized guest components. The discussion relates also to successful applications of other synthons for engineering polymeric and networked structures of porphyrin-based molecular solids.