Crystal Growth of Salicylic Acid in Organic Solvents

Liu, Jia; Svärd, Michael; Rasmuson, Åke C.

doi:10.1021/acs.cgd.6b01415

Cited by 24 publications

(54 citation statements)

References 38 publications

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“…Since the activation energies measured for the fluconazole MH at the beginning of the process are similar in magnitude to those reported for various other crystal growth and nucleation processes, − it is reasonable to assume that nucleation and growth of the anhydrous form, AH-C, is the dominant process controlling the kinetics of fluconazole MH dehydration at the beginning of the process. As dehydration progresses, the activation energy decreases to 38 kJ/mol, which is in line with the strength of approximately two hydrogen bonds.…”

Section: Resultssupporting

confidence: 52%

“…There is limited data for the influence of conversion fraction on Ea, however a decrease in Ea, with an increase in conversion fraction, was found for nedocromil Na trihydrate (80 to 60 kJ/mol) 64 and mildronate dihydrate (105 to 75 kJ/mol). 23 Since the activation energies measured for the fluconazole MH at the beginning of the process are similar in magnitude to those reported for various other crystal growth and nucleation processes, [65][66][67][68][69][70][71] it is reasonable to assume that nucleation and growth of the anhydrous form, AH-C, is the dominant process controlling the kinetics of fluconazole MH dehydration at the beginning of the process. As dehydration progresses, the activation energy decreases to 38 kJ/mol which is in line with the strength of approximately two hydrogen bonds.…”

Section: Activation Energies Of the Dehydration Processsupporting

confidence: 62%

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Conformational Change Initiates Dehydration in Fluconazole Monohydrate

Basford

Cameron

Cruz‐Cabeza

2020

Crystal Growth & Design

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Experimental and computational techniques have been used in combination, to monitor the dehydration process of fluconazole monohydrate (MH), this unveiling the dehydration mechanism at the molecular level. Experimentally, dehydration was observed to start at around 55 °C and complete around 100 °C, with metastable Pbca, Z'=1 polymorph (AH-C) as the sole product of dehydration (as determined by in-situ hot stage PXRD). Conformational and structural changes were identified as key in the initiation and progression of the dehydration process. Thermal expansion is most significant along the c-axis, with molecular dynamic (MD) simulations and experimental observations identifying that water migrates through the MH crystal lattice within the plane perpendicular to that direction. Water was found to migrate within the (001) plane along both the a and b-axis directions. The MD simulations revealed that water was not able to migrate within the lattice at room temperature. Migration at 70°C (342K) was plausible, but only after the hydroxyl group undergoes conformational change. The conformational change, around the hydroxyl group, is key to both the weakening of the fluconazole-water hydrogen bonding, found in the MH structure, and the promotion of the fluconazole-fluconazole hydrogen bonding, required for the formation of polymorph AH-C.

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Section: Resultssupporting

confidence: 52%

Section: Activation Energies Of the Dehydration Processsupporting

confidence: 62%

Conformational Change Initiates Dehydration in Fluconazole Monohydrate

Basford

Cameron

Cruz‐Cabeza

2020

Crystal Growth & Design

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“…Geometry optimization was performed with the conjugate-gradient algorithm with all atoms and unit cell shapes and dimensions allowed to relax. The initial geometry was taken from the following references: SA monoclinic, 34,35 3NBZ monoclinic, 36 1:1 and 2:2 cocrystals (from this work). The interaction energy E int is calculated as the difference between the energies of the cocrystals (composition of N (SA): N (3NBZ) and the pure crystals and is given per molecule (eq 1), int 3…”

Section: Theoretical Calculationsmentioning

confidence: 99%

X-Ray Diffraction and Theoretical Calculation–Supported Formation of Polymorphic Cocrystals Discovered Through Thermal Methods: A Case Study

Zhou

Calatayud

Contreras‐García

et al. 2019

Journal of Pharmaceutical Sciences

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Polymorphism commonly exists in the preparation of cocrystals and has attracted widespread attention from both the pharmaceutical industry and academia. However, few studies have examined how to discover polymorphic cocrystals and their potential formation mechanism. In this study, we report the novel discovery of salicylic acid: 3-nitrobenzamide (SA-3NBZ) polymorphic cocrystals by thermal methods. The formation mechanism is elucidated based on theoretical calculations. SA-3NBZ polymorphic cocrystals with molar ratio of 1:1 and 2:2 were discovered using the combination of differential scanning calorimetry (DSC) and hot stage microscopy (HSM). Single crystal X-ray diffraction analysis confirmed this discovery. Density functional theory (DFT) calculations corrected with dispersion were conducted to illustrate the energetic stabilization of SA polymorphic cocrystals. Compared with the starting materials, formation of the cocrystals at 1:1 and 2:2 present a weak stabilization with overall energy reduction of -0.01 and -0.05 eV/molecule, respectively. The calculated non-covalent interactions index (NCI) further suggests that intralayer hydrogen bonds and van der Waals forces contribute to these weak interactions. The DFT calculations are in good agreement with the X-ray diffraction data. Hence, thermal analysis is a simple and reliable method to discover polymorphic cocrystals.

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“…Our previous research on crystals containing acridine derivatives [ 10 , 11 , 12 , 13 ] shows that benzoic acids are good candidates for the preparation of multi-component crystals containing these APIs. Moreover, it is known that the use of different solvents during the crystallization process provide the yield of a different solvates of multi-component crystals involving APIs [ 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 ], including acridine derivatives [ 24 ]. Taking into account the structures of crystals, there are two reasons for the formation of API solvates [ 25 , 26 ].…”

Section: Introductionmentioning

confidence: 99%

The Influence of Solvent on the Crystal Packing of Ethacridinium Phthalate Solvates

Mirocki¹,

Sikorski²

2020

Materials

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The synthesis, structural characterization and influence of solvents on the crystal packing of solvated complexes of ethacridine with phthalic acid: 6,9-diamino-2-ethoxyacridinium phthalate methanol solvate (1), 6,9-diamino-2-ethoxyacridinium phthalate ethanol solvate (2), 6,9-diamino-2-ethoxyacridinium phthalate isobutanol solvate (3), and 6,9-diamino-2-ethoxyacridinium phthalate tert-butanol solvate monohydrate (4) are described in this article. Single-crystal XRD measurements revealed that the compounds 1–4 crystallized in the triclinic P-1 space group, and the 6,9-diamino-2-ethoxyacridinium cations, phthalic acid anions and solvent molecules interact via strong N–H···O, O–H···O, C–H···O hydrogen bonds, and C–H···π and π–π interactions to form different types of basic structural motifs, such as: heterotetramer bis[···cation···anion···] in compound 1 and 2, heterohexamer bis[···cation···alcohol···anion···] in compound 3, and heterohexamer bis[···cation···water···anion···] in compound 4. Presence of solvents molecule(s) in the crystals causes different supramolecular synthons to be obtained and thus has an influence on the crystal packing of the compounds analyzed.

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Crystal Growth of Salicylic Acid in Organic Solvents

Abstract: Access to the published version may require subscription. N.B. When citing this work, cite the original published paper.

Cited by 24 publications

References 38 publications

Conformational Change Initiates Dehydration in Fluconazole Monohydrate

Conformational Change Initiates Dehydration in Fluconazole Monohydrate

X-Ray Diffraction and Theoretical Calculation–Supported Formation of Polymorphic Cocrystals Discovered Through Thermal Methods: A Case Study

The Influence of Solvent on the Crystal Packing of Ethacridinium Phthalate Solvates

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