Open network architectures from the self-assembly of AgNO3 and 5,10,15,20-tetra(4pyridyl)porphyrin (H(2)tpyp) building blocks: The exceptional self-penetrating topology of the 3D network of [Ag-8(Zn(II)tpyp)(7)(H2O)(2)](NO3)(8)

Very large free voids (more than 50% of the cell volume) and interesting stuctural motifs are found in the 2D and 3D frameworks assembled using AgNO3 and 5,10,15,20-tetra(4-pyridyl) porphyrin (H2tpyp) building blocks. The robust 3D network of [Ag8(ZnIItpyp)7 (H2O)2](NO3)8 is particularly fascinating in that it exhibits a unique self-penetrating topology (see figure) and can be reversibly desolvated.