Hong-Ru Fu

Highly Selective and Sensitive Trimethylamine Gas Sensor Based on Cobalt Imidazolate Framework Material

A cobalt imidazolate (im) framework material [Co(im)2]n was employed to use as a trimethylamine (TMA) gas sensor and the [Co(im)2]n sensor can be easily fabricated by using Ag-Pd interdigitated electrodes. Gas sensing measurement indicated that the [Co(im)2]n sensor shows excellent selectivity, high gas response and a low detection limit level of 2 ppm to TMA at 75 °C. The good selectivity and high response to TMA of the sensor based on [Co(im)2]n may be attributed to the weak interaction between the TMA molecules and the [Co(im)2]n framework. That may provide an ideal candidate for detecting freshness of fish and seafood.

Porous ctn-type boron imidazolate framework for gas storage and separation.

BIFing it up: The assembly between triangular HB(mim)3 units and tetrahedral Zn centers (see graphic) leads to the formation of a ctn-type BIF material with high porosity for gas storage and separation (mim = 2-methylimidazolate).

Homochiral Metal–Organic Frameworks with Enantiopure Proline Units for the Catalytic Synthesis of β-Lactams

Two enantiopure organic ligands integrating flexible proline units and rigid isophthalate units have been rationally designed and employed for the construction of four homochiral porous metal-organic frameworks (MOFs), respectively. One pair of these MOFs is used as heterogeneous catalysts to construct β-lactam derivatives by oxidative coupling reactions.

Size-Dependent Enantioselective Adsorption of Racemic Molecules through Homochiral Metal-Organic Frameworks Embedding Helicity.

Homochiral metal-organic frameworks (HMOFs) are efficient materials for enantioselective adsorption. However, the combination of size selectivity and enantioselectivity is still a major challenge in the field of HMOFs. Herein, two enantiomorphic HMOFs built from predesigned proline-derived ligands are presented. Both of them show multiple homochiral features: they contain four different helical chains and three types of helical channels. Due to the size effect of the helical channels, each HMOF can enantioselectively adsorb methyl lactate with high ee. The results reveal a new approach toward size-dependent enantioselective separation of racemic compounds by using HMOFs built from inexpensive proline derivatives.

Selective Sorption of Light Hydrocarbons on a Family of Metal–Organic Frameworks with Different Imidazolate Pillars

Four isostructural pillared-layer metal-organic frameworks (as 1-ims series) are successfully synthesized via the charge-balance approach, where trigonal [Zn2(CO2)3] cluster-based cationic layers [Zn2(NH2-BTB)](+) (NH2-H3BTB = 1,3,5-(3-benzoic acid) aniline) are connected by a series of 2-substituted imidazolates. The 1-ims supply a systematic platform to explore the adsorption of light hydrocarbons. Especially, 1-ims shows good adsorption selectivity of C3/C1 and C2/C1, and the selectivities of C3H8/CH4 are all over 100 at room temperature. These results demonstrate that introduction of functional group plays a key role on tuning the channel and pore size as well as improving the adsorption selectivity.

Stable dye-encapsulated indium–organic framework as dual-emitting sensor for the detection of Hg2+/Cr2O72− and a wide range of nitro-compounds

A water-stable porous anionic metal–organic framework (MOF), [(CH3)2NH2][In(TNB)4/3]·(2DMF)(3H2O) (1, H3TNB = 4,4′,4′′-nitrilotribenzoicacid), was synthesized. Through ion-exchange method, one dual-emitting composite 1⊃DSM was prepared with the encapsulation of cationic dye 4-[p-(dimethylamino)styryl]-1-ethylpyridinium (DSM). 1⊃DSM exhibits sensitive quenching response towards Hg2+ and Cr2O72− ions in aqueous solution. In particular, the detection limit of Hg2+ is as low as 1.75 ppb, which is among the lowest values for MOF-based probes. Moreover, 1⊃DSM shows remarkable sensitivity for nitro-explosives in a wide scope, particularly for phenol hydroxyl-containing nitro-explosives. Furthermore, 1⊃DSM has a broad response to nitroimidazole-based antibiotics at low concentrations. As a result, the incorporation of DSM into MOF could strikingly improve the sensitivity and range of the detection. In addition, the orbital energy theoretical calculation and UV-Vis absorption experiments confirmed that the quenching performances could be mainly attributed to the electron transfer and resonance energy transfer effect between the framework, DSM and the analytes.

Dual-Emission SG7@MOF Sensor via SC–SC Transformation: Enhancing the Formation of Excimer Emission and the Range and Sensitivity of Detection

In this study, a water stable metal-organic framework FIR-53 is applied as a single-crystal container for anion exchange. The exceptional chemical stability and low crystallographic symmetry of FIR-53 makes it possible to determine anionic guests. Through ion exchange and single-crystal to single-crystal (SC-SC) transformation, 8-hydroxypyrene-1,3,6-trisulfonate (SG7, solvent green 7, ion form as SG73-) is introduced into the pores of FIR-53 to obtain SG7@FIR-53. Because of the spatial confinement and partition effect, SG7@FIR-53 shows the bright exciter emission of SG7 ions. Interestingly, the composite SG7@FIR-53 exhibits a sensitive fluorescence quenching response against Cr2O72- and MnO4- in aqueous solution. Especially, the detection limit toward MnO4- is as low as 0.12 ppb, which is the smallest value to date. Moreover, the prepared SG7@FIR-53 film also displays a broad response to nitro explosives in vapor/aqueous phase. Compared with the results of FIR-53, the range and sensitivity were greatly improved.