A series of double dihydromethylpiperazinediium metallic sulfates 1–7 [H₂mpz]M^II(SO₄)₂·nH₂O (mpz = 2-methylpiperazine, C₅H₁₂N₂) are prepared by slow evaporation using a racemic (R/S)-mpz (for 1, 2) or enantiopure R-mpz (for 3), S-mpz (for 4–7) and sulfates of Cu^II (for 5), Fe^II (for 1, 4), Co^II (for 7) and Zn^II (for 2, 3, 6), and characterized by infrared spectroscopy, elemental analysis and single crystal X-ray diffraction. The [M^II(H₂O)₆]²⁺, [(R/S)-H₂mpz]²⁺, [(R)-H₂mpz]²⁺ or [(S)-H₂mpz]²⁺ cations and 2SO₄ ²⁻ anions are linked together via two types of hydrogen bonds, Ow–Hw⋯O and N–H⋯O, leading to supramolecular arrangements. The use of the racemic 2-mpz provides alternatives in crystallization: a centrosymmetric structure where the enantiomers are related by an appropriate crystallographic symmetry operation or one where the enantiomers occupy the same crystallographic position, generating disorder. Compounds 1–7 act as diastereoselective catalysts for the nitroaldol (Henry) reaction. The diastereoselectivity can be regulated from exclusive threo to exclusive erythro isomer preparation with typical yields of 50–99%, depending on the catalyst and the substrate used.

Hybrid organic–inorganic perovskites (HOIPs) have attracted considerable attention for their scientific and technological potential in photovoltaics and optoelectronic devices. Recently, two-dimensional (2D) HOIPs have become established as useful active layers for photovoltaic applications, offering adjustable electronic levels, high charge carrier mobilities, and simplicity of thin-film device fabrication. In this work, we describe the preparation of a new Cu-based 2D hybrid perovskite, with the structural formula (C₆H₁₀N₂)[CuCl₄], of which crystallographic, spectroscopic, optical and magnetic properties have been studied and analyzed. The compound exhibits dominant ferromagnetic interactions. Fits of the χ(T) data to the 2D-ferromagnetic layer model yielded C = 0.456(2) emu-K mol-Oe⁻¹ and J = 5.5(1). Analysis of electromagnetic absorption and reflectance properties through the visible and near-infrared indicate an optical band gap of 1.24 eV (absorption) or 1.23 eV (reflection) and a direct, spin-forbidden electronic transition giving rise to a strong absorption band centered at 740 nm, which allows it to absorb a large portion of the solar spectrum. Although the absorption coefficient is lower than lead halide perovskites, it is greater than 1000 cm⁻¹ throughout the visible spectrum up to 1000 nm, giving the material potential as a solar absorber if relatively thick (∼5 μm) films are used. The nature of the electronic transition and frontier electronic states were studied by DFT and reveal valence and conduction bands arising from repeating CuCl₄ square planar structural units composed of hybridized Cl 3p_x,y orbitals and Cu 3d_x²−y² orbitals. The electronic structure and optical properties indicate that the material might be able to serve as a non-toxic alternative to lead-based HOIPs in some applications.

Fighting against the emergent coronavirus disease (COVID-19) remains a big challenge at the front of the world communities. Recent research has outlined the potential of various medicinal herbs to counteract the infection. This study aimed to evaluate the interaction of artemisinin, a sesquiterpene lactone extracted from the Artemisia genus, and its derivatives with the SARS-CoV-2 main protease. To assess their potential use against COVID-19, the interactions of the main active principle of Artemisia with the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) main protease (Mpro) was investigated through in silico probing. Our results showed that artemesinin and its derivatives manifested good oral absorption and bioavailability scores (0.55). They potently bound to the Mpro site of action—specifically, to its Cys145 residue. The selected compounds established two to three conventional hydrogen bonds with binding affinities ranging between −5.2 and −8.1 kcal/mol. Furthermore, artemisinin interactions with angiotensin converting enzyme 2 (ACE2) were dependent on the ACE2 allelic variants. The best score was recorded with rs961360700. A molecular dynamic simulation showed sufficient stability of the artemisinin–Mpro complex on the trajectory of 100 ns simulation frame. These binding interactions, together with drug-likeness and pharmacokinetic findings, confirmed that artemisinin might inhibit Mpro activity and explain the ethnopharmacological use of the herb and its possible antiviral activity against SARS-CoV-2 infection inducing COVID-19. Nevertheless, it interacted differently with the various ACE2 allelic variants reported to bind with the SARS-CoV-2 spike protein.

We report a novel synthetic procedure for the high-yield synthesis of metal–organic frameworks (MOFs) with fcu topology with a UiO-66-like structure starting from a range of commercial Zr^IV precursors and various substituted dicarboxylic linkers. The syntheses are carried out by grinding in a ball mill the starting reagents, namely, Zr salts and the dicarboxylic linkers, in the presence of a small amount of acetic acid and water (1 mL total volume for 1 mmol of each reagent), followed by incubation at either room temperature or 120 °C. Such a simple “shake ‘n bake” procedure, inspired by the solid-state reaction of inorganic materials, such as oxides, avoids the use of large amounts of solvents generally used for the syntheses of Zr-MOF. Acidity of the linkers and the amount of water are found to be crucial factors in affording materials of quality comparable to that of products obtained under solvo- or hydrothermal conditions.