Takahashi Kiyonori, Takeda Takashi, Zheng Xin, Noro Shin-Ichiro, Akutagawa Tomoyuki, Nakamura Takayoshi
Research Institute for Electronic Science, Hokkaido University, Sapporo, Hokkaido 001-0020, Japan.
Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Sendai, Miyagi 980-8577, Japan.
Inorg Chem. 2023 Sep 18;62(37):14942-14948. doi: 10.1021/acs.inorgchem.3c01641. Epub 2023 Sep 1.
Structural changes of the coordination polymer associated with gas adsorption (gate opening-type adsorption) can be linked to bulk physical properties such as magnetism, electrical conductivity, and dielectric properties. To enable real-space sensing applications, it is imperative to have a system where the selective adsorption of mixed gases can be correlated with physical properties. In this report, we demonstrate that a crystalline sample of one-dimensional (1D) coordination polymer exhibits selective CO adsorption while simultaneously displaying dielectric switching behavior in a mixed N/CO gas environment. In the crystal of {[Cu(2-TPA)(pz)]·CHCN} (·CHCN), where 2-TPA and pz are 2-thiophencarboxylate and pyrazine, respectively, paddle wheel-type units of [Cu(2-TPA)] are bridged by pz, forming a 1D chain structure. One of the two crystallographically independent 2-TPA units was interacted with the pz moiety of the adjacent 1D chain by π···π interactions, forming a two-dimensional (2D) layer parallel to the plane. Activated shows selective CO adsorption by a gate opening-type adsorption mechanism, indicating that the CO adsorption process is accompanied by a structural change. The change in the real part of dielectric permittivity (ε') under the mixed N/CO gas flow is a result of the selective CO adsorption, which was supported by the enthalpy changes (Δ) associated with CO adsorption in two methods: CO adsorption isotherms and temperature-dependent measurements of ε' under a mixed N/CO gas flow. The calculated Δ values were found to be in good agreement across both methods. The CO ratio in the mixed N/CO gas flow increased, and the switching ratio of ε' (Δε') also increased. Notably, Δε' exhibited a marked increase beyond the pressure required for gate opening adsorption.
与气体吸附（门控型吸附）相关的配位聚合物的结构变化可与诸如磁性、电导率和介电性能等体相物理性质联系起来。为了实现实空间传感应用，必须有一个系统，其中混合气体的选择性吸附能够与物理性质相关联。在本报告中，我们证明了一维（1D）配位聚合物的晶体样品在混合N₂/CO气体环境中表现出选择性CO吸附，同时显示出介电切换行为。在{[Cu(2-TPA)(pz)]·CH₃CN}（·CH₃CN）晶体中，其中2-TPA和pz分别是2-噻吩羧酸酯和吡嗪，[Cu(2-TPA)]的桨轮型单元由pz桥连，形成一维链结构。两个晶体学独立的2-TPA单元之一通过π···π相互作用与相邻一维链的pz部分相互作用，形成平行于 平面的二维（2D）层。活化后的样品通过门控型吸附机制表现出选择性CO吸附，表明CO吸附过程伴随着结构变化。在混合N₂/CO气流下介电常数实部（ε'）的变化是选择性CO吸附的结果，这通过两种方法中与CO吸附相关的焓变（Δ）得到支持：CO吸附等温线和在混合N₂/CO气流下ε'的温度依赖性测量。发现两种方法计算得到的Δ值吻合良好。混合N₂/CO气流中CO比例增加，ε'的切换比（Δε'）也增加。值得注意的是，Δε'在门控型吸附所需压力以上表现出显著增加。
