Ei-ichi Nakata

Synthesis of novel copper (II) benzoate pyrazine and its phase transition induced by CO 2 adsorption

Abstract A novel crystalline solid, [Cu(II)2(O2CPh)4(pyz)]n, was synthesized and characterized by single-crystal X-ray diffraction analysis; the compound demonstrates thermal phase transition that is correlated with CO2 adsorption.

Structural and Magnetic Study of O2 Molecules Arranged along a Channel in a Flexible Single-Crystal Host Family

We report the magnetic behaviors of O(2) molecules, which aligned in the channels of four types of single-crystal adsorbents, [M(2)(bza)(4)(pyz)](n) (bza = benzoate; pyz = pyrazine; M = Rh(II) (1a) and Cu(II) (1b)) and [M(2)(bza)(4)(2-mpyz)](n) (2-mpyz = 2-methylpyrazine; M = Rh(II) (2a) and Cu(II) (2b)). The X-ray single-crystal structures at various temperatures from 10 to 298 K were determined for O(2)-included crystals of 1a and 2a. All adsorbed O(2) molecules exhibited abnormal magnetic phases above 4 T in the temperature range around 55-105 K. The magnetic behaviors of adsorbed O(2) molecules between four inclusions were discussed. The existence of the metastable state, which was also suggested by hysteresis on the M-H curves, was revealed by analysis of the time course of the magnetization. Considering that the abnormal magnetic behavior occurred at relatively high temperatures and a low magnetic field, it was suggested that these behaviors were induced because of the changes of magnetic interaction of included O(2) aggregates involving transformation which is supported by the surrounding of the channels of the single-crystal hosts under the applied magnetic field.

Direct observation of H2 adsorbed state within a porous crystal by single crystal X-ray diffraction analysis

The crystal structure of a porous single crystal under a state of hydrogen gas adsorption equilibrium at 90 K revealed an aggregated hydrogen dimer packed in narrow portions in the pore.

Structural determination of physisorbed sites for CO2 and Ar gases inside an organometallic framework

The crystal structures of two gas inclusion compounds containing carbon dioxide and argon have been determined by conventional single-crystal X-ray diffraction analysis at room temperature. The analysis revealed different manners of gas inclusion, where hydrogen bond interaction and the π orbital of the conjugate plane cooperatively capture the adsorbed gaseous guests.

Construction of oxygen inclusion solid using copper(II) benzoate–pyrazine

The generation of oxygen inclusion crystals through oxygen gas adsorption was characterized at 90 K to show that a one-dimensional oxygen molecular chain crystallizes in the channels of the host lattice to be captured with its exact structure stabilized under the included state.

Structural determination of a 1-D metal–organic framework with adsorbed oxygen molecules at 10 K: possibility of surface motion transfer of confined guest

Single-crystal X-ray analysis at 10 K revealed adsorbed oxygen within the ultramicropores of a single crystal gas adsorbent, rhodium(II) benzoate-pyrazine. This indicates that the oxygen molecules were captured on the necks of infinite channels by the intermolecular interaction between the guest O2 and the benzoate moieties on the inner host surface and the guest probably diffuses through the narrow necks driven by surface local motion.