Ryo Kitaura

Flexible and dynamic coordination polymers based on interpenetration and interdigitation have been synthesized and characterized. Reversible crystal-to-crystal transformation from a nonporous structure (24 m2 g−1) to a microporous structure (at least 320 m2 g−1) is triggered by adsorption of various supercritical gases (see picture).

We report the direct observation of dioxygen molecules physisorbed in the nanochannels of a microporous copper coordination polymer by the MEM (maximum entropy method)/Rietveld method, using in situ high-resolution synchrotron x-ray powder diffraction measurements. The obtained MEM electron density revealed that van der Waals dimers of physisorbed O2 locate in the middle of nanochannels and form a one-dimensional ladder structure aligned to the host channel structure. The observed O-O stretching

A hysteretic adsorption and desorption profile (right) accompanied by a transformation of the crystal structure is observed for the title coordination polymer, which possesses a pillared-layer structure (left), on exposure to H2O or MeOH vapor under pressure.

Wall decoration: Coordinatively unsaturated metal centers (CuII, CoII, and NiII) can be embedded in the pore wall of a microporous coordination polymer containing Schiff base type metalloligands [M(salphdc)]2− (H4salphdc=N,N′-o-phenylenebis(salicylideneimine-5,5′-dicarboxylic acid)). These coordination polymers possess large 1D channels with dimensions of approximately 14×14 Å2 (see structure).

A new three-dimensional (3-D) jungle-gym-like open metal-organic framework has been synthesized from a two-dimensional (2-D) layer compound using a heterogeneous pillar insertion reaction. Both the starting 2-D layer and the resulting 3-D open compounds have been characterized using X-ray crystallography.

A nano-template reaction has been developed to fabricate metal nanowires using metallofullerene nanopeapods (i.e., carbon nanotubes (CNTs) encapsulating endohedral metallofullerenes) as starting materials. In this nanometer-scale reaction, the structure of resulting products should possess specific low-dimensional structures, because of their uniform starting orientation of metallofullerene molecules and the rigid restriction of reaction space by the presence of walls of CNTs. Using the nano-tem

A van der Waals (vdW) heterostructure composed of multivalley systems can show excitonic optical responses from interlayer excitons that originate from several valleys in the electronic structure. In this work, we studied photoluminescence (PL) from a vdW heterostructure, WS₂/MoS₂, deposited on hexagonal boron nitride (hBN) flakes. PL spectra from the fabricated heterostructures observed at room temperature show PL peaks at 1.3-1.7 eV, which are absent in the PL spectra of

Progress on researches of two-dimensional (2D) metals strongly relies on development of the growth technique. Studies on preparation of 2D metals have so far been limited, and this is in stark contrast to the situation of 2D semiconductors, where various layered semiconductors, including MoS2, WS2, MoSe2, WSe2, have been isolated in its monolayer form. In this work, we have developed a facile method to prepare 2D metallic transition metal dichalcogenides (TMDCs) by chemical vapor deposition (CVD

Filling the tube: Ultrathin metal nanowires with diameters of single atoms (ca. 1.7 nm) were synthesized in high yield by using a nanofilling reaction using the nanospace of carbon nanotubes (CNTs). As the nanowires are protected by the wall of the CNTs, they resist oxidation and structural disintegration even under ambient conditions.

Ein hystereseförmiges Adsorptions-/Desorptionsprofil (rechts) und die Umwandlung der Kristallstruktur bei Einwirkung von H2O- oder MeOH-Dampf unter Druck wird bei der Titelverbindung beobachtet, die aus übereinander gestapelten Säulen aufgebaut ist (links).

Molecules and atoms confined in a nanospace may have properties distinctly different from those of the bulk fluid, owing to the formation of a specific molecular array characteristic of nanospace. In situ synchrotron powder X-ray diffraction measurements have been used to observe confined guest molecules such as N2, O2, Ar, and CH4 in the well-regulated ultramicropore of a copper coordination polymer, 1 ([Cu2(pzdc)2pyz]: pzdc = 2,3-pyrazinedicarboxylate and pyz = pyrazine). The obtained crystal

We have developed a facile and general method to passivate thin black phosphorus (BP) flakes with large-area high-quality monolayer hexagonal boron nitride (hBN) sheets grown by the chemical vapor deposition (CVD) method. In spite of the one-atom-thick structure, the high-quality CVD-grown monolayer hBN has proven to be useful to prevent the degradation of thin BP flakes exfoliated on substrates. Mechanically exfoliated BP flakes prepared on a Si substrate are covered by the monolayer hBN sheet

This review article focuses on the structures and properties of novel hybrid nanocarbon materials, which are created by incorporating atoms and molecules into the hollow spaces of carbon nanotubes (CNTs); thus they are called nanopeapods. After dealing with synthesis procedures, we discuss the structures and electronic properties of the hybrid materials based on high-resolution transmission electron microscopy (HRTEM), electron energy-loss spectroscopy (EELS), X-ray and electron diffraction, sca

Crystalline ErCl3 nanowires have been fabricated in single-walled carbon nanotubes (SWCNTs) with high yield (∼90%), and the structural and magnetic properties of the resulting ErCl3 nanowires encapsulated in SWCNTs (ErCl3@SWCNTs) characterized. Encapsulation under high temperature and vacuum using high quality SWCNTs results in a high filling-ratio of ErCl3 nanowires in the SWCNTs. The high filling-ratio of ErCl3 nanowires and the use of highly pure SWCNTs with only a small amount of residual Fe