Solid‐State Phase Transition of an Inclusion Complex of 5‐Methyl‐2‐pyridone with 1,3,5‐Benzenetricarboxylic Acid

Hirano, Shinya; Toyota, Shinji; Toda, Fumio; Fujii, Kotaro; Uekuasa, Hidehiro

doi:10.1002/anie.200600845

Cited by 27 publications

(15 citation statements)

References 26 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The influence of solvate formation has been studied in a co-crystal system that has been crystal-engineered to undergo photodimerization. It was found that the inclusion of acetonitrile leads to a molecular arrangement allowing photodimerization, while the methanol solvate hinders this . In other studies, inclusion has been utilized to separate xylenes showing a clear preference of one guest over another, or to store volatile guests. , Inclusion complexes have recently become the focus of attention to study the incorporated molecules, either in an unusual conformation, or to obtain structural information on a hard to crystallize compound. , …”

Section: Introductionmentioning

confidence: 99%

Influence of Bio-Isosteric Replacement on the Formation of Templating Methanol and Acetonitrile Solvates in Lophines

Kitchen

Melvin

Najib

et al. 2016

Crystal Growth & Design

View full text Add to dashboard Cite

Bio-isosteric replacement is a frequently used tool in medicinal chemistry. While the pharmacological activity is not influenced by the exchange of substituents, the solid-state characteristics and formation of different crystal forms may well be altered dramatically, jeopardizing the processability and safety of the drug compound. In this study we investigate a series of triphenylimidazole (TPI) derivatives as model compounds with the bio-isosteric exchange of only one halogen position (F, Cl, Br, I). Crystallization from two industrially used solvents (methanol and acetonitrile) reveals solvate formation of all TPIs, for which the basic hydrogen bonded motif does not change. The three-dimensional packing depends on the size of the substituent and changes from fluoroto chloro-and bromo-substitution but remains the same for the larger iodo-substituent. From acetonitrile, only F-TPI and Cl-TPI form an isomorphic channel solvate, which in both cases desolvates reversibly to an isomorphic crystal form. Due to the halogen atom lining of the channels, bromine and iodine are too large to generate a stable packing. This study illustrates the importance of understanding the influence of bio-isosteric substitution on the solid state, in order to best utilize this common tool.

show abstract

Section: Introductionmentioning

confidence: 99%

Influence of Bio-Isosteric Replacement on the Formation of Templating Methanol and Acetonitrile Solvates in Lophines

Kitchen

Melvin

Najib

et al. 2016

Crystal Growth & Design

View full text Add to dashboard Cite

show abstract

“…31 As these techniques can provide structural understanding of polycrystalline product phases obtained from solid-state transformations, they serve an important role in establishing the structural properties of new materials produced in processes such as solid-state grinding (mechanochemical synthesis), solid-state reactions, desolvation processes, polymorphic transformations, and other types of phase transition. 30,[32][33][34][35][36][37][38][39][40][41] In the present paper, we focus on the application of these techniques to understand solid-state transformations associated with the pharmaceutically important material acrinol. Acrinol (2-ethoxy-6,9-diaminoacridine monolactate; here denoted A; Figure 1) is a crystalline material comprising ethacridinium cations and lactate anions in a 1:1 ratio.…”

Section: Introductionmentioning

confidence: 99%

Physicochemical Understanding of Polymorphism and Solid-State Dehydration/Rehydration Processes for the Pharmaceutical Material Acrinol, by Ab Initio Powder X-ray Diffraction Analysis and Other Techniques

et al. 2009

Self Cite

View full text Add to dashboard Cite

The extensively used antibacterial agent acrinol is known to form a monohydrate phase (H) on crystallization from water. We demonstrate here that acrinol also forms two anhydrous polymorphs, denoted form I (AI) and form II (AII). Polymorph AI is obtained directly on heating H, by a solid-state dehydration process, and polymorph AII is obtained subsequently from AI, by a polymorphic transformation. The crystal structures of AI and AII have been determined directly from powder X-ray diffraction data, employing the direct-space genetic algorithm technique for structure solution, followed by Rietveld refinement. From the structural properties of AI and AII, mechanistic aspects of the dehydration process and the polymorphic transformation have been established. From measurements of initial dissolution rates and enthalpies of dissolution, AII is assigned as the thermodynamically stable polymorph, with a monotropic relationship between AI and AII. The hydration properties of AI and AII differ significantly, with hydration of AI occurring at substantially lower relative humidity than AII.

show abstract

“…Upon exposure to acetonitrile, the PPA trihydrate phase dehydrated into anhydrous B phase via the anhydrous A phase, which is the same phase transformation that occurred upon heating. Dehydration upon exposure to acetonitrile vapor is not common, but a few examples are known; ,, polar solvent vapors are known to be able to bring out water molecules from crystals. The PPA trihydrate phase underwent dehydration only by acetonitrile vapor, not by other organic solvent vapors.…”

Section: Resultsmentioning

confidence: 99%

Powder Structure Analysis of Vapochromic Quinolone Antibacterial Agent Crystals

Sakon

Sekine

Uekusa

2016

Crystal Growth & Design

View full text Add to dashboard Cite

Pipemidic acid crystals were found to undergo a reversible color change upon exposure to acetonitrile vapor via dehydration/hydration transformations. The mechanistic aspects of these transformations and the crystalline color change were revealed using X-ray analysis and theoretical calculations. ABSTRACTVapochromic materials, or those that show a reversible color change induced by vapor, are expected to serve as valuable sensors for volatile organic compounds (VOC) or humidity.Crystals of pipemidic acid (PPA), a quinolone antibacterial agent, were found to exhibit vapochromism, as they undergo a reversible color change in the presence of acetonitrile vapor.The colorless trihydrate phase transformed into a yellow anhydrous phase upon exposure to acetonitrile vapor, and returned to the trihydrate phase under high humidity. Ab initio structure determination from powder diffraction and solid state 13 C-NMR measurements revealed that the molecule exists in its zwitterionic form in the colorless trihydrate phase, whereas it is nonzwitterionic in the anhydrous phase because of the rearrangement of hydrogen bonds, due to dehydration in the crystal state. Theoretical calculations revealed that the color change in PPA is due to the change in the molecular electronic state upon taking the non-zwitterionic form, which generates a new HOMO state, thus leading to a HOMO-LUMO transition with a lower energy.

show abstract

Solid‐State Phase Transition of an Inclusion Complex of 5‐Methyl‐2‐pyridone with 1,3,5‐Benzenetricarboxylic Acid

Cited by 27 publications

References 26 publications

Influence of Bio-Isosteric Replacement on the Formation of Templating Methanol and Acetonitrile Solvates in Lophines

Influence of Bio-Isosteric Replacement on the Formation of Templating Methanol and Acetonitrile Solvates in Lophines

Physicochemical Understanding of Polymorphism and Solid-State Dehydration/Rehydration Processes for the Pharmaceutical Material Acrinol, by Ab Initio Powder X-ray Diffraction Analysis and Other Techniques

Powder Structure Analysis of Vapochromic Quinolone Antibacterial Agent Crystals

Contact Info

Product

Resources

About