Pressure-induced transformations and high-pressure behaviour in cyanoadamantane plastic crystal

Hédoux, Alain; Guinet, Yannick; Derollez, Patrick; willart, Jean-François; Capet, Frédéric; Descamps, Marc

doi:10.1088/0953-8984/15/49/033

Cited by 7 publications

(10 citation statements)

References 39 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The spectrum of form I shows that several modes shift to lower frequency on heating, which reverses on cooling, which may be attributed to the changes in thermal vibrations . There is no evidence from the THz-Raman data of any transient amorphous or disordered intermediate phases during the heating/cooling cycles …”

Section: Resultsmentioning

confidence: 92%

“…56 There is no evidence from the THz-Raman data of any transient amorphous or disordered intermediate phases during the heating/cooling cycles. 57 While the THz Raman data are rich in information corresponding to both inter-and intramolecular vibrations, extracting relevant information is challenging without exploiting the recent development of computational methods. 58,59 Theoretical harmonic phonon dispersion curves along highsymmetry paths of the Brillouin zone were calculated using periodic electronic structure (PBE-TS) methods (see Supporting Information, Section 2.4).…”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Reversible, Two-Step Single-Crystal to Single-Crystal Phase Transitions between Desloratadine Forms I, II, and III

Srirambhatla

Guo

Dawson

et al. 2020

Crystal Growth & Design

View full text Add to dashboard Cite

Single-crystal to single-crystal polymorphic transformations in molecular solids are relatively rare, with changes in crystal structure more commonly leading to destruction of the parent crystal. However, the structural basis for such transitions is of considerable interest given the changes in material properties that can result. The antihistamine desloratadine displays a two-step, reversible single-crystal to single-crystal phase transition during heating/cooling cycles between three conformational polymorphs: the low temperature form I, a polytypic intermediate form II, and the high temperature form III. The two-step transition involves a sequential flipping of the piperidine rings of desloratadine molecules in the crystals, which induce reversible micrometer-scale contraction on heating and expansion on cooling of the largest face of a desloratadine single crystal. Distinct, slow-moving phase boundaries, originating on the (001) face of the crystal, were observed sweeping through the entire crystal in hot-stage microscopy, suggesting a single nucleation event. Computational spectroscopy, using periodic DFT-D phonon calculations, reproduces the experimental variable-temperatureTHz-Raman spectra and rules out the possibility of the phase transformations occurring via any classical soft mode. A combination of variable-temperature powder X-ray diffraction, solid-state NMR, and computational spectroscopy provides a detailed molecular description of the phase transitions, indicating a first-order diffusionless process between I → II and II → III, wherein both conformational changes and lattice distortions occur simultaneously in the crystal lattice. The study indicates that a nucleation and growth mechanism is compatible with concerted movements producing a conformational change in organic molecular crystals.

show abstract

Section: Resultsmentioning

confidence: 92%

Section: Resultsmentioning

confidence: 99%

Reversible, Two-Step Single-Crystal to Single-Crystal Phase Transitions between Desloratadine Forms I, II, and III

Srirambhatla

Guo

Dawson

et al. 2020

Crystal Growth & Design

View full text Add to dashboard Cite

show abstract

“…1 GPa. This strong discrepancy in the behavior of intermolecular and intramolecular vibrations reflects the disparity between the internal and external modes in molecular compounds [40][41][42][43]. Below 1 GPa, the Raman spectrum of ␥-IMC is dominated by a hard pressure dependence of the lattice modes contrasting to the analyzed internal modes.…”

mentioning

confidence: 98%

Evidence for a high-density amorphous form in indomethacin from Raman scattering investigations

et al. 2008

Self Cite

View full text Add to dashboard Cite

Pressure-induced transformation of ␥-IMC ͓1-͑p-chlorobenzoyl͒-5-methoxy-2-methylindole-3-acetic acid͔ is analyzed from Raman scattering investigations in the low-frequency range of 10-250 cm −1 and the high frequency region between 1550 and 1750 cm −1 , where C v O stretching vibrations are usually observed. At room temperature, by pressurization from atmospheric pressure up to 4 GPa, ␥-IMC undergoes a collapse transformation into a high-pressure crystalline form, induced by large rearrangement in the hydrogen-bonded network associated with molecular conformational changes. The Raman spectrum of the high-pressure crystal is similar to that of the ␣ form, which is denser than the ␥ form and metastable with respect to ␥-IMC at atmospheric pressure. Upon further compression a solid-state amorphization is observed via the breakdown of hydrogen bonds. The Raman line shape of the high-pressure amorphous form is different from that of the vitreous state ͑or thermal glass obtained by quenching the liquid͒, suggesting the existence of a high-density amorphous state. By release of pressure, this high-density amorphous state transforms into the thermal glass. This transformation can be interpreted as a transformation between a high-density amorphous to a low-density amorphous state, which could be associated with a polyamorphic transformation.

show abstract

“…The experimental temperature and pressure-dependent THz-TDS spectra of camphor were obtained using a custombuilt THz-TDS spectrometer [21] (see Supplemental Material [35]). The THz-TDS spectrum of the LT phase contains a number of resolvable features, while the spectrum of the HT phase is essentially featureless, a common trait of disordered solids [36,37]. While the LT phase has had its spectrum assigned previously [20], the spectrum of the HT phase (and in fact, the low-frequency vibrational spectra of disordered solids in general) has not been quantitatively assigned with quantum-mechanical accuracy and atomiclevel precision to date.…”

mentioning

confidence: 99%

Uncovering the Connection Between Low-Frequency Dynamics and Phase Transformation Phenomena in Molecular Solids

et al. 2018

View full text Add to dashboard Cite

The low-frequency motions of molecules in the condensed phase have been shown to be vital to a large number of physical properties and processes. However, in the case of disordered systems, it is often difficult to elucidate the atomic-level details surrounding these phenomena. In this work, we have performed an extensive experimental and computational study on the molecular solid camphor, which exhibits a rich and complex structure-dynamics relationship, and undergoes an order-disorder transition near ambient conditions. The combination of x-ray diffraction, variable temperature and pressure terahertz time-domain spectroscopy, ab initio molecular dynamics, and periodic density functional theory calculations enables a complete picture of the phase transition to be obtained, inclusive of mechanistic, structural, and thermodynamic phenomena. Additionally, the low-frequency vibrations of a disordered solid are characterized for the first time with atomic-level precision, uncovering a clear link between such motions and the phase transformation. Overall, this combination of methods allows for significant details to be obtained for disordered solids and the associated transformations, providing a framework that can be directly applied for a wide range of similar systems.

show abstract

Pressure-induced transformations and high-pressure behaviour in cyanoadamantane plastic crystal

Cited by 7 publications

References 39 publications

Reversible, Two-Step Single-Crystal to Single-Crystal Phase Transitions between Desloratadine Forms I, II, and III

Reversible, Two-Step Single-Crystal to Single-Crystal Phase Transitions between Desloratadine Forms I, II, and III

Evidence for a high-density amorphous form in indomethacin from Raman scattering investigations

Uncovering the Connection Between Low-Frequency Dynamics and Phase Transformation Phenomena in Molecular Solids

Contact Info

Product

Resources

About