Polymorphism at hexadecanoic-acid crystals investigated through structural and vibrational studies

Abreu, Diego Candido; Filho, P.F. Façanha; Pinheiro, G.S.; Freire, Paulo; Moreira, S. G. C.; Santos, Auteliano Antunes dos; Sousa, Francisco F. de

doi:10.1016/j.vibspec.2022.103402

Cited by 4 publications

(5 citation statements)

References 42 publications

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“…According to literature, 15,29 the set of bands that appears within the 200-1000 cm −1 spectral range (Fig. 6a and b) is intrinsically characteristic of the B m form of saturated FAs.…”

Section: Hirshfeld Surface Analysissupporting

confidence: 53%

“…It is important to notice that the indices "o" and "m" are associated with two polytypes belonging to the orthorhombic and monoclinic structures, respectively. 29 As mentioned above, the dimers formed through O-H/O]C hydrogen bonds of each pair of molecules inuence the polymorphism at saturated monocarboxylic FAs. Such a phenomenon is duly associated with the molecular congurations into the crystal lattice.…”

Section: Introductionmentioning

confidence: 95%

“…Indeed, when we compared the number and proles of bands from the B m -Raman spectrum with the Raman spectrum of the C form of other saturated FAs, one can notice that such an C polymorphic phase has a spectrum with number of bands minor than the B m form. 15,29 This suggests that the molecular conguration of dimers has an essential role on alterations in the Raman bands related to the CH 2 groups, consequently, the Raman spectra of both polymorphic phases are well distinct. Table 2 presents the Raman modes of the B m form of AA, both experimental and calculated at T = 300 K.…”

Section: Hirshfeld Surface Analysismentioning

confidence: 99%

“…The literature has shown the relation between gauche C-C stretching peak position and chain length for saturated FAs. 15,29 Indeed, the gauche conguration inuences the C-C bonds around COOH groups, which directly connect with hydrogen bonds leading in the Raman spectrum. It is worth noting that in the 30-1000 cm −1 spectral range signicant differences could not be observed between the calculated Raman spectra prole at temperatures of 100 K and 300 K, suggesting a good structural stability for the AA crystal under low-temperature conditions.…”

Section: Hirshfeld Surface Analysismentioning

confidence: 99%

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New polymorphic phase of arachidic acid crystal: structure, intermolecular interactions, low-temperature stability and Raman spectroscopy combined with DFT calculations

Cardoso,

de Oliveira Neto,

Saraiva

et al. 2023

RSC Adv.

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“…According to literature, 15,29 the set of bands that appears within the 200-1000 cm −1 spectral range (Fig. 6a and b) is intrinsically characteristic of the B m form of saturated FAs.…”

Section: Hirshfeld Surface Analysissupporting

confidence: 53%

Section: Introductionmentioning

confidence: 95%

Section: Hirshfeld Surface Analysismentioning

confidence: 99%

Section: Hirshfeld Surface Analysismentioning

confidence: 99%

See 2 more Smart Citations

New polymorphic phase of arachidic acid crystal: structure, intermolecular interactions, low-temperature stability and Raman spectroscopy combined with DFT calculations

Cardoso,

de Oliveira Neto,

Saraiva

et al. 2023

RSC Adv.

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show abstract

“…Filopoulou et al [40] provided an accurate assignation of FTIR spectra of fatty acid and their salts. Abreu et al [41] studied palmitic acid in five different solvents from apolar hexane (favoring folded gauche conformations) to high dipole propanone (favoring the all-trans straight conformation); a systematic trend in the -CH 2 -scissoring band intensities from apolar to polar solvents was observed. Since gauche conformation is possible (2 8 ), the surface to be explored is much more complicated, and this can explain the difficulty of solving its crystal structure.…”

Section: Spectroscopic and Thermal Analysismentioning

confidence: 99%

The Crystal Structure of Calcium Sebacate by X-ray Powder Diffraction Data

2023

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Sodium sebacate salts have several industrial applications as additives, lubricants, and a metal self-healing promoter in general industry, and some derivatives also have wide applications in cosmetics and pharmaceutical fields. Calcium sebacate formation and precipitation can be detrimental for the systems where sodium sebacate is used. It is thus important to investigate their crystallization features. Sodium and calcium sebacate were prepared, purified, and crystallized with different approaches to carry out a full X-ray diffraction powder diffraction structural analysis since suitable single crystals cannot be obtained. The calcium sebacate crystal structure was solved by simulated annealing. Calcium ions form layers connected by straight “all trans” sebacate molecules, a conformation that is also suggested by Fourier-transform infrared spectroscopy FTIR data. Water molecules are caged within calcium layers. The crystal structure is characterized by the calcium layers bent by 10.65° with respect to the plane where sebacate chains lie, different from other dicarboxilic salts, such as cesium suberate, where the layers are perpendicular to the cation planes. The sodium sebacate crystal structure resulted in being impossible to be solved, despite several crystallization attempts and the different data collection approaches. FTIR spectroscopy indicates marked differences between the structures of calcium and sodium sebacate, suggesting a different type of metal coordination by carboxyls. Calcium sebacate shows a bis-bidentate chelating and bridging configuration ((κ2)−(κ1−κ1)−μ3−Carb), while for sodium sebacate, FTIR spectroscopy indicates an ionic interaction between sodium and the carboxyls. A thermogravimetric analysis TGA was carried out to assess the hydration states of the two salts. Calcium sebacate shows, as expected, a total weight loss of ca. 7%, corresponding to the single water molecule located in the crystal structure, while sodium sebacate shows no weight loss before total combustion, indicating that its structure is not hydrated. Scanning electron microscopy SEM images show different morphologies for calcium and sodium salts, probably a consequence of the different interactions at the molecular lever suggested by FTIR and TGA. The used approach can be extended to fatty acid salt in general, a still under-explored field because of the difficulty of growing suitable single crystals.

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Comprehensive analysis of the electronic, thermodynamic, and spectroscopic properties of a Cu(II)-based complex with 1,10-phenanthroline and L-glutamine

Souza Junior,

Oliveira Neto,

Pereira

et al. 2024

Heliyon

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Polymorphism at hexadecanoic-acid crystals investigated through structural and vibrational studies

Cited by 4 publications

References 42 publications

New polymorphic phase of arachidic acid crystal: structure, intermolecular interactions, low-temperature stability and Raman spectroscopy combined with DFT calculations

New polymorphic phase of arachidic acid crystal: structure, intermolecular interactions, low-temperature stability and Raman spectroscopy combined with DFT calculations

The Crystal Structure of Calcium Sebacate by X-ray Powder Diffraction Data

Comprehensive analysis of the electronic, thermodynamic, and spectroscopic properties of a Cu(II)-based complex with 1,10-phenanthroline and L-glutamine

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