A Zn(II)-based pillar-layered metal–organic framework: Synthesis, structure, and CO2 selective adsorption

Carbon dioxide separation and capture by adsorption: a review

Rising adverse impact of climate change caused by anthropogenic activities is calling for advanced methods to reduce carbon dioxide emissions. Here, we review adsorption technologies for carbon dioxide capture with focus on materials, techniques, and processes, additive manufacturing, direct air capture, machine learning, life cycle assessment, commercialization and scale-up.

Enhanced Antibacterial Potential of Amoxicillin against Helicobacter pylori Mediated by Lactobionic Acid Coated Zn-MOFs

H. pylori (Helicobacter pylori) causes a common chronic infectious disease and infects around 4.4 billion people worldwide. H. pylori was classified as a member of the primary class of stomach cancer (stomach adenocarcinoma). Hence, this study was conducted to design a novel lactobionic acid (LBA)-coated Zn-MOFs to enhance bactericidal activity of Amoxicillin (AMX) against H. pylori. The synthesized Zn-MOFs were characterized by various techniques which included Dynamic Light Scattering (DLS), Fourier Transform Infrared (FT-IR) Spectroscopy, Powder X-ray diffraction, scanning electron microscope, and atomic force microscope. They were capable of encapsulating an increased amount of AMX and investigated for their efficacy to enhance the antibacterial potential of their loaded drug candidate. Interestingly, it was found that LBA-coated Zn-MOFs significantly reduced the IC₅₀, MIC, and MBIC values of AMX against H. pylori. Morphological investigation of treated bacterial cells further authenticated the above results as LBA-coated Zn-MOFs-treated cells underwent complete distortion compared with non-coated AMX loaded Zn-MOFs. Based on the results of the study, it can be suggested that LBA-coated Zn-MOFs may be an effective alternate candidate to provide new perspective for the treatment of H. pylori infections.

Modulation of CO2 adsorption in novel pillar-layered MOFs based on carboxylate-pyrazole flexible linker

Metal-organic frameworks (MOFs) have attracted significant attention as sorbents due to their high surface area, tunable pore volume and pore size, coordinatively unsaturated metal sites, and ability to install desired functional groups by post-synthetic modification. Herein, we report three new MOFs with pillar-paddlewheel structures that have been synthesized solvothermally from the mixture of the carboxylate-pyrazole flexible linker (H₂L), 4,4-bipyridine (BPY)/triethylenediamine (DABCO), and Zn(ii)/Cu(ii) ions. The MOFs obtained, namely [Zn^II(L)BPY], [Cu^II(L)BPY], and [Cu^II(L)DABCO], exhibit two-fold interpenetration and dinuclear paddle-wheel nodes. The Zn(ii)/Cu(ii) cations are coordinated by two equatorial L linkers that result in two-dimensional sheets which in turn are pillared by BPY or DABCO in the perpendicular direction to obtain a neutral three-dimensional framework that shows one-dimensional square channels. The three pillar-layered MOFs were characterized as microporous materials showing high crystalline stability after activation at 120 °C and CO₂ adsorption. All MOFs contain uncoordinated Lewis basic pyrazole nitrogen atoms in the framework which have an affinity toward CO₂ and hence could potentially serve as CO₂ adsorption material. The CO₂ uptake capacity was initially enhanced by replacing Zn with Cu and then replacing the pillar, going from BPY to DABCO. Overall, all the MOFs exhibit low isosteric heat (Q_st) of adsorption which signifies an advantage due to the energy required for the adsorption and regeneration processes.

Highly selective sensing of Fe3+/Hg2+ and proton conduction using two fluorescent Zn(ii) coordination polymers

A pair of homologues, [Zn(Hssa)(1,4-bib)·H2O]n (1) and [Zn3(ssa)2(1,4-bib)3·4H2O]n (2), were successfully assembled using the same metals and ligands [H3ssa = 5-sulfosalicylic acid; 1,4-bib = 1,4-bis(1H-imidazol-1-yl)benzene] under solvothermal conditions. Polymer 1 is a two-dimensional (2D) sql network and polymer 2 is a three-dimensional (3D) framework. Polymer 2 can be simplified into two topology types: bct and tfc. The two polymers show significant differences in the fluorescence sensing of metal ions and proton conductivity. Their applications in detecting metal ions and proton conductivity were explored. Polymer 1 shows high sensitivity and selectivity for Fe3+, while polymer 2 can detect Hg2+ ions. The limit of detection was 1.66 μM with Fe3+ for 1 and 0.23 μM with Hg2+ for 2 in water. In addition, both 1 and 2 exhibit high water stability and proton conductivity. At 60 °C and 95% relative humidity, their conductivities were 3.45 × 10-5 and 6.26 × 10-6 S cm-1, respectively. A detailed analysis of the Hirshfeld surface and fingerprints was carried out for 1 and 2 to compare the interactions between the molecules, which is essential for analysing the relationship between their structures and material properties.