Two- and three-fold interpenetrated metal-organic frameworks from one-pot crystallization

Abstract

Two different three-dimensional interpenetrating metal-organic frameworks, {[Co(bpe)(muco)](DMF)(H2O)}n (1) and {[Co(bpe)(muco) (H2O)2]·4(H2O)}n (2) [bpe = 4,4′-bipyridyl ethylene, H2-muco = trans,trans-muconic acid, DMF = dimethyl formamide] have been co-crystallized in one-pot reaction. This work offers some insights into the intricacy of designing coordination polymers with variable interpenetration, showing new modes of entanglements. Single crystal X-ray diffraction analyses reveal that the compound 1 has a highly distorted cubic (α-Po) net with 2-fold interpenetrated structures while compound 2 displays a 3-fold interpenetrating net-work with an unprecedented 66 topology which is different from other well-known 4-connected nets such as diamond or hexagonal diamond. Despite varied interpenetrations, both compounds retain open channels, filled with aggregated guest solvent molecules. As far as the ratios of Co/muco/bpe are concerned, these two complexes can be considered as supramolecular isomers. Formation of a particular isomer in major quantity can be obtained by varying the countercation of the muconate salt in different solvents, by layering, and by changing the order of the components. © 2008 American Chemical Society.