研究领域

General and Inorganic Chemistry

Design, synthesis, investigation and applications of molecular crystalline materials: (1) Synthesis and properties of new crystal forms (polymorphs, solvates, molecular and ionic co-crystals, coordination compounds with bio-compatible metals) of organic molecules of pharmaceutical and agrochemical interest; (2) Supramolecular gels with d-block metals; (3) Luminescent MOFs of copper(I) and thin-films for OLED applications; (4) tuning of luminescence of molecular solids via functionalization or co-crystallization; (5) crystal engineering of molecular organic semiconductors for applications as sensors; (6) Structural determination from powder data. Techniques: solvent-free synthesis, X-ray diffraction, DSC, TGA, hot stage microscopy.

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Luminescence Properties of 1,8-Naphthalimide Derivatives in Solution, in Their Crystals, and in Co-crystals: Toward Room-Temperature Phosphorescence from Organic Materials Barbara Ventura,* Alessio Bertocco, Dario Braga, Luca Catalano, Simone d’Agostino,Fabrizia Grepioni *, and Paola Taddei *, J. Phys. Chem. C, 2014, 118 (32), pp 18646–18658, DOI: 10.1021/jp5049309 ABSTRACT: Crystalline 1,8-naphthalimide derivatives bearing a bromine atom at the 4-position and a 2-, 3-, or 4- methylpyridine at the imidic N-position have been synthesized, and their co-crystals with the coformer 1,4-diiodotetrafluorobenzene have been obtained via mechanochemistry. The structure of crystals and co-crystals has been characterized by means of X-ray diffraction and Raman and IR analysis. The luminescence properties of the derivatives have been explored both in solution and in their solid crystals and co-crystals. All of the compounds exhibit weak fluorescence in air-equilibrated solutions at room temperature and both fluorescence and phosphorescence at low temperature. In air-free solvent, all of the derivatives show phosphorescence at room temperature, at variance with the unsubstituted 1,8-naphthalimide model. Solid crystals display a red-shifted fluorescence with an increased emission quantum yield as compared to solution, whereas co-crystals show different behaviors. For all of the solid compounds, phosphorescence could be observed at room temperature by means of a gated detection. The dependence of the luminescence features of the solid materials on the intermolecular interactions that occur in the lattice is discussed. Italian Patent on "Co-crystals with high fluorescence yield based on 1,8-naphthalimide derivatives and halogenated co-formers"): Domanda di brevetto italiano N.RM2014A000327 depositata il 20.06.2014 dal titolo "CO-CRISTALLI CON ELEVATA RESA DI FLUORESCENZA BASATI SU DERIVATI DEL 1,8-NAFTALIMIDE E CO-FORMANTI ALOGENATI" ALMA MATER STUDIORUM – UNIVERSITA’ DI BOLOGNA e CONSIGLIO NAZIONALE DELLE RICERCHE Inventori: BRAGA DARIO, GREPIONI FABRIZIA, D'AGOSTINO SIMONE, CATALANO LUCA, BERTOCCO ALESSIO, VENTURA BARBARA Ionic co-crystals of racetams: solid-state properties enhancement of neutral active pharmaceutical ingredients via addition of Mg2+ and Ca2+ chlorides Fabrizia Grepioni,* Johan Wouters,* Dario Braga, Saverio Nanna, Baptiste Fours, Gérard Coquerel, Geraldine Longfils, Sandrine Rome, Luc Aerts and Luc Quéré*, CrystEngComm, 2014, 16, 5887-5896, DOI: 10.1039/C4CE00409D ABSTRACT: Mechanochemical and solution based reactions of solid brivaracetam (BRV) and seletracetam (SEL), antiepileptic drugs from UCB's pipeline, with the inorganic salts MgCl2 and CaCl2, yield ionic co-crystals with changed or improved physico-chemical properties with respect to pure drugs (melting point, hygroscopicity, crystal morphology). All co-crystals are characterized via a combination of solid-state techniques, i.e. single crystal and powder X-ray diffraction, variable temperature X-ray diffraction, DSC, TGA and hot-stage microscopy (HSM). Intriguing Case of Pseudo-Isomorphism between Chiral and Racemic Crystals of rac- and (S)/(R)2-(1,8-Naphthalimido)-2-quinuclidin-3-yl, and Their Reactivity Toward I2 and IBr Simone d’Agostino, Dario Braga, Fabrizia Grepioni,* and Paola Taddei,* Crystal Growth & Design, 2014, 14 (2), pp 821–829, DOI: 10.1021/cg401686p ABSTRACT: Condensation reactions between 1,8-naphthalic anhydride and racemic 3-aminoquinuclidine or chiral (S) or (R)-(−)-3-aminoquinuclidine allowed preparation of three novel racemic and enantiopure aza-donor ligands, namely NMiABCO (1), (S)NMiABCO (2a), and (R)NMiABCO (2b). Racemic NMiABCO (1) crystallizes in the monoclinic space group P21/c, Z′ = 1, while enantiopure (S)NMiABCO (2a) and (R)NMiABCO (2b) crystallize in the chiral monoclinic space group P21, Z′ = 2, and show significant pseudocentrosymmetry, being pseudo-isomorphous with racemic NMiABCO (1). Reactivity of both racemic and enantiopure NMiABCO toward iodine and interhalogen IBr was also investigated as a way to remove the pseudoisomorphism, yielding the three new molecular adducts [NMiABCO·I2] (3), [(S)NMiABCO·I2]·xCHCl3 (4), [(S)NMiABCO·IBr]·xCHCl3 (5) and the molecular salt [HNMiABCO][IBr2] (6). Synthesis of complexes 3 and 4 was also carried out in the solid state via kneading and vapor digestion techniques. All compounds were fully characterized via single crystal and powder X-ray diffraction and Raman spectroscopy. Imazamox: A Quest for Polymorphic Modifications of a Chiral and Racemic Herbicide Dario Braga, Laura Chelazzi, Fabrizia Grepioni,* Saverio Nanna, Katia Rubini, Marco Curzi, Stefano Giaffreda, Heidi E. Saxell, Matthias Bratz, and Tiziana Chiodo*, dx.doi.org/10.1021/cg4019025 | Cryst. Growth Des. 2014 The structure−property relationships of new polymorphs of the chiral herbicide imazamox were investigated by X-ray diffraction, hot stage microscopy (HSM), and differential scanning calorimetry (DSC). Four different polymorphs of imazamox(R) were found. The relationship between different crystal forms, relative thermal stability, and possible conversions pathways was explored. Racemic imazamox, for which no polymorphic modifications could be observed, was also characterized in the solid state. Pub. No.:WO/2014/006576 International Application No.:PCT/IB2013/055448 Publication Date:09.01.2014 International Filing Date:03.07.2013 IPC:C07D 498/22 (2006.01), A61K 31/437 (2006.01), A61K 47/18 (2006.01), A61K 9/00(2006.01), A61P 31/00 (2006.01) Applicants: ALFA WASSERMANN S.P.A. [IT/IT]; 1, Via Enrico Fermi I-65020 Alanno (Pescara) (IT) Inventors: VISCOMI, Giuseppe Claudio; (IT). CHELAZZI, Laura; (IT). GREPIONI, Fabrizia; (IT). BRAGA, Dario; (IT). KINDT, Maddalena; (IT) Priority Data: BO2012A000368 06.07.2012 IT Title (EN) PHARMACEUTICAL COMPOSITIONS COMPRISING RIFAXIMIN AND AMINO ACIDS, PREPARATION METHOD AND USE THEREOF Abstract: (EN)The object of the present invention concerns rifaximin compositions comprising amino acids, characterized in that they increase rifaximin solubility in aqueous solutions. Rifaximin compositions comprising amino acids are useful in the treatment of disease wherein amino acids and rifaximin are efficacious. The present invention relates to pharmaceutical compositions comprising rifaximin or one of the pharmaceutically acceptable salts thereof and one or more amino acid(s), wherein the molar ratio between the amino acid(s) and rifaximin is comprised between 1:1 and 10:1, preferably between 1:1 and 5:1, together with pharmaceutically acceptable excipients. Moreover, the present invention relates to rifaximin crystals characterized in that they are obtained by means of a process comprising: a) dissolution of the compositions of rifaximin and amino acids, wherein amino acids and rifaximin are in a molar ratio comprised between 1:1 and 10:1 according to Claim 1, in solutions formed by ethanol/water, in a volumetric ratio comprised between 1:1 and 1:10 (v/v); b) evaporation of the solution obtained in step a) at temperatures comprised between room temperature and 40°C, in a time period comprised between 1 and 10 days; wherein the resulting crystals have monoclinic space group P21 and cell parameters comprised in the ranges: a: 13.7(1)-13.8(1) Å; b: 19.7(1)-19.9 (1) Å; c: 16.4(6)-16.6(6) Å;β: 92.1 (1)-91.9(1) deg.