In this study, three novel magnetic nanocomposites based on carboxyl-functionalized SBA-15 silica and magnetite nanoparticles were prepared through an effective and simple procedure and applied for methylene blue (MB) and malachite green G (MG) adsorption from single and binary solutions. Structure, composition, morphology, magnetic, and textural properties of the composites were thoroughly investigated. The influence of the amount of carboxyl functional groups on the physicochemical and adsorptive properties of the final materials was investigated. The capacity of the synthesized composites to adsorb MB and MG from single and binary solutions and the factors affecting the adsorption process, such as contact time, solution pH, and dye concentration, were assessed. Kinetic modelling showed that the dye adsorption mechanism followed the pseudo-second-order kinetic model, indicating that adsorption was a chemically controlled multilayer process. The adsorption rate was simultaneously controlled by external film diffusion and intraparticle diffusion. It was evidenced that the molecular geometry of the dye molecule plays a major role in the adsorption process, with the planar geometry of the MB molecule favoring adsorption. The analysis of equilibrium data revealed the best description of MB adsorption behavior by the Langmuir isotherm model, whereas the Freundlich model described better the MG adsorption.

Three 2,1,3-benzothiadiazole-based ligands decorated with two pyridyl groups, 4,7-di(2-pyridyl)-2,1,3-benzothiadiazol (2-PyBTD), 4,7-di(3-pyridyl)-2,1,3-benzothiadiazol (3-PyBTD) and 4,7-di(4-pyridyl)-2,1,3 benzothiadiazol (4-PyBTD), generate Zn^II and Ag^I complexes with a rich structural variety: [Zn(hfac)₂(2-PyBTD)] 1, [Zn₂(hfac)₄(2-PyBTD)] 2, [Ag(CF₃SO₃)(2-PyBTD)]₂3, [Ag(2-PyBTD)]₂(SbF₆)₂4, [Ag₂(NO₃)₂(2-PyBTD)(CH₃CN)] 5, [Zn(hfac)₂(3-PyBTD)] 6, [Zn(hfac)₂(4-PyBTD)] 7, [ZnCl₂(4-PyBTD)₂] 8 and [ZnCl₂(4-PyBTD)] 9 (hfac = hexafluoroacetylacetonato). The nature of the resulting complexes (discrete species or coordination polymers) is influenced by the relative position of the pyridyl nitrogen atoms, the nature of the starting metal precursors, as well as by the synthetic conditions. Compounds 1 and 8 are mononuclear and 2, 3 and 4 are binuclear species. Compounds 6, 7 and 9 are 1D coordination polymers, while compound 5 is a 2D coordination polymer, the metal ions being bridged by 2-PyBTD and nitrato ligands. The solid-state architectures are sustained by intermolecular π–π stacking interactions established between the pyridyl group and the benzene ring from the benzothiadiazol moiety. Compounds 1, 2, 7–9 show luminescence in the visible range. Density Functional Theory (DFT) and Time Dependent Density Functional Theory (TD-DFT) calculations have been performed on the Zn^II complexes 1 and 2 in order to disclose the nature of the electronic transitions and to have an insight on the modulation of the photophysical properties upon complexation.

A new series of nanostructured materials was obtained by functionalization of SBA-15 mesoporous silica with Ru(II) and Ru(III) complexes bearing Schiff base ligands derived from salicylaldehyde and various amines (1,2-diaminocyclohexane, 1,2-phenylenediamine, ethylenediamine, 1,3-diamino-2-propanol, N,N-dimethylethylenediamine, 2-aminomethyl-pyridine, and 2-(2-aminoethyl)-pyridine). The incorporation of ruthenium complexes into the porous structure of SBA-15 and the structural, morphological, and textural features of the resulting nanostructured materials were investigated by FTIR, XPS, TG/DTA, zeta potential, SEM, and N₂ physisorption. The ruthenium complex-loaded SBA-15 silica samples were tested against A549 lung tumor cells and MRC-5 normal lung fibroblasts. A dose-dependent effect was observed, with the highest antitumoral efficiency being recorded for the material containing [Ru(Salen)(PPh₃)Cl] (50%/90% decrease in the A549 cells’ viability at a concentration of 70 μg/mL/200 μg/mL after 24 h incubation). The other hybrid materials have also shown good cytotoxicity against cancer cells, depending on the ligand included in the ruthenium complex. The antibacterial assay revealed an inhibitory effect for all samples, the most active being those containing [Ru(Salen)(PPh₃)Cl], [Ru(Saldiam)(PPh₃)Cl], and [Ru(Salaepy)(PPh₃)Cl], especially against Staphylococcus aureus and Enterococcus faecalis Gram-positive strains. In conclusion, these nanostructured hybrid materials could represent valuable tools for the development of multi-pharmacologically active compounds with antiproliferative, antibacterial, and antibiofilm activity.

The reactions of copper(II) salts with aminoalcohols frequently afford alkoxido-bridged dimers. Neutral (e.g. bis(4-pyridyl) derivatives) or anionic divergent ligands (e.g. polycarboxylate anions, polycyanido-metallates) are employed as spacers. In this paper, a rich variety of structures are reviewed, emphasizing the role played by the denticity of the aminoalcohols and of the linkers, as well as by the accompanying anions, in the network topology. The involvement of coordinative and non-covalent bonds (π–π stacking, argentophilic/aurophilic, π⋯Hg interactions, hydrogen bonds) in sustaining the solid-state architectures is also discussed.

Two new 2p–3d complexes, (Et₃NH)[ML(hfac)₂], have been obtained using the nitronyl-nitroxide radical (HL) derived from 2-hydroxy-3-methoxy-5-nitrobenzaldehyde (M = Mn 1; Co 2). The two compounds are isomorphous and their structures consist of anionic mononuclear species, [M(hfac)₂L]⁻, M = Mn 1; Co 2, and triethylammonium cations, Et₃NH⁺. The metal ions adopt an octahedral geometry, being coordinated by phenoxido and aminoxyl oxygen atoms from the ligand and four oxygen atoms from the hexafluoroacetylacetonato (hfac⁻) ligand. The cryomagnetic behaviors of the two compounds reveal relatively strong antiferromagnetic M(II)-Rad interactions (J_MnRad = −191 cm⁻¹, J_CoRad = −166 cm⁻¹ with H = −JS_MS_Rad). The EPR spectra (X- and Q-band) of compound 1 below 70 K show the characteristical features of a S = 2 spin system with zero field splitting terms of D = 0.26 cm⁻¹ and E = 0.031 cm⁻¹.