Exploring Salts of Memantine with Inorganic Anions: From Polymorphism and Solid-State Transitions to Potential for Drug Formulations.

This study examines pharmaceutically acceptable inorganic salts of memantine, specifically focusing on hydrogen sulfate, sulfate, and dihydrogen phosphate salts, with the aim of finding alternatives to the commonly used chloride salt in the treatment of Alzheimer's disease. Through comprehensive solid-state characterization, including powder X-ray diffraction, thermal analysis, and solubility testing, we unveil complex polymorphic behaviors, reversible solid-state transitions, and significant differences in solubility and stability among the salts. Notably, the hydrogen sulfate salt emerges as a promising candidate for drug formulations, offering improved solubility, nonhygroscopic nature, and favorable morphological characteristics compared to the existing chloride salt.

Perhalogenated Anilines as Bifunctional Donors of Hydrogen and Halogen Bonds in Cocrystals with Ditopic Nitrogen-Containing Acceptors.

In this study, we examine the experimental and theoretical capabilities of two perhalogenated anilines, 2,3,5,6-tetrafluoro-4-bromoaniline () and 2,3,5,6-tetrafluoro-4-iodoaniline () as hydrogen and halogen bond donors. A series of 11 cocrystals derived from the two anilines and selected ditopic nitrogen-containing acceptors (4,4'-bipyridine, 1,2-bis(4-pyridyl)ethane, and 1,4-diazabicyclo[2.2.

Molybdenum Complexes Derived from 2-Hydroxy-5-nitrobenzaldehyde and Benzhydrazide as Potential Oxidation Catalysts and Semiconductors.

This study aimed to synthesize molybdenum complexes coordinated with an aroyl hydrazone-type ligand (HL), which was generated through the condensation of 2-hydroxy-5-nitrobenzaldehyde with benzhydrazide. The synthesis yielded two types of mononuclear complexes, specifically [MoO(L)(MeOH)] and [MoO(L)(HO)], as well as a bipyridine-bridged dinuclear complex, [(MoO(L))(4,4'-bpy)]. Those entities were thoroughly characterized using a suite of analytical techniques, including attenuated total reflectance infrared spectroscopy (IR-ATR), elemental analysis (EA), thermogravimetric analysis (TGA), and single-crystal X-ray diffraction (SCXRD).

Supramolecular Handshakes: Characterization of Urea-Carboxylate Interactions Within Calixarene Frameworks.

The research of molecular capsules offers high application potential and numerous benefits in various fields. With the aim of forming supramolecular capsules which can be reversibly assembled and dissociated by simple external stimuli, we studied interactions between calixarenes containing urea and carboxylate moieties. To this end two ureido-derivatives of p-tert-butylcalix[4]arene comprising phenylureido-moieties and diacetate-calix[4]arenes were prepared.

Preparative and Catalytic Properties of Mo Mononuclear and Metallosupramolecular Coordination Assemblies Bearing Hydrazonato Ligands.

A series of polynuclear, dinuclear, and mononuclear Mo(VI) complexes were synthesized with the hydrazonato ligands derived from 5-methoxysalicylaldehyde and the corresponding hydrazides (isonicotinic hydrazide (HL), nicotinic hydrazide (HL), 2-aminobenzhydrazide (HL), or 4-aminobenzhydrazide (HL)). The metallosupramolecular compounds obtained from non-coordinating solvents, [MoO(L)] ( and ) and [MoO(L)] ( and ), formed infinite structures and metallacycles, respectively. By blocking two coordination sites with cis-dioxo ligands, the molybdenum centers have three coordination sites occupied by the donor atoms from the rigid hydrazone ligands and one by the N atom of pyridyl or amine-functionalized ligand subcomponents from the neighboring Mo building units.