A Contribution to the Solid State Forms of Bis(demethoxy)curcumin: Co-Crystal Screening and Characterization

Bis(demethoxy)curcumin (BDMC) is one of the main active components found in turmeric. Major drawbacks for its usage are its low aqueous solubility, and the challenging separation from other curcuminoids present in turmeric. Co-crystallization can be applied to alter the physicochemical properties of BDMC in a desired manner. A co-crystal screening of BDMC with four hydroxybenzenes was carried out using four different methods of co-crystal production: crystallization from solution by slow solvent evaporation (SSE), and rapid solvent removal (RSR), liquid-assisted grinding (LAG), and crystallization from the melt phase. Two co-crystal phases of BDMC were obtained with pyrogallol (PYR), and hydroxyquinol (HYQ). PYR-BDMC co-crystals can be obtained only from the melt, while HYQ-BDMC co-crystals could also be produced by LAG. Both co-crystals possess an equimolar composition and reveal an incongruent melting behavior. Infrared spectroscopy demonstrated the presence of BDMC in the diketo form in the PYR co-crystals, while it is in a more stable keto-enol form in the HYQ co-crystals. Solubility measurements in ethanol and an ethanol-water mixture revealed an increase of solubility in the latter, but a slightly negative effect on ethanol solubility. These results are useful for a prospective development of crystallization-based separation processes of chemical similar substances through co-crystallization.

Formation of Bi2Ir Nanoparticles in a Microwave-Assisted Polyol Process Revealing the Suboxide Bi4Ir2O

Intermetallic phases are usually obtained by crystallization from the melt. However, phases containing elements with widely different melting and boiling points, as well as nanoparticles, which provide a high specific...

The Influence Technological Aspects to the Formation of Defects in PbI2 Single Crystals

The research of the influence of technological modes has been carried out and the negative influence of contaminating impurities on the lead iodide crystallization process has been grounded. The new technological approach to PbI2 single crystals growth has been proposed, which, unlike traditional methods, is based on increasing of the purity of the source components at the initial stage of technological process. The comparative analysis of the proposed growth technique with other known methods has been made, the efficiency of the purification operation of the Pb and I2 source components for the obtention and properties of PbI2 single crystals has been determined. The main types of defects during PbI2 crystallization from the melt have been analyzed and technological approaches for elimination of the structural violations have been proposed.

Polymorphism of griseofulvin: concomitant crystallization from the melt and a single crystal structure of a metastable polymorph with anomalously large thermal expansion

Single crystal structure of the metastable polymorph of griseofulvin with anomalously large thermal expansion.

A “missing” caesium member in the family of A3Al2P3O12 aluminophosphates

A new caesium aluminophosphate, Cs3Al2P3O12, has been synthesized by spontaneous crystallization from the melt and structurally characterized. The compound crystallizes in the orthorhombic space group Pnma, with a=9.7675(2) Å, b=17.7537(3) Å, c=8.1063(2) Å, V=1405.71(2) Å3, and Z=4. Its crystal structure is based on an open interrupted framework built by alternating AlO4 and PO4 tetrahedra with Cs ions occupying the channels. The Cs3Al2P3O12 framework topology resembles the previously known 4.8.12-net, which has been reported in the [C4N3H16][Al2P3O12] phase prepared by solvothermal synthesis in the presence of diethylenetriamine (DETA). The crystal chemical relationships between the K, Rb, Cs, Tl, [NH4] and [C4N3H16]-members of the A3Al2P3O12 family of compounds are discussed.