Carboxylic acid–pyridine supramolecular heterocatemer in a co-crystal

Sudhakar, P.; Srivijaya, R.; Sreekanth, B.; Jayanthi, Prisilla; Vishweshwar, Peddy; Babu, Moses J.; Vyas, K.; Iqbal, Javed

doi:10.1016/j.molstruc.2007.10.003

Cited by 12 publications

(6 citation statements)

References 17 publications

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“…Analysis of the Cambridge Structural Database (CSD) data shows a 91% probability of hydrogen bond formation between compounds containing the pyridyl ring and a carboxylic acid . Therefore, cocrystallization of the antituberculosis drug isoniazid (isonicotinic acid hydrazide), a pyridyl group containing compound, with carboxylic acids is expected to give O–H···N hydrogen bonded cocrystals. − …”

Section: Introductionmentioning

confidence: 99%

Crystal and Molecular Structure and Stability of Isoniazid Cocrystals with Selected Carboxylic Acids

Sarceviča

Orola

Veidis

et al. 2013

Crystal Growth & Design

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Reaction of isoniazid with benzoic acid, sebacic acid, suberic acid, and cinnamic acid results in formation of cocrystals. Two polymorphs of isoniazid–suberic acid and two polymorphs of isoniazid–cinnamic acid cocrystals were isolated. Crystal structure analysis shows the presence of a pyridine–carboxylic acid synthon in the studied cocrystals. The hydrazide group of isoniazid participates in N–H···O and N–H···N hydrogen bond formation, producing different supramolecular synthons. The stability study of isoniazid cocrystals has been performed over a 22 week period. A comparison of melting points of isoniazid–dicarboxylic acid 2:1 cocrystals shows the decrease of melting point with an increasing length of the acid. Solubility of isoniazid–carboxylic acid cocrystals tends to increase with increasing solubility of the acid.

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Section: Introductionmentioning

confidence: 99%

Crystal and Molecular Structure and Stability of Isoniazid Cocrystals with Selected Carboxylic Acids

Sarceviča

Orola

Veidis

et al. 2013

Crystal Growth & Design

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“…Co-dissolving P4VP and FDA in dry methanol leads to the selfassembly of FDA with P4VP through hydrogen bonding, as seen in cocrystals 49 affording uniform spatial distribution of the FDA molecules (Figure 1). The homo polymer P4VP (M n = 60 000) and FDA in 1:1 molar ratio of pyridine to carboxylic acid groups are dissolved in anhydrous methanol at room temperature.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Supramolecular Architecture of Molecular-Level-Ordered 1,1′-Ferrocenedicarboxylic Acid with Poly(4-vinylpyridine) for Bulk Magnetic Coupling

Lee

Shin

Sung

et al. 2019

ACS Appl. Polym. Mater.

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Molecular-level ordering provides a powerful approach to enhancing the properties of materials. However, the precise arrangement of molecules in a bulk material is a considerable challenge. To overcome such limitations, hydrogen bonding-directed self-assembly has drawn a lot of attention due to its facile nature in controlling molecular-level order. In this study, we report ordering of the magnetic Fe centers achieved through hydrogen bonding between poly(4-vinylpyridine) (P4VP, MW 60 kDa) and 1,1′-ferrocenedicarboxylic acid (FDA). Co-dissolving P4VP and FDA in dry methanol leads to P4VP–FDA showing an unprecedented degree of order for both FDA and the polymer chain. Such an event of mutual assistance between a dicarboxylic acid and a high molecular weight polymer chain in building the ordered supramolecular architecture is rare. FDA is uniformly distributed in an ordered polymer matrix, with each Fe center in P4VP–FDA linked at the molecular-level through polymeric bridges in a face-centered cubic structure. The P4VP–FDA in the bulk form show a large enhancement of magnetic moment with a paramagnetic resonance and asymmetric current–voltage characteristics similar to the properties of electrode–FDA–electrode architecture.

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“…25 Using chemically tuned heterosynthons, one might control cocrystallization, and hence, their active pharmaceutical ingredient (API) properties can be improved. 26 For the selective isolation of salts or cocrystals, an appropriate counterion is chosen on the basis of the ΔpK a [pK a (base) − pK a (acid)] criterion that has emerged as a useful guideline for the drug industry. 27,28 It has been observed that, when the ΔpK a is large enough, salt formation is common, hence a "rule of thumb" stating that salts would be formed if ΔpK a [pK a (base) − pK a (acid)] ≥ 2−3 during a particular acid−base solid-state reaction.…”

Section: ■ Introductionmentioning

confidence: 99%

“…The formation of the cocrystal or salt is governed by the nature of synthons, categorized as homosynthons and heterosynthons depending on the type of molecular constituents . Using chemically tuned heterosynthons, one might control cocrystallization, and hence, their active pharmaceutical ingredient (API) properties can be improved …”

Section: Introductionmentioning

confidence: 99%

Nonequimolar Mixture of Organic Acids and Bases: An Exception to the Rule of Thumb for Salt or Cocrystal

Pratik

Datta

2016

J. Phys. Chem. B

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Formation of salt and/or cocrystal from organic acid-base mixtures has significant consequences in the pharmaceutical industry and its related intellectual property rights (IPR). On the basis of calculations using periodic dispersion corrected DFT (DFT-D2) on formic acid-pyridine adduct, we have demonstrated that an equimolar stoichiometric ratio (1:1) exists as a neutral cocrystal. On the other hand, the nonequimolar stoichiometry (4:1) readily forms an ionic salt. While the former result is in agreement with the ΔpKa rule between the base and the acid, the latter is not. Calculations reveal that, within the equimolar manifold (n:n; n = 1-4), the mixture exists as a hydrogen bonded complex in a cocrystal-like environment. However, the nonequimolar mixture in a ratio of 5:1 and above readily forms salt-like structures. Because of the cooperative nature of hydrogen bonding, the strength of the O-H···N hydrogen bond increases and eventually transforms into O(-)···H-N(+) (complete proton transfer) as the ratio of formic acid increases and forms salt as experimentally observed. Clearly, an enhanced polarization of formic acid on aggregation increases its acidity and, hence, facilitates its transfer to pyridine. Motion of the proton from formic acid to pyridine is shown to follow a relay mechanism wherein the proton that is far away from pyridine is ionized and is subsequently transferred to pyridine via hopping across the neutral formic acid molecules (Grotthuss type pathway). The dynamic nature of protons in the condensed phase is also evident for cocrystals as the barrier of intramolecular proton migration in formic acid (leading to tautomerism), ΔH(⧧)tautomer = 17.1 kcal/mol in the presence of pyridine is half of that in free formic acid (cf. ΔH(⧧)tautomer = 34.2 kcal/mol). We show that an acid-base reaction can be altered in the solid state to selectively form a cocrystal or salt depending on the strength and nature of aggregation.

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Carboxylic acid–pyridine supramolecular heterocatemer in a co-crystal

Cited by 12 publications

References 17 publications

Crystal and Molecular Structure and Stability of Isoniazid Cocrystals with Selected Carboxylic Acids

Crystal and Molecular Structure and Stability of Isoniazid Cocrystals with Selected Carboxylic Acids

Supramolecular Architecture of Molecular-Level-Ordered 1,1′-Ferrocenedicarboxylic Acid with Poly(4-vinylpyridine) for Bulk Magnetic Coupling

Nonequimolar Mixture of Organic Acids and Bases: An Exception to the Rule of Thumb for Salt or Cocrystal

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