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A highly complex crystal structure of stoichiometric Mg5(en)6(BH4)10 was solved from single crystal synchrotron X-ray diffraction and confirmed by neutron powder diffraction (NPD) on isotopically substituted Mg(en)1.2(11BD4)2. We highlight the role of the amorphous Mg(BH4)2 in the reactivity of the Mg(BH4)2-en system and characterized a previously overlooked phase, Mg(en)2(BH4)2.

Aliphatic hydroxamic acids (HA) with varying numbers of carbon atoms, C2, C6, C8, C10, C12 and C17, and corresponding Fe(II), Fe(III), Ni(II), Cu(II) and Zn(II) complexes have been synthesized and characterized by various methods, including structural determination by single crystal X-ray diffraction and theoretical calculations. The biological activities of HA and their complexes have been assessed on a panel of pathogens, including eight bacteria strains and one fungus. The C12 aliphatic HA displayed the lowest minimum inhibitory concentrations (MIC) towards several microbial strains and a selective antifungal activity. This antifungal selectivity was further improved considering the Ni(II), Cu(II) and Zn(II) complexes of C12 HA showed higher IC50 values, thus less impact on the SiHa human cell line viability. This work warrants further investigation to understand the underlying mechanism of action and potential biological applications of HA and the derived metal complexes.

info:eu-repo/semantics/published

Aliphatic hydroxamic acids (HA) with varying numbers of carbon atoms, C2, C6, C8, C10, C12 and C17, and corresponding Fe(II), Fe(III), Ni(II), Cu(II) and Zn(II) complexes have been synthesized and characterized by various methods, including structural determination by single crystal X-ray diffraction and theoretical calculations. The biological activities of HA and their complexes have been assessed on a panel of pathogens, including eight bacteria strains and one fungus. The C12 aliphatic HA displayed the lowest minimum inhibitory concentrations (MIC) towards several microbial strains and a selective antifungal activity. This antifungal selectivity was further improved considering the Ni(II), Cu(II) and Zn(II) complexes of C12 HA showed higher IC50 values, thus less impact on the SiHa human cell line viability. This work warrants further investigation to understand the underlying mechanism of action and potential biological applications of HA and the derived metal complexes., SCOPUS: ar.j, info:eu-repo/semantics/published

N-Salicylideneaniline (also called anil) is a compound which exhibits photochromism (reversible color change induced by light) in the solid-state. Such a feature is quite rare and requires in-deep studies to fully understand it, especially because it can be quite useful in many industrial applications such as secured inks (for banknotes for instance), screens or even optical data storage. Within this thesis, N-Salicylideneaniline and many of its derivatives (the “anils”) were studied in the scope of crystal engineering in order to establish a structure-property relationship and to improve its properties. More specifically, cocrystals were researched and studied using small organic molecules (such as carboxylic acids, amides, amines, benzene halides) as coformers. This resulted in the identification of about 100 cocrystals through the use of X-ray powder diffraction (XRPD), single crystal X-ray diffraction (SC-XRD), diffuse reflectance spectroscopy (DRS), thermal analysis such as thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) along with a few other methods such as Raman spectroscopy. The amount of collected data allowed to show a correlation between the number of intermolecular interactions involving the “moving moiety” of the anils and the presence of photochromism. We also present here a new approach of the Diffuse Reflectance Spectroscopy data treatment, which allows a better classification of the photochromic properties and also allowed the discovery of “weakly” photochromic compounds. These results encourage a revision of the old-empirical “dihedral angle rule” especially because a link between the intensity of photochromism and the torsion angle has been observed in this work. In the last part, we focused on cocrystals containing 2 different anils (instead of one anil and one coformer) and this allowed to observe the existence of a complex multi-phases binary diagram in the case of N-Salicylideneaniline/ N-Salicylidene-4-fluoroanil, (SC - Sciences) -- UCL, 2022

Sodium and iron make up the perfect combination for the growing demand for sustainable energy storage systems, given the natural abundance and sustainability of the two building block elements. However, most sodium–iron electrode chemistries are plagued by intrinsic low energy densities with continuous ongoing efforts to solve this. Herein, the chemical space of a series of (meta)stable, off-stoichiometric Fe-PO4-F phases is analyzed. Some are found to display markedly improved electrochemical activity for sodium storage, as compared to the amorphous or thermodynamically stable phases of equivalent composition. The metastable crystalline Na1.2Fe1.2PO4F0.6 delivers a reversible capacity of more than 140 mAh g−1 with an average discharge potential of 2.9 V (vs Na+/Na0) resulting in a practical specific energy density of 400 Wh kg−1 (estimated at the material level), outperforming many developed Fe-PO4 analogs thus far, with further multiple possibilities to be explored toward improved energy storage metrics. Overall, this study unlocks the possibilities of off-stoichiometric Fe-PO4-F cathode materials and reveals the importance to explore the oft-overlooked metastable or transient state materials for energy storage.

While common in biological systems, building blocks with low symmetry and flexibility pose numerous problems for synthetic self-assembly such as the formation of isomers of assemblies that are usually difficult to distinguish and purify. We herein report a design and synthesis strategy relying on shape complementarity and conformational constraints in dual curvature ligands that effectively promotes high selectivity during self-assembly and self-sorting of metal-organic assemblies. Three aromatic amide-based ligands (L1-L3) with a central 1,8-diazatriptycene core were designed and used for self-assembly with Pd2+. While hundreds of stereoisomers based on the conformational flexibility around the amides and the unsymmetrical non-planar structure of the core are possible upon coordination with the metal, the constraints designed into the ligands direct the self-assembly towards only a single Pd2L4 cage (L1) or Pd4L8 double-walled metallomacrocycle (L2) structure, even in mixtures of the ligands. We further demonstrate that this structural approach and the modularity of the ligand synthesis affords ready access to the first deep endohedral functionalized double-walled Pd4L8 cavitands (L3). These results highlight the potential of this new design strategy and open the door to selectively functionalized cavity-based architectures for numerous applications.

The design and construction of colorimetric ammonia (NH3) sensors with high selectivity, great stability and short response times at room temperature are highly needed for human health and food safety. We report herein a chiral supramolecular FeII 4L4 metal-organic cage (MOC-1) able to detect NH3(g) at room temperature in less than 10 s, which we used to monitor food safety at 4 1C on fresh bacon bits. The detection is accompanied by a dramatic colour change from light brown to purple. In addition, MOC-1 exhibits superior selectivity among NH3(g) and twelve analytes including common solvents and amines. The reproducibility was studied by five continuous cyclic tests. Simple and low-cost smartphone-based and chemometrics analytical methods were used to study the sensing performance. The thermal stability is more than 200 1C. The sensing mechanism is associated with a high-spin to low-spin transition of the FeII ions, as expected for a ligand field strength that meets spin crossover conditions. These results show the high potential of MOC-1 as a convenient and inexpensive NH3 gas sensor at room temperature, which could be used in the field of food safety assessment.