Polymorphic phase transformations of 3-chloro-trans-cinnamic acid and its solid solution with 3-bromo-trans-cinnamic acid

Abstract

We have investigated the polymorphic phase transformations above ambient temperature for 3-chloro-trans-cinnamic acid (3-ClCA, CHClO) and a solid solution of 3-ClCA and 3-bromo-trans-cinnamic acid (3-BrCA, CHBrO). At 413 K, the γ polymorph of 3-ClCA transforms to the β polymorph. Interestingly, the structure of the β polymorph of 3-ClCA obtained in this transformation is different from the structure of the β polymorph of 3-BrCA obtained in the corresponding polymorphic transformation from the γ polymorph of 3-BrCA, even though the γ polymorphs of 3-ClCA and 3-BrCA are isostructural. We also report a high-temperature phase transformation from a γ-type structure to a β-type structure for a solid solution of 3-ClCA and 3-BrCA (with a molar ratio close to 1:1). The γ polymorph of the solid solution is isostructural with the γ polymorphs of pure 3-ClCA and pure 3-BrCA, while the β-type structure produced in the phase transformation is structurally similar to the β polymorph of pure 3-BrCA.

Isostructurality in amino molecular salts of two dicarboxylic acids driven by noncovalent synthons

“…One can then fine-tune thermal stability, density, colour, electronic, mechanical and magnetic properties by systematically varying one of the components, functional groups or metal ions of similar size forming solid-solution, without changing the structures. [8][9][10][11][12][13][14][15][16][17] In contrast, cocrystals gained importance especially in the pharmaceutical industry to alter the properties of active pharmaceutical ingredients (APIs) such as solubility, dissolution rate, bioavailability, melting point, stability and mechanical properties. 18,19 Fine tuning of these properties in a systematic and controlled manner can be achieved from isostructural cocrystals.…”

“…One can then fine-tune thermal stability, density, colour, electronic, mechanical and magnetic properties by systematically varying one of the components, functional groups or metal ions of similar size forming solid-solution, without changing the structures. 8–17…”

Polymorphs and Transformations of the Solid Forms of Organic Salts of 5-Sulfosalicylic Acid and Isonicotinamide

“…The diversity of solid forms available to a molecule has crucial implications in industrial applications or pharmaceutical materials, because different forms of an active molecule (e.g., a drug substance) may have significantly different solid-state properties (e.g., solubility, dissolution rate, stability, and bioavailability) . Model materials can play important roles in understanding the structure-property relationship, solid-state transformation behavior, and establishing suitable characterization protocols for such systems. , …”

“…1 Model materials can play important roles in understanding the structure-property relationship, solid-state transformation behavior, and establishing suitable characterization protocols for such systems. 2,3 3-Carboxy-4-hydroxybenzenesulfonic acid, also called 5sulfosalicylic acid (5-SSA) (Scheme 1) contains rich functional groups, such as sulfonic, carboxylic, and phenolic groups, thus making it a potential to form extensive hydrogen bonding interactions as proton donors and acceptors. 4−6 A range of stoichiometric cocrystals or salts of 5-SSA are studied depending on mono-, di-, or tri-anionic species through deprotonation in self-assembly processes.…”