Daoud Naoufal

A new, simple, efficient and selective preparation of apical mono-phosphino closo-decahydrido-decaborate [N(n-Bu)₄]₂[1-B₁₀H₉PR₃] is reported starting from [N(n-Bu)₄]₂[1-B₁₀H₉I], tertiary phosphines and Pd(0)-PR₃ under mild conditions.

Quantum chemistry calculations and solution-state IR spectroscopy are combined to probe the relationship between constituent amino acid configurations and helix topologies in hybrid α/γ-peptides.

A green, fast and selective approach for the synthesis of mono-substituted closo-decaborate derivatives [2-B₁₀H₉COR]²⁻ has been established via a nucleophilic addition reaction between the carbonyl derivative of closo-decaborate [2-B₁₀H₉CO]⁻ and the corresponding Grignard reagent RMgX, where R is the ethyl, iso-propyl, pentyl, allyl, vinyl and propynyl groups. This approach is accomplished under mild conditions with 70–80% yields. The significance of these derivative is their ability to constitute building blocks for polymeric integration via the allyl, vinyl and propynyl substituents. All products were characterized by ¹¹B, ¹H and ¹³C NMR, elemental analysis and mass spectrometry.

A green, fast and selective approach for the synthesis of mono-substituted closo-decaborate derivatives [2-B10H9COR]n– has been established via a nucleophilic addition reaction between the carbonyl derivative of closo-decaborate [2-B10H9CO]– and the corresponding Grignard reagent RMgX, where R is the ethyl, iso-propyl, pentyl, allyl, vinyl, and propynyl groups. This approach is accomplished under mild conditions with 70–80% yields. The significance of these derivative is their ability to constitute building blocks for polymeric integration via the allyl, vinyl and propynyl substituents. All products were characterized by 11B, 1H, and 13C NMR, elemental analysis and mass spectrometry.

The increase in environmental pollution, especially water pollution, has intensified the requirement for new strategies for the treatment of water sources. Furthermore, the improved properties of nano-ferrites permit their usage in wastewater treatment. In this regard, novel Mg_0.33Ni_0.33Co_0.33La_xFe_2−xO₄ nanoparticles (NPs), where 0.00≤x≤0.08, were synthesized to test their photocatalytic, antibacterial and antibiofilm activities. The structural and optical properties of the prepared NPs were investigated by X-ray powder diffraction (XRD), transmission electron microscopy (TEM), UV-Vis spectroscopy and photoluminescence (PL) analysis. As La content increases, the bandgap energy increases, whereas the particle size decreases. The photocatalytic activity of the prepared NPs is evaluated by the degradation of methylene blue (MB) dye under sunlight irradiation. Superior activity is exhibited by Mg_0.33Ni_0.33Co_0.33La_0.01Fe_1.99O₄ NPs. The influence of catalyst dosage, pH, temperature and addition of graphene (Gr) on the photodegradation reaction was studied. Increasing the pH and temperature improved the rate of the photodegradation reaction. The antibacterial and antibiofilm activities of the NPs were assessed against Escherichia coli, Leclercia adecarboxylata, Staphylococcus aureus and Enterococcus faecium. Mg_0.33Ni_0.33Co_0.33Fe₂O₄ NPs inhibited bacterial growth. They had bacteriostatic activity on all isolates, with a greater effect on Gram-positive bacteria. All tested nano-ferrites had significant antibiofilm activities against some biofilms.

Herein we report the synthesis of a new class of compounds associating Keggin and Dawson-type Polyoxometalates (POMs) with a derivative of the anionic decahydro-closo-decaborate cluster [B₁₀H₁₀]²⁻ through aminopropylsilyl ligand (APTES) acting as both a linker and a spacer between the two negatively charged species. Three new adducts were isolated and fully characterized by various NMR techniques and MALDI-TOF mass spectrometry, notably revealing the isolation of an unprecedented monofunctionalized SiW₁₀ derivative stabilized through intramolecular H-H dihydrogen contacts. DFT as well as electrochemical studies allowed studying the electronic effect of grafting the decaborate cluster on the POM moiety and its consequences on the hydrogen evolution reaction (HER) properties.

This paper deals with the formation of host‐guest systems between cyclodextrins and the closo‐decahydrodecaborate cluster. The inclusion processes, although involving weak interaction, were evidenced in solution by ESI‐MS and various NMR techniques. ITC measurements provided thermodynamic parameters, and DFT calculations gave some elements that help in understanding these processes.

The magnetic properties of the pentacoordinate [M^II(Me₄cyclam)N₃]⁺ (Me₄cyclam=tetramethylcyclam; N₃=azido; M=Ni, Co) complexes were investigated. Magnetization and EPR studies indicate that they have an easy plane of magnetization with axial anisotropy parameters D close to 22 and greater than 30 cm⁻¹ for the Ni and Co complexes, respectively. Ab initio calculations reproduced the experimental values of the zero‐field splitting parameters and allowed the orientation of the anisotropy tensor axes with respect to the molecular frame to be determined. For M=Ni, the principal anisotropy axis lies along the Ni−N_azido direction perpendicular to the Ni(Me₄cyclam) mean plane, whereas for M=Co it lies in the Co(Me₄cyclam) mean plane and thus perpendicular to the Co−N_azido direction. These orientations match one of the possible solutions experimentally provided by single‐crystal cantilever torque magnetometry. To rationalize the geometry and its impact on the orientation of the anisotropy tensor axis, calculations were carried out on model complexes [Ni^II(NCH)₅]²⁺ and [Co^II(NCH)₅]²⁺ by varying the geometry between square pyramidal and trigonal bipyramidal. The geometry of the complexes was found to be the result of a compromise between the electronic configuration of the metal ion and the structure‐orienting effect of the Me₄cyclam macrocycle. Moreover, the orientation of the anisotropy axes is mainly dependent on the geometry of the complexes.

The reactions of the ammonium salt of closo -decahydrodecaborate (NH4 )2 B10 H10 with alcohols were studied in concentrated sulfuric acid medium. Alcohols ROH (R = CH3 , C2 H5 , C3 H7 , iso -C3 H7 , C4 H9 , 2-C4 H9 , ter -C4 H9, C5 H11 ) played the r