Reversibility in a Plastically Flexible Coordination Polymer Crystal: A High-Pressure Study

Single crystals which exhibit mechanical flexibility are promising materials for advanced technological applications. Before such materials can be used, detailed understanding of the mechanisms and structural effects of bending are needed. Coordination polymer single crystal represent a fascinating class of mechanically flexible material; their bending contradicts existing models. Using single crystal X-ray diffraction and microfocus Raman spectroscopy, we study in atomic detail the high-pressure response of the plastically flexible coordination polymer [Zn(μ‐Cl)2(3,5‐dichloropyridine)2]n. In stark contrast to three-point bending, the quasi-hydrostatic compression of the single crystal is completely reversible, even following compression to over 9 GPa. A structural phase transition is observed at ca. 5 GPa. Ab initio DFT calculations show this transition to result from the pressure-induced softening of low frequency vibrations. This phase transition is not observed during three-point bending. Our combined experimental and theoretical high-pressure investigation propose slight compression at low levels of bending. However, our studies provide the first indication of overall disparate mechanical responses of bulk flexibility and quasi-hydrostatic compression. We suspect this to be a general feature of mechanically plastic materials.

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High-pressure reversibility in a plastically flexible coordination polymer crystal

Nature Communications ◽

10.1038/s41467-021-24165-x ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Xiaojiao Liu ◽

Adam A. L. Michalchuk ◽

Biswajit Bhattacharya ◽

Nobuhiro Yasuda ◽

Franziska Emmerling ◽

...

Keyword(s):

Phase Transition ◽

High Pressure ◽

Coordination Polymer ◽

Structural Phase ◽

Low Frequency ◽

Hydrostatic Compression ◽

X Ray Diffraction ◽

X Ray ◽

Three Point Bending ◽

Mechanical Responses

AbstractSingle crystals which exhibit mechanical flexibility are promising materials for advanced technological applications. Before such materials can be used, a detailed understanding of the mechanisms of bending is needed. Using single crystal X-ray diffraction and microfocus Raman spectroscopy, we study in atomic detail the high-pressure response of the plastically flexible coordination polymer [Zn(μ-Cl)2(3,5-dichloropyridine)2]n (1). Contradictory to three-point bending, quasi-hydrostatic compression of (1) is completely reversible, even following compression to over 9 GPa. A structural phase transition is observed at ca. 5 GPa. DFT calculations show this transition to result from the pressure-induced softening of low-frequency vibrations. This phase transition is not observed during three-point-bending. Microfocus synchrotron X-ray diffraction revealed that bending yields significant mosaicity, as opposed to compression. Hence, our studies indicate of overall disparate mechanical responses of bulk flexibility and quasi-hydrostatic compression within the same crystal lattice. We suspect this to be a general feature of plastically bendable materials.

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Pressure-Induced Structural Phase Transition and Metallization in Ga2Se3 up to 40.2 GPa under Non-Hydrostatic and Hydrostatic Environments

Crystals ◽

10.3390/cryst11070746 ◽

2021 ◽

Vol 11 (7) ◽

pp. 746

Author(s):

Meiling Hong ◽

Lidong Dai ◽

Haiying Hu ◽

Xinyu Zhang

Keyword(s):

Phase Transition ◽

Electrical Conductivity ◽

High Pressure ◽

Phase Transformation ◽

Transport Properties ◽

Electrical Transport ◽

Structural Phase ◽

Structure Evolution ◽

Systematic Research ◽

Electrical Transport Properties

A series of investigations on the structural, vibrational, and electrical transport characterizations for Ga2Se3 were conducted up to 40.2 GPa under different hydrostatic environments by virtue of Raman scattering, electrical conductivity, high-resolution transmission electron microscopy, and atomic force microscopy. Upon compression, Ga2Se3 underwent a phase transformation from the zinc-blende to NaCl-type structure at 10.6 GPa under non-hydrostatic conditions, which was manifested by the disappearance of an A mode and the noticeable discontinuities in the pressure-dependent Raman full width at half maximum (FWHMs) and electrical conductivity. Further increasing the pressure to 18.8 GPa, the semiconductor-to-metal phase transition occurred in Ga2Se3, which was evidenced by the high-pressure variable-temperature electrical conductivity measurements. However, the higher structural transition pressure point of 13.2 GPa was detected for Ga2Se3 under hydrostatic conditions, which was possibly related to the protective influence of the pressure medium. Upon decompression, the phase transformation and metallization were found to be reversible but existed in the large pressure hysteresis effect under different hydrostatic environments. Systematic research on the high-pressure structural and electrical transport properties for Ga2Se3 would be helpful to further explore the crystal structure evolution and electrical transport properties for other A2B3-type compounds.

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High-pressure structural phase transition and metallization in Ga2S3 under non-hydrostatic and hydrostatic conditions up to 36.4 GPa

Journal of Materials Chemistry C ◽

10.1039/d0tc06004f ◽

2021 ◽

Author(s):

Linfei Yang ◽

Jianjun Jiang ◽

Lidong Dai ◽

Haiying Hu ◽

Meiling Hong ◽

...

Keyword(s):

Phase Transition ◽

Raman Spectroscopy ◽

High Pressure ◽

Structural Properties ◽

Structural Phase Transition ◽

First Principles ◽

Theoretical Calculations ◽

Structural Phase

The vibrational, electrical and structural properties of Ga2S3 were explored by Raman spectroscopy, EC measurements, HRTEM and First-principles theoretical calculations under different pressure environments up to 36.4 GPa.

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Pressure-induced Jahn-Teller Switch in the Homoleptic Hybrid Perovskite [(CH3)2NH2]Cu(HCOO)3: Orbital Reordering by Unconventional Degrees of Freedom

Journal of Materials Chemistry C ◽

10.1039/d1tc01966j ◽

2021 ◽

Author(s):

Rebecca Scatena ◽

Michał Andrzejewski ◽

Roger D Johnson ◽

Piero Macchi

Keyword(s):

Phase Transition ◽

High Pressure ◽

Coordination Polymer ◽

Degrees Of Freedom ◽

X Ray Diffraction ◽

X Ray ◽

Hybrid Perovskite ◽

Jahn Teller

Through in-situ, high-pressure x-ray diffraction experiments we have shown that the homoleptic perovskite-like coordination polymer [(CH3)2NH2]Cu(HCOO)3 undergoes a pressure-induced orbital reordering phase transition above 5.20 GPa. This transition is distinct...

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The structural phase transition of ammonia borane under high pressure

International Journal of Hydrogen Energy ◽

10.1016/j.ijhydene.2020.09.126 ◽

2020 ◽

Vol 45 (58) ◽

pp. 33047-33058

Author(s):

Lan-Ting Shi ◽

Cui-E Hu ◽

Alfonso Muñoz ◽

Lin-Xiang Ji ◽

Yao-Yao Huang ◽

...

Keyword(s):

Phase Transition ◽

High Pressure ◽

Structural Phase Transition ◽

Structural Phase ◽

Ammonia Borane

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ChemInform Abstract: RAMAN STUDY OF N-NITRODIMETHYLAMINE SINGLE CRYSTAL. EVIDENCE FOR A STRUCTURAL PHASE TRANSITION

Chemischer Informationsdienst ◽

10.1002/chin.198014047 ◽

1980 ◽

Vol 11 (14) ◽

Author(s):

M. REY-LAFON

Keyword(s):

Phase Transition ◽

Single Crystal ◽

Structural Phase Transition ◽

Structural Phase ◽

Raman Study

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Phase transition and proton ordering at 50 K in 3-(pyridin-4-yl)pentane-2,4-dione

Acta Crystallographica Section B Structural Science Crystal Engineering and Materials ◽

10.1107/s2052520617015591 ◽

2017 ◽

Vol 73 (6) ◽

pp. 1172-1178 ◽

Cited By ~ 4

Author(s):

Khai-Nghi Truong ◽

Carina Merkens ◽

Martin Meven ◽

Björn Faßbänder ◽

Richard Dronskowski ◽

...

Keyword(s):

Phase Transition ◽

Low Temperature ◽

Single Crystal ◽

Structural Phase ◽

Pyridyl Ring ◽

Temperature Phase ◽

Crystallographic Axis ◽

Temperature Phase Transition ◽

Intramolecular Hydrogen ◽

Low Temperature Phase

Single-crystal neutron diffraction experiments at 100 and 2.5 K have been performed to determine the structure of 3-(pyridin-4-yl)pentane-2,4-dione (HacacPy) with respect to its protonation pattern and to monitor a low-temperature phase transition. Solid HacacPy exists as the enol tautomer with a short intramolecular hydrogen bond. At 100 K, its donor···acceptor distance is 2.450 (8) Å and the compound adopts space group C2/c, with the N and para-C atoms of the pyridyl ring and the central C of the acetylacetone substituent on the twofold crystallographic axis. As a consequence of the axial symmetry, the bridging hydrogen is disordered over two symmetrically equivalent positions, and the carbon–oxygen bond distances adopt intermediate values between single and double bonds. Upon cooling, a structural phase transition to the t 2 subgroup P\bar 1 occurs; the resulting twins show an ordered acetylacetone moiety. The phase transition is fully reversible but associated with an appreciable hysteresis in the large single crystal under study: transition to the low-temperature phase requires several hours at 2.5 K and heating to 80 K is required to revert the transformation. No significant hysteresis is observed in a powder sample, in agreement with the second-order nature of the phase transition.

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