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We report the inaugural experimental investigation of covalent organic frameworks (COFs) to address the formidable challenge of SO2 detection. Specifically, an imine-functionalized COF (SonoCOF-9) demonstrated a modest and reversible SO2 sorption of 3.5 mmol g-1 at 1 bar and 298 K. At 0.1 bar (and 298 K), the total SO2 uptake reached 0.91 mmol g-1 with excellent reversibility for at least 50 adsorption-desorption cycles. An isosteric enthalpy of adsorption (ΔHads) for SO2 equaled -42.3 kJ mol-1, indicating a relatively strong interaction of SO2 molecules with the COF material. Also, molecular dynamics simulations and Møller-Plesset perturbation theory calculations showed the interaction of SO2 with π density of the rings and lone pairs of the N atoms of SonoCOF-9. The combination of experimental data and theoretical calculations corroborated the potential use of this COF for the selective detection and sensing of SO2 at the sub-ppm level (0.0064 ppm of SO2)., (© 2024 Wiley‐VCH GmbH.)

The Al(III)-based MOF CYCU-3 exhibits a relevant SO 2 adsorption performance with a total uptake of 11.03 mmol g -1 at 1 bar and 298 K. CYCU-3 displays high chemical stability towards dry and wet SO 2 exposure. DRIFTS experiments and computational calculations demonstrated that hydrogen bonding between SO 2 molecules and bridging Al(III)-OH groups are the preferential adsorption sites. In addition, photoluminescence experiments demonstrated the relevance of CYCU-3 for application in SO 2 detection with good selectivity for SO 2 over CO 2 and H 2 O. The change in fluorescence performance demonstrates a clear turn-on effect after SO 2 interaction. Finally, the suppression of ligand-metal energy transfer along with the enhancement of ligand-centered π* → π electronic transition was proposed as a plausible fluorescence mechanism.

CsPbBr 3 nanocrystals (NCs) are promising optoelectronic and catalytic materials. Manipulating their morphology can improve their properties and stability. In this work, an alkene-derived zwitterionic ligand was used to control the morphology of CsPbBr 3 NCs to yield the highly unusual rhombicuboctahedron morphology, showcasing the first example of a surfactant-tail controlled growth.

The MOF-type Ni 2 (dobpdc) shows a high chemical stability towards SO 2 , high capacity for SO 2 capture at low pressure (4.3 mmol g -1 at 298 K and up to 0.05 bar), and exceptional cycling performance. Fluorescence experiments demonstrated the SO 2 detection properties of Ni 2 (dobpdc) with a remarkable SO 2 detection selectivity. Finally, time-resolved photoluminescence experiments provided a plausible mechanism of SO 2 detection by this Ni(II)-based MOF material.

Modulated self-assembly protocols are used to develop facile, HF-free syntheses of the archetypal flexible PCP, MIL-53(Cr), and novel isoreticular analogues MIL-53(Cr)-Br and MIL-53(Cr)-NO 2 . All three PCPs show good SO 2 uptake (298 K, 1 bar) and high chemical stabilities against dry and wet SO 2 . Solid-state photoluminescence spectroscopy indicates all three PCPs exhibit turn-off sensing of SO 2 , in particular MIL-53(Cr)-Br, which shows a 2.7-fold decrease in emission on exposure to SO 2 at room temperature, indicating potential sensing applications.

We report a practical two-step approach involving a Ugi 4-CR/ azide-alkyne cycloaddition for the synthesis of biaryl-containing cyclophanes. The series represents an extension of our previously reported macrocycles as an effort to enhance the anti-proliferative activity of this scaffold. In this variant, we incorporate a biphenyl moiety in the framework, thus enhancing the macrocycle size, lipophilicity, and structural diversity. Macrocycles were tested against different cell lines, being more cytotoxic against prostate (PC-3 and DU-145) and breast (MCF-7) tumor cells. Gratifyingly, the most active compound showed a significative enhancement of PC-3 growth inhibition with respect to our previous series, reaffirming the potential anti-proliferative activity of this kind of cyclophanes., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

We demonstrate here that the Ugi-Sonogashira protocol can be successfully used to obtain five new molecular rotors 10a-e with strong emission. They have been synthesized by combining multicomponent Ugi stators and several aromatic rotary components: phenylene, p-xylene, naphthalene and anthracene. The synthesized conjugated rotors are highly fluorescent (Φf = 0.39 to Φf = 0.10), and changes in their emission were observed upon variations of the surrounding media. Particularly, we found that they are sensitive to aggregation (THF/water) or high viscosity (methanol/glycerol) conditions. This work paves the way to develop new emissive rotors with exciting photophysical properties.

A multicomponent diversity-oriented synthesis of new highly emissive tetracyclic isoquinolines that target specific organelles is described. The title compounds were prepared via a three-step protocol starting with an Ugi four-component reaction, followed by either an intramolecular alkyne hydroarylation and subsequent alkene isomerization or through a Pomeranz-Fritsch-type cyclization with a final intramolecular Heck reaction. Subcellular localization studies of these compounds using green channel confocal microscopy revealed remarkable and distinctive distribution patterns in live cells, showing an unprecedented high selectivity and imaging contrast. The differentiated organelle visualization-including localizers for mitochondria, lysosomes, Golgi apparatus, endoplasmic reticulum, and plasma membrane-was achieved by varying the nature of the tetracyclic system and substituent pattern, changing the original four-component set in the starting Ugi reaction.

A synthetic approach to the 6-methyl-3,4-dihydropyrazinone core from Ugi adducts is described. This methodology relies on the regioselective C-N bond formation between an allenamide moiety at C-β and an amide anion formed under base-mediated conditions. This protocol allows easy access to tricyclic systems such as pyrazino[2,1-a]isoindole and pyrazino[2,1-a]isoquinoline nuclei.