Stitching 2D Polymeric Layers into Flexible Interpenetrated Metal–Organic Frameworks within Single Crystals

Abstract

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.

A Single-Crystal to Single-Crystal Conversion Scheme for a Two-Dimensional Metal–Organic Framework Bearing Linear Cd3 Secondary Building Units

“…These MOFs (with the exception of 6d) exhibited type I CO 2 adsorption profiles with a steep uptake in the lowpressure region (Figure 2 and Figure S9), consistent with the presence of open channels in the degassed phase. 25 The CO 2 adsorption isotherms for 3, 4, 5, 6a−6c, 6e, and 7b also exhibited different degrees of hysteresis upon desorption, reflecting the framework flexibility and/or an extra interaction between the framework and CO 2 . 16 The inability of these MOFs to absorb N 2 (kinetic size 3.64 Å; quadruple moments of 1.52 × 10 −26 esu cm 2 ) and low capacity for CO 2 (kinetic size 3.30 Å; 4.30 × 10 −26 esu cm 2 ) 36,37 are likely due to the cracking of crystals upon activation.…”