Mebendazole mesylate monohydrate: a new route to improve the solubility of mebendazole polymorphs

Mebendazole mesylate monohydrate, a new stable salt of mebendazole (MBZ), has been synthesized and fully characterized. It was obtained from recrystallization of MBZ forms A, B, or C in diverse solvents with the addition of methyl sulfonic acid solution. The crystal packing is first organized as a two-dimensional array consisting of rows of alternating MBZ molecules linked to columns of mesylate ions by hydrogen bonds. The three-dimensional structure is further developed by classical intermolecular interactions involving water molecules. In addition, nonclassical contacts are also found. The vibrational behavior is consistent with the crystal structure, the most important functional groups showing shifts to lower or higher frequencies in relation to the MBZ polymorphs. Thermal analysis indicates that the compound is stable up to 50°C. Decomposition occurs in five steps. Solubility studies show that the title compound presents a significant higher performance than polymorph C.CNPqCAPESFAPESPCONICET (PIP 2008-01360)SECyT-UNS

Intermolecular Contacts Influencing the Conformational and Geometric Features of the Pharmaceutically Preferred Mebendazole Polymorph C

Mebendazole (MBZ) is a common benzimidazole anthelmintic that exists in three different polymorphic forms, A, B, and C. Polymorph C is the pharmaceutically preferred form due to its adequated aqueous solubility. No single crystal structure determinations depicting the nature of the crystal packing and molecular conformation and geometry have been performed on this compound. The crystal structure of mebendazole form C is resolved for the first time. Mebendazole form C crystallizes in the triclinic centrosymmetric space group and this drug is practically planar, since the least-squares methyl benzimidazolylcarbamate plane is much fitted on the forming atoms. However, the benzoyl group is twisted by 31(1)degrees from the benzimidazole ring, likewise the torsional angle between the benzene and carbonyl moieties is 27(1)degrees. The formerly described bends and other interesting intramolecular geometry features were viewed as consequence of the intermolecular contacts occurring within mebendazole C structure. Among these features, a conjugation decreasing through the imine nitrogen atom of the benzimidazole core and a further resonance path crossing the carbamate one were described. At last, the X-ray powder diffractogram of a form C rich mebendazole mixture was overlaid to the calculated one with the mebendazole crystal structure. (C) 2008 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 98:2336-2344, 2009Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)CNPq (CNPQ)FAPESPFundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Fundação de Amparo à Pesquisa do Estado de Minas Gerais (FAPEMIG)FAPEMIGCONICET[PID 6246/05]Consejo Nacional de Investigaciones Científicas y Técnicas de Argentina (CONICET)UNSL (Argentina)UNSL (Argentina

Photoluminescence, unconventional-range temperature sensing, and efficient catalytic activities of lanthanide metal–organic frameworks

A luminescent lanthanide metal-organic framework (MOF) based on Eu3+ and Tb3+ ions with 2-phenylsuccinate (EuTb-psa) was obtained solvothermally to explore its behavior as a temperature sensor in an unconventional temperature range through the study of the thermal evolution of the hypersensitive 4f-4f D-5(0) -> F-7(2) transition and the luminescence life-time. The efficiency of the luminescence process was evaluated through the europium intrinsic quantum yield (Q(Eu)), and its variation as a function of temperature is also reported. The optical properties of four isostructural compounds (Pr-psa, Nd-psa, Gd-psa, and Tb-psa) were investigated and compared with those of related compounds. The energy of the triplet state of the ligand was also estimated. The samples were fully characterized by single-crystal and powder X-ray diffraction, thermal analysis, and vibrational spectroscopy. The heterogeneous catalytic activities of a series of Ln-psa MOFs (with Ln = Sm, Eu, Gd, Tb, EuGd, and EuTb) were evaluated in a one-pot cyanosilylation with benzaldehyde as the substrate

Two Sets of Metal Organic Frameworks along the Lanthanide Series Constructed by 2,3-Dimethylsuccinate: Structures, Topologies, and Strong Emission without Ligand Sensitization

Reactions in aqueous solution under hydrothermal conditions between (±)-2,3-dimethylsuccinic acid and lanthanide chlorides lead to two different isostructural types with chemical formulas [Ln₂­(C₆H₈­O₄)₃­(H₂O)₂] Ln­(III) = Pr–Eu (except Pm) (Type I, compounds <b>1</b>–<b>4</b>) and [Ln₂­(C₆H₈­O₄)₃] Ln­(III) = Tb–Yb (except Tm) (Type II, compounds <b>5</b>–<b>9</b>). The crystal structure has been solved for the Pr (<b>1</b>)-, Sm (<b>3</b>)-, and Ho (<b>7</b>)-containing compounds by means of single-crystal XRD methods, whereas powder XRD Rietveld refinement was used for the rest of the MOFs. Compounds <b>1</b>–<b>4</b> crystallize in the triclinic space group <i>P</i>1̅, whereas compounds <b>5</b>–<b>9</b> belong to the tetragonal space group <i>P</i>4₃2₁2. Type I and II compounds are 3D frameworks consisting of chains of [LnO₈­(H₂O)] or [LnO₈] polyhedra, respectively, linked by dimethylsuccinate anions, giving rise to I¹O² connectivity. All the compounds were characterized by X-ray diffraction, variable-temperature Fourier transform infrared spectroscopy, and thermal analysis. An exhaustive topological study was performed in comparison with other related compounds. The photoluminescent (PL) properties for compounds <b>3</b>, <b>4</b>, and <b>5</b> have been also explored, indicating that a metal-centered luminescent process takes place

Photoluminescence, unconventional-range temperature sensing, and efficient catalytic activities of lanthanide metal-organic frameworks

A luminescent lanthanide metal-organic framework (MOF) based on Eu and Tb ions with 2-phenylsuccinate (EuTb-psa) was obtained solvothermally to explore its behavior as a temperature sensor in an unconventional temperature range through the study of the thermal evolution of the hypersensitive 4f-4f D→F transition and the luminescence lifetime. The efficiency of the luminescence process was evaluated through the europium intrinsic quantum yield (Q), and its variation as a function of temperature is also reported. The optical properties of four isostructural compounds (Pr-psa, Nd-psa, Gd-psa, and Tb-psa) were investigated and compared with those of related compounds. The energy of the triplet state of the ligand was also estimated. The samples were fully characterized by single-crystal and powder X-ray diffraction, thermal analysis, and vibrational spectroscopy. The heterogeneous catalytic activities of a series of Ln-psa MOFs (with Ln = Sm, Eu, Gd, Tb, EuGd, and EuTb) were evaluated in a one-pot cyanosilylation with benzaldehyde as the substrate. A luminescent lanthanide metal-organic framework (MOF) based on Eu and Tb ions with 2-phenylsuccinate (EuTb-psa) is explored as a temperature sensor. The optical properties of four isostructural compounds (Pr-psa, Nd-psa, Gd-psa, and Tb-psa) are also investigated. The heterogeneous catalytic activities of these Ln-psa MOFs are evaluated in a one-pot cyanosilylation reaction.This work was supported by the Consejo Nacional de Investigaciones Científicas y Técnicas (PIP CONICET 112‐201101‐ 00912), ANPCyT PICT‐2012‐1994 and Universidad Nacional de San Luis (PROICO 2‐1612). G. E. G. acknowledges a CONICET PhD fellowship. R. V. D. and A. M. K. thank the Hercules Foundation (project AUGE/09/024 “Advanced Luminescence Setup”) for funding. A. M. and E. G. P. thank the Spanish Ministry of Economy and Competitiveness (MINECO) project MAT2013‐45460‐R, and Madrid S2013/MIT‐2740 (PHAMA_2.0). MINECO/ICTI2013-2016/MAT2013‐45460‐

Two Sets of Metal Organic Frameworks along the Lanthanide Series Constructed by 2,3-Dimethylsuccinate: Structures, Topologies, and Strong Emission without Ligand Sensitization

Reactions in aqueous solution under hydrothermal conditions between (±)-2,3-dimethylsuccinic acid and lanthanide chlorides lead to two different isostructural types with chemical formulas [Ln₂­(C₆H₈­O₄)₃­(H₂O)₂] Ln­(III) = Pr–Eu (except Pm) (Type I, compounds <b>1</b>–<b>4</b>) and [Ln₂­(C₆H₈­O₄)₃] Ln­(III) = Tb–Yb (except Tm) (Type II, compounds <b>5</b>–<b>9</b>). The crystal structure has been solved for the Pr (<b>1</b>)-, Sm (<b>3</b>)-, and Ho (<b>7</b>)-containing compounds by means of single-crystal XRD methods, whereas powder XRD Rietveld refinement was used for the rest of the MOFs. Compounds <b>1</b>–<b>4</b> crystallize in the triclinic space group <i>P</i>1̅, whereas compounds <b>5</b>–<b>9</b> belong to the tetragonal space group <i>P</i>4₃2₁2. Type I and II compounds are 3D frameworks consisting of chains of [LnO₈­(H₂O)] or [LnO₈] polyhedra, respectively, linked by dimethylsuccinate anions, giving rise to I¹O² connectivity. All the compounds were characterized by X-ray diffraction, variable-temperature Fourier transform infrared spectroscopy, and thermal analysis. An exhaustive topological study was performed in comparison with other related compounds. The photoluminescent (PL) properties for compounds <b>3</b>, <b>4</b>, and <b>5</b> have been also explored, indicating that a metal-centered luminescent process takes place

Two Sets of Metal Organic Frameworks along the Lanthanide Series Constructed by 2,3-Dimethylsuccinate: Structures, Topologies, and Strong Emission without Ligand Sensitization

Reactions in aqueous solution under hydrothermal conditions between (±)-2,3-dimethylsuccinic acid and lanthanide chlorides lead to two different isostructural types with chemical formulas [Ln₂­(C₆H₈­O₄)₃­(H₂O)₂] Ln­(III) = Pr–Eu (except Pm) (Type I, compounds <b>1</b>–<b>4</b>) and [Ln₂­(C₆H₈­O₄)₃] Ln­(III) = Tb–Yb (except Tm) (Type II, compounds <b>5</b>–<b>9</b>). The crystal structure has been solved for the Pr (<b>1</b>)-, Sm (<b>3</b>)-, and Ho (<b>7</b>)-containing compounds by means of single-crystal XRD methods, whereas powder XRD Rietveld refinement was used for the rest of the MOFs. Compounds <b>1</b>–<b>4</b> crystallize in the triclinic space group <i>P</i>1̅, whereas compounds <b>5</b>–<b>9</b> belong to the tetragonal space group <i>P</i>4₃2₁2. Type I and II compounds are 3D frameworks consisting of chains of [LnO₈­(H₂O)] or [LnO₈] polyhedra, respectively, linked by dimethylsuccinate anions, giving rise to I¹O² connectivity. All the compounds were characterized by X-ray diffraction, variable-temperature Fourier transform infrared spectroscopy, and thermal analysis. An exhaustive topological study was performed in comparison with other related compounds. The photoluminescent (PL) properties for compounds <b>3</b>, <b>4</b>, and <b>5</b> have been also explored, indicating that a metal-centered luminescent process takes place