Andrea Carletta
Université de Namur
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Featured researches published by Andrea Carletta.
Chemistry: A European Journal | 2017
Andrea Carletta; Floriana Spinelli; Simone d'Agostino; Barbara Ventura; Michele R. Chierotti; Roberto Gobetto; Johan Wouters; Fabrizia Grepioni
N-Salicilideneanilines are among the most studied thermo- and photochromic systems in the solid state. Although thermochromism is a general property of crystalline N-salicilideneanilines, photochromism is known in a limited number of cases. As a method for the construction of thermo- and photo-responsive molecular architectures, the co-crystallisation of 1,2,4,5-tetrafluoro-3,6-diiodobenzene (I2F4) with three selected imines of o-vanillin, named 1, 2 and 3, obtained through a condensation reaction with 3-aminopyridine, 4-bromoaniline and 4-iodoaniline, respectively, is reported herein. All crystals and co-crystals have been characterised by means of solid-state complementary techniques (X-ray diffraction, solid-state NMR spectroscopy, absorption and emission spectroscopy). The role of halogen bonding and crystal packing in the optical and chromic properties of all solid materials is discussed. All solids exhibit thermochromic behaviour, and three of them (2, 22 ⋅I2F4 and 32 ⋅I2F4) are also photochromic. Imine derivative 3 crystallises in two different polymorphic forms (3 A and 3 B) and a solvate (3Solv ). The bromo and iodo derivatives, 2 and 3 B, are isomorphous and form isomorphous co-crystals with I2F4, but behave differently when exposed to UV light because only crystalline 2 is photochromic. Interestingly, the replacement of bromine with iodine seems to turn off the photochromism because crystalline 3 A and 3Solv , and even the 20.7 30.3 solid solution, do not manifest photochromic behaviour.
CrystEngComm | 2015
Andrea Carletta; Jean Dubois; Anaëlle Tilborg; Johan Wouters
Substituted N-salicylidene aniline has been quantitatively prepared by mechanochemical synthesis starting from the corresponding aniline and ortho-vanillin. X-ray diffraction reveals that the compound crystallizes into two different polymorphic forms, due to its conformational flexibility. Ab initio conformational calculations combined with a CSD survey allow proper definition of the conformational space and selection of specific starting geometries for crystal structure prediction studies. Therefore, theoretical packing simulation was able to retrieve the two polymorphic structures in agreement with the experimental data. DSC calorimetric analysis provides extra information on the thermodynamic relationship between polymorphs I and II, and their exposure to liquid nitrogen, coupled with low-temperature X-ray analysis, highlights the structural reasons for the intrinsic thermochromic behaviour of the compound.
Acta Crystallographica Section B Structural Crystallography and Crystal Chemistry | 2015
Andrea Carletta; Anaëlle Tilborg; Laurence Moineaux; Jérôme de Ruyck; Livia Basile; Loredana Salerno; Giuseppe Romeo; Johan Wouters; Salvatore Guccione
Heme oxygenase-1 (HO-1) inhibition is associated with antitumor activity. Imidazole-based analogues show effective and selective inhibitory potency of HO-1. In this work, five single-crystal structures of four imidazole-based compounds are presented, with an in-depth structural analysis. In order to study the influence of the conformation of the ligands on binding to protein, conformational data from crystallography are compared with quantum mechanics analysis and molecular docking studies. Molecular docking of imidazole-based analogues in the active site of HO-1 is in good agreement with the experimental structures. Inhibitors interact with the heme cofactor and a hydrophobic pocket (Met34, Phe37, Val50, Leu147 and Phe214) in the HO-1 binding site. An alternate binding mode can be hypothesized for some inhibitors in the series.
ChemistryOpen | 2018
Melwin Colaço; Andrea Carletta; Mégane Van Gysel; Koen Robeyns; Nikolay Tumanov; Johan Wouters
Abstract Direct access to the protonated merocyanine forms of two substituted spiropyrans by mechanosynthesis or sonochemistry was explored. The compounds were formed by the condensation reaction of the methyleneindolium iodide salt with salicylaldehyde derivatives. X‐ray crystallography, 1H NMR spectroscopy, ab initio geometry optimization, and absorption spectroscopy were combined to provide a better understanding of the four‐state molecular switch system in which the newly synthesized protonated merocyanines were found to play a central role. The results of this study suggest that the stability of the protonated merocyanines requires acidic conditions, as treatment with base led to the corresponding unprotonated merocyanines, which in turn spontaneously converted into photochromic closed spiropyrans.
Acta Crystallographica Section B Structural Crystallography and Crystal Chemistry | 2015
Anaëlle Tilborg; Andrea Carletta; Johan Wouters
We present here a new structure of a 1:1 salt of trimethoprim with hemifumarate, highlighted by single-crystal X-ray diffraction and computational conformational studies. This salt was formed during cocrystallization assays conducted to combine trimethoprim and other APIs whose combination exhibits interesting properties. Theoretical in vacuo investigations have been performed on the organic salt through a DFT two-dimensional conformational scan of torsion angles between the two aromatic moieties of trimethoprim. The evaluation of relative energies for hydrogen-bond interactions in the structure has also been performed. Comparison with conformational data from structures implying trimethoprim retrieved from the Cambridge Structural Database (CSD) shows good agreement with theoretical results, proving the validity of vacuum ab initio calculations in describing the energetic landscape of the molecule and thereby gain initial insight into the prediction process for possible new conformations and therefore potential new polymorphs.
Crystal Growth & Design | 2015
Andrea Carletta; Céline Meinguet; Johan Wouters; Anaëlle Tilborg
Journal of Physical Chemistry C | 2016
Andrea Carletta; Xavier Buol; Tom Leyssens; Benoît Champagne; Johan Wouters
Journal of Physical Chemistry C | 2017
Jean Quertinmont; Andrea Carletta; Nikolay Tumanov; Tom Leyssens; Johan Wouters; Benoît Champagne
Journal of Physical Chemistry C | 2018
Andrea Carletta; Melwin Colaço; Sébastien R. Mouchet; Aurélie Plas; Nikolay Tumanov; Luca Fusaro; Benoît Champagne; Steve Lanners; Johan Wouters
Crystal Growth & Design | 2018
Andrea Carletta; Marija Zbačnik; Mégane Van Gysel; Matea Vitković; Nikolay Tumanov; Vladimir Stilinović; Johan Wouters; Dominik Cinčić