Pressure-induced Diels-Alder reactions in CH - CF cocrystal towards graphane structure

Wang, Y.*; Dong, X.*; Tang, X.*; Zheng, H.*; Li, K.*; Lin, X.*; Fang, L.*; Sun, G.*; Chen, X.*; Xie, L.*; et al.

Angewandte Chemie; International Edition, 58(5), p.1468 - 1473, 2019/01

https://doi.org/10.1002/anie.201813120

Pressure-induced polymerization (PIP) of aromatics is a novel method to construct sp-carbon frameworks, and nanothreads with diamond-like structures were synthesized by compressing benzene and its derivatives. Here by compressing benzene-hexafluorobenzene cocrystal(CHCF), we identified H-F-substituted graphane with a layered structure in the PIP product. Based on the crystal structure determined from the in situ neutron diffraction and the intermediate products identified by the gas chromatography-mass spectrum, we found that at 20 GPa CHCF forms tilted columns with benzene and hexafluorobenzene stacked alternatively, which leads to a [4+2] polymer, and then transfers to short-range ordered hydrogenated-fluorinated graphane. The reaction process contains [4+2] Diels-Alder, retro-Diels-Alder, and 1-1' coupling, and the former is the key reaction in the PIP. Our studies confirmed the elemental reactions of the CHCF for the first time, which provides a novel insight into the PIP of aromatics.

Bulk moduli and equations of state of ice VII and ice VIII

Klotz, S.*; Komatsu, Kazuki*; Kagi, Hiroyuki*; Kunc, K.*; Sano, Asami; Machida, Shinichi*; Hattori, Takanori

Physical Review B, 95(17), p.174111_1 - 174111_7, 2017/05

AA2017-0082.pdf:0.79MB

https://doi.org/10.1103/PhysRevB.95.174111

The compression behaviour of deuterated ice VII and VIII was investigated by high pressure neutron scattering in the pressure range 2-13.7 GPa between 93 K and 300 K. We establish equations-of-state which contain accurate values for the bulk moduli B, their pressure derivatives B', as well as the ambient pressure volumina V. These equations-of-state hold over a large part of the stability domain of ice VII, by comparison with available X-ray data, and to at least 13 GPa for ice VIII. They are indistinguishable at low pressures, but beyond 7 GPa and at low temperatures ice VIII appears to become stiffer than expected. This might be related to an anomalous phonon hardening observed previously in ice VIII in this range [D.D. Klug et al., Physical Review B, 70, 144113 (2004)].

High-Pressure Neutron Diffractometer PLANET

Hattori, Takanori

Hamon, 25(3), p.231 - 237, 2015/08

PLANET is a time-of-flight (TOF) neutron beamline dedicated to high-pressure experiments. By using several high-pressure devices, neutron diffraction patterns are obtainable at wide PT condition, ranging from 0-20 GPa and 77 K-2000 K. To obtain clean pattern, the beamline is equipped with the incident slits and receiving collimators to eliminate parasitic scattering from the high-pressure cell. The high performance of the diffractometer with the resolution (d/d = 0.6%) and the accessible d-spacing range (0.2-8.4 ) together with low-parasitic scattering characteristics enables precise structure determination of crystals and liquids even under high-pressure and high-temperature conditions.

Application and outlook of the pulsed neutron beam at J-PARC, 3; Introduction of high-pressure science and surface/interface analysis at J-PARC

Hattori, Takanori; Akutsu, Kazuhiro*; Suzuki, Junichi*

Bunseki, 2015(2), p.58 - 64, 2015/02

http://ci.nii.ac.jp/naid/40020360800

In the J-PARC MLF, 18 beamlines has been constructed and many studies on scientific and industrial use have been performed. This paper introduces the high-pressure science at high-pressure neutron diffractometer "PLANET" and surface/interface structure analysis at vertical sample geometry polarized neutron reflectometer "SHARAKU".

Phase transitions and hydrogen bonding in deuterated calcium hydroxide; High-pressure and high-temperature neutron diffraction measurements

Iizuka, Riko*; Komatsu, Kazuki*; Kagi, Hiroyuki*; Nagai, Takaya*; Sano, Asami; Hattori, Takanori; Goto, Hirotada*; Yagi, Takehiko*

Journal of Solid State Chemistry, 218, p.95 - 102, 2014/10

https://doi.org/10.1016/j.jssc.2014.06.010

In situ neutron diffraction measurements combined with the pulsed neutron source at the Japan Proton Accelerator Research Complex (J-PARC) were conducted on high-pressure polymorphs of deuterated portlandite (Ca(OD)) using a Paris-Edinburgh cell and a multi-anvil press. The atomic positions including hydrogen for the unquenchable high-pressure phase at room temperature (phase II') were first clarified. The bent hydrogen bonds under high pressure were consistent with results from Raman spectroscopy. The structure of the high-pressure and high-temperature phase (Phase II) was concordant with that observed previously by another group for a recovered sample. The observations elucidate the phase transition mechanism among the polymorphs, which involves the sliding of CaO polyhedral layers, position modulations of Ca atoms, and recombination of Ca-O bonds accompanied by the reorientation of hydrogen to form more stable hydrogen bonds.

High-pressure neutron study on silica glass at J-PARC high-pressure neutron diffractometer PLANET

Hattori, Takanori; Yagafarov, O.*; Katayama, Yoshinori; Chiba, Ayano*; Sano, Asami; Inamura, Yasuhiro; Otomo, Toshiya*; Matsuzaki, Yuki*; Shimojo, Fuyuki*

no journal, , 

PLANET is the beamline dedicated for the high-pressure experiments. The operation has been started at JFY 2013, and now many users are coming to use. In this talk, we introduce the current state of the PLANET and the example of the structure analysis of disordered materials. PLANET adopted the double staged compression system of the multi anvil 6-6, and enables the data collation at 10 GPa and 2000 K. To extend accessible PT range, we newly introduce another compression system of multi-anvil 6-8, and succeeded in generating 16 GPa and 1273 K. In addition, the PLANET is designed so that we can analyze the structure of liquid under pressure. In the analysis, the program for liquid analysis developed at BL21 NOVA is used. Here, we briefly introduce the reliability of the results and the pressure evolution of the silica glass.

Construction of high-pressure neutron diffractometer PLANET and the realization of high-pressure and high-temperature neutron experiments

Hattori, Takanori; Sano, Asami; Arima, Hiroshi*

no journal, , 

High-Pressure Neutron Diffractometer PLANET constructed at BL11 in MLF is the first neutron spectrometer dedicated to high-pressure and high-temperature (high-PT) experiments. This aims at revealing the effects of water on the physical properties of the Earth. The beamline is equipped with the multi-anvil press "ATSUHIME" that can generate high-PT condition very stably, and is able to conduct high-PT neutron experiments at 16 GPa and 1000C. The most characteristic feature of the beamline is, beside the above high-PT generation capability, that we can obtain very clean diffraction patterns with no Bragg peaks from sample surroundings, such as a heater and anvils. These characters enable us to analyze the structure not only of crystals, but also of liquids and amorphous solids. In this talk, I will introduce the performance of the spectrometer, recent results and future plan of the PLANET, together with the history of the construction.

Recent developments of high-pressure neutron experiments in J-PARC

Hattori, Takanori; Sano, Asami; Machida, Shinichi*; Arima, Hiroshi*; Abe, Jun*; Funakoshi, Kenichi*; Nakamura, Mitsutaka; Iida, Kazuki*; Kawamura, Seiko

no journal, , 

So far, high-pressure experiments using neutrons were limited due to the incompatible nature of limited neutron flux with tiny high-pressure sample. Intense neutron source of J-PARC is about to change the situation. In this talk, I will introduce the high-pressure diffraction beamline PLANET and recent results. And also, I will show you resent challenges to expand high-pressure activity to other experimental techniques, such as small angles scattering, quasi elastic scattering, and inelastic scattering.

Recent developments and current status of high-pressure neutron diffractometer PLANET in J-PARC

Hattori, Takanori; Sano, Asami; Machida, Shinichi*; Abe, Jun*; Funakoshi, Kenichi*; Arima, Hiroshi*

no journal, , 

The first domestic high-pressure powder neutron diffractometer PLANET celebrated five years since its operation started. Here, we will introduce the current status and subsequent progress. Expansion of measurable PT region: In the experiments using a 6-axis press, in-situ observation at 14 GPa, 1800 K became possible by increasing the anvil strength by shrink fitting and replacing a graphite with a TiC + AlO heater. In experiments using the Paris Edinburgh Press (PE press), by reducing the anvil top to 2.5 mm in diameter, experiments at 30 GPa are possible. Improvement of measurement data quality: when using a PE press, samples are normally pressurized together with liquid pressure medium to avoid peak broadening. However, above 10 GPa, the medium solidifies and the peaks are broadened. To fix this problem, a system capable of heating the sample up to 100C was designed and now we can obtain sharp diffraction peaks up to 20 GPa. New measurement method: In order to obtain macroscale information of samples under high PT condition, we attempted neutron radiograph. By using a compact neutron camera, we can place a camera close to the sample and obtain high resolution images.

Frontline of high-pressure neutron experiments

Hattori, Takanori

no journal, , 

So far, high-pressure experiments using neutrons were limited due to the incompatible nature of limited neutron flux with tiny high-pressure sample. Intense neutron source of J-PARC is about to change the situation. In this talk, I will introduce the high-pressure diffraction beamline PLANET and recent results. And also, I will show you resent challenges to expand high-pressure activity to other experimental techniques, such as small angles scattering, quasi elastic scattering, and inelastic scattering.