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A laboratory experiment that involves the synthesis, characterization, and application exploration of a metal-organic framework (MOF) has been developed for first-year undergraduates in the Faculty of Engineering at National University of Singapore. The desired MOF material was prepared from commercially available reagents in a facile stirring-assisted synthetic method with minimal safety concerns. In order to ensure that the whole experiment could be finished within a regular 3 h lab session, the corresponding commercial MOF material was used for characterization and application studies. Specifically, a powder X-ray diffractometer (PXRD) was adopted to evaluate the crystallinity of the commercial MOF material. Moreover, the potential of this MOF material for real-life applications was exemplified by the ability of its commercial counterpart for the selective dye removal from aqueous solutions. This laboratory experiment offers the opportunity for instructors to introduce first-year undergraduates without a specific background in chemistry or materials science to state-of-the-art advanced porous materials, a modern characterization instrument, and the broader impacts of materials chemistry.

Solid‐state hybrid materials with designability in topology and tunable photo‐responsiveness hold great promise for multitudinous applications from optoelectronics to information storage/communication. However, the judicious design and synthesis of metal–organic frameworks (MOFs) with intrinsically custom‐made nonlinear optical (NLO) properties including multiple photon absorption and harmonic generation effects suitable for miniaturized devices remain highly challenging. Herein, the design and synthesis of a novel pillared framework named after Zn‐TCPE‐DPNI MOF coordinated by zinc ions (Zn2+), aggregation induced emission (AIE) featured [1,1′‐biphenyl]‐4‐carboxylic acid (H4TCPE), and N,N′‐di(4‐pyridyl)‐1,4,5,8‐naphthalenetetracarboxydiimide (DPNI) are reported. The highly ordered Zn‐TCPE‐DPNI MOF single crystal exhibits tunable NLO responses by switching incident excitation wavelengths of a femtosecond laser from 900 to 1500 nm. The noticeable transformation from two‐ or three‐photon excited photoluminescence (2PL or 3PL) to the concurrent occurrence of 3PL and third harmonic generation (THG), and eventually to the mere emergence of THG with a high effective susceptibility χ(3) (3ω) of 2.9 × 10−12 esu is observed. This study paves a novel avenue for the design and synthesis of photoluminescent MOF crystals with tunable NLO responses toward the fabrication of multifunctional NLO devices targeted for optoelectronics and information communication. [ABSTRACT FROM AUTHOR]

Membrane technology is attractive for natural gas separation (removing CO 2 , H 2 O, and hydrocarbons from CH 4 ) because of membranes' low energy consumption and small environmental footprint. Compared to polymeric membranes, microporous inorganic membranes such as silicoaluminophosphate-34 (SAPO-34) membrane can retain their separation performance under conditions close to industrial requirements. However, moisture and hydrocarbons in natural gas can be strongly adsorbed in the pores of those membranes, thereby reducing the membrane separation performance. Herein, we report the fabrication of a polycrystalline MIL-160 membrane on an Al 2 O 3 substrate by in situ hydrothermal synthesis. The MIL-160 membrane with a thickness of ca. 3 μm shows a remarkable molecular sieving effect in gas separation. Besides, the pore size and environment of the MIL-160 membrane can be precisely controlled using reticular chemistry by regulating the size and functionality of the ligand. Interestingly, the more polar fluorine-functionalized multivariate MIL-160/CAU-10-F membrane exhibits a 10.7% increase in selectivity for CO 2 /CH 4 separation and a 31.2% increase in CO 2 permeance compared to those of the MIL-160 membrane. In addition, hydrophobic MIL-160 membranes and MIL-160/CAU-10-F membranes are more resistant to water vapor and hydrocarbons than the hydrophilic SAPO-34 membranes.

The self-assembly of highly stable zirconium(IV)-based coordination cages with aggregation induced emission (AIE) molecular rotors for in vitro bio-imaging is reported. The two coordination cages, NUS-100 and NUS-101, are assembled from the highly stable trinuclear zirconium vertices and two flexible carboxyl-decorated tetraphenylethylene (TPE) spacers. Extensive experimental and theoretical results show that the emissive intensity of the coordination cages can be controlled by restricting the dynamics of AIE-active molecular rotors though multiple external stimuli. Because the two coordination cages have excellent chemical stability in aqueous solutions (pH stability: 2-10) and impressive AIE characteristics contributed by the molecular rotors, they can be employed as novel biological fluorescent probes for in vitro live-cell imaging., (© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)