Takamasa Akatsuka

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.

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.

Switch of channel geometry by 1D component slide responding to slight structural stimuli of adsorbed guest

The adsorption behavior of a flexible single-crystal host [Cu2(bza)4(pyz)]n was studied for a planar triangular molecule and investigated for large host structural changes including a switch of channel geometry responding to included guest molecules.

Gas-adsorbing ability of tris-ethylenediamine metal complexes (M = Co(III), Cr(III), Rh(III), Ir(III)) as transformable ionic single crystal hosts

We previously reported that a single crystal of [Co(en)3]Cl3 shows gas adsorbency for various gases and organic vapors accompanying channel expansion in its crystal structure. To investigate the possibility of a single crystal of tris-ethylenediamine metal complex as an ionic single-crystal host for vapor adsorption, a series of adsorbencies of single crystals of [MIII(en)3]Cl3 (M = Co 1, Cr 2, Rh 3, Ir 4) were studied. All complexes have channels in their crystal structures, which dynamically and reversibly change size with vapor adsorption and show similar vapor adsorbency similar to the adsorption behavior of [Co(en)3]Cl3.