Stitching 2D polymeric layers into flexible interpenetrated metal-organic frameworks within single crystals

A 2D coordination polymer prepared with bulky diethylformamide solvates exhibits channels which allow dipyridyl bridging ligands to diffuse into the crystal lattice. The absorbed dipyridyls thread through the pores of one layer and substitute the surface diethylformamide molecules on the neighboring layers to stitch alternate layers to form flexible interpenetrated metal-orgaic frameworks. The threading process also results in exchange of the bulky diethylformamide solvates for aqua to minimize congestion and, more strikingly, forces the slippage of two-dimensional layers, while still maintaining crystallinity. All stitched up: Dipyridyl ligands were found to diffuse into the channels in the crystal lattice of a two-dimensional polymeric complex. The absorbed dipyridyls thread through the pores of one layer and substitute the surface solvent molecules on the neighboring layers to stitch alternate layers to form flexible interpenetrated metal-organic frameworks (see picture). © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim