Interpenetrated three-dimensional hydrogen-bonded networks from metal-organic molecular and one- or two-dimensional polymeric motifs

The occurrence of interpenetrated three-dimensional networks has been systematically investigated by the analysis of the crystallographic structural databases, using the program package TOPOS. After our previous reports on interpenetration observed in valence-bonded MOFs, inorganic arrays and hydrogen-bonded organic supramolecular architectures, in this paper we have focused our research on the interpenetrated 3D networks based on hydrogen-bonded metal-organic molecular (0D) and polymeric (1D and 2D) complexes from the Cambridge Structural Database. The current interest for the crystal engineering of new functional materials has prompted many research groups to adopt synthetic strategies implying the use of molecular metal complexes (0D) with suitably exo-oriented hydrogen-bond donor and acceptor groups for the assembly of extended networks. With regard to this we have examined 3D hydrogen-bonded supramolecular arrays formed by finite and infinite motifs of lower dimensionality, analyzing their topologies and looking for their entanglements. We have extracted a comprehensive list including 135 different motifs (71 assembled from 0D, 43 from 1D and 21 from 2D metal-organic motifs) showing the phenomenon of interpenetration (about two thirds not detected in the original papers). These hydrogen-bonded networks include species assembled by one or more building blocks, that are classified within the previously introduced Classes of interpenetration. It is observed that the maximum interpenetration degree is limited to 5-fold and the main (overall) topology is 4(12).6(3)-pcu. An analysis of the possible relationships between the dimensionality of the building blocks and the resulting network connectivity and topology, and of some factors determining the interpenetration is also attempted, together with a comparison of the present results with those for other families of interpenetrated materials.