Solvent‐Controlled Construction of Molecular Chains and Bowls/Sieves from a Bent Dipyridyl Ligand^†

Abstract

Main observation and conclusion Solvothermal reactions of 3,6‐di(pyridin‐4‐yl)‐9H‐carbazole (dpc) with Cu(II) yielded crystals of two new coordination complexes, namely [Cu(CH3COO)2(dpc)(H2O)2]n·xGuest (1) and [Cu13(HCOO)16(dpc)16(H2O)6](HCOO)10·Guest (2), in which CH3COO– and HCOO– were generated from the hydrolysis of the solvents N,N‐dimethylacetamide (DMA) and N,N‐dimethylformamide (DMF), respectively. Single‐crystal X‐ray diffraction showed that 1 possesses simple wavy coordination chains, while 2 possesses large molecular bowls/sieves with outer and inner effective sizes of 30.2 × 30.2 × 25.5 Å3 and 15.0 × 15.0 × 18.6 Å3, respectively, which consists of 4 linear Cu3(HCOO)4(H2O) clusters and 12 dpc ligands as the square‐shaped wall and a claw‐like Cu(dpc)4 fragment as the bottle. Guest‐free 2 can adsorb considerable amounts of CO2, H2O and CH3OH but completely exclude C2H4 and C3H6, which shows a potential application for olefin drying.

A gating ultramicroporous metal-organic framework showing high adsorption selectivity, capacity and rate for xylene separation

“…While many thermodynamic, kinetic, and even molecularsieving separation mechanisms have been reported [23][24][25][26], only ultramicropores with sizes similar to that of pX achieved high pX selectivity over 10 [2,3,21,22,27-34]. The size/shape-matched pores can achieve better guest recognition, while the ultra-small pore apertures enlarge the difference of guest adsorption/diffusion rates through the gating mechanism (transisent opening/closing of relatively small pore apertures), although these structural responses are often ignored due to the difficulty of characterization [22,23,[35][36][37][38][39]. However, such adsorbents generally possess discrete (0D) or one-dimensional (1D) pores with low porosities (void ratio < 20%) and high gating barriers (relatively rigid), giving low adsorption capacities (< 2.0 mmol g −1…”