Takamizawa Satoshi, Nakata Ei-Ichi, Akatsuka Takamasa, Kachi-Terajima Chihiro, Miyake Ryosuke
International Graduate School of Arts and Sciences, Yokohama City University, 22-2 Seto, Kanazawa-ku, Yokohama 236-0027, Japan.
J Am Chem Soc. 2008 Dec 31;130(52):17882-92. doi: 10.1021/ja806257m.
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) (bza = benzoate; pyz = pyrazine; M = Rh(II) (1a) and Cu(II) (1b)) and M(2)(bza)(4)(2-mpyz) (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.
我们报道了 O₂ 分子在四种类型的单晶吸附剂通道中的磁行为，这四种吸附剂为 [M₂(bza)₄(pyz)]ₙ（bza = 苯甲酸根；pyz = 吡嗪；M = Rh(II) (1a) 和 Cu(II) (1b)）以及 [M₂(bza)₄(2 - mpyz)]ₙ（2 - mpyz = 2 - 甲基吡嗪；M = Rh(II) (2a) 和 Cu(II) (2b)）。测定了 1a 和 2a 的含 O₂ 晶体在 10 至 298 K 不同温度下的 X 射线单晶结构。所有吸附的 O₂ 分子在 55 - 105 K 左右的温度范围内，在高于 4 T 的磁场中呈现出异常磁相。讨论了四种包合物中吸附的 O₂ 分子的磁行为。通过对磁化时间过程的分析揭示了亚稳态的存在，M - H 曲线上的磁滞现象也表明了这一点。考虑到异常磁行为发生在相对较高的温度和较低的磁场下，推测这些行为是由于所包含的 O₂ 聚集体的磁相互作用发生变化而引起的，这种变化涉及转变，且在施加磁场下单晶主体通道的环境对此起到了支持作用。
