Takamizawa Satoshi, Kohbara Masa-aki, Miyake Ryosuke
International Graduate School of Arts and Sciences, Yokohama City University, 22-2 Seto; Kanazawa-ku, Yokohama 236-0027, Japan.
Chem Asian J. 2009 Apr 6;4(4):530-9. doi: 10.1002/asia.200800435.
To develop the application of the adsorption ability of our flexible single-crystal host Cu(2)(bza)(4)(pyz) (1) (bza = benzoate; pyz =pyrazine) possessing a 1D channel, we study the separation ability of a 1 packed column for various organic vapors and inorganic gases. A 1 packed column can detect various organic molecules with sharp signals although steric or nonpolar molecules give broad signals. Interestingly, 1 separates various organic mixtures even if the mixture contains nonpolar molecules. Comparing the separation properties with columns of other separation media, including zeolite, activated carbon, activated alumina, and silica gel, suggests that a 1 packed column separates various gaseous molecules under moderate conditions. Additionally, the eluted order of similar molecules, such as N(2)/O(2) and methanol/ethanol using the 1 packed column is different from the others (zeolite, activated carbon, activated alumina, and silica gel), which suggests a difference in the separation mechanism of 1. From GC measurements, the estimated changes in Gibbs free energy by gas adsorption, under diluted gas conditions, exhibits a large entropy dependence caused by regularity in the generated adsorption state, which enables the dynamic control of gas adsorption selectivity. Therefore, it is suggested that single-crystal host 1, because of its flexibility, can separate various gases by adjusting its channel structure according to the features of the guest gaseous molecules. This generates active controllability of the adsorption potential in addition to the intrinsic adsorption interaction.
为了开发具有一维通道的柔性单晶主体Cu(2)(bza)(4)(pyz) (1)（bza = 苯甲酸根；pyz = 吡嗪）的吸附能力的应用，我们研究了填充有1的柱对各种有机蒸气和无机气体的分离能力。填充有1的柱可以检测各种有机分子，并给出尖锐的信号，尽管空间位阻或非极性分子会给出宽泛的信号。有趣的是，1即使在混合物中含有非极性分子的情况下也能分离各种有机混合物。将其与包括沸石、活性炭、活性氧化铝和硅胶在内的其他分离介质的柱的分离性能进行比较表明，填充有1的柱在温和条件下能分离各种气态分子。此外，使用填充有1的柱时，类似分子如N(2)/O(2)和甲醇/乙醇的洗脱顺序与其他柱（沸石、活性炭、活性氧化铝和硅胶）不同，这表明1的分离机制存在差异。通过气相色谱测量，在稀释气体条件下，气体吸附引起的吉布斯自由能的估计变化表现出由生成的吸附状态的规律性引起的大的熵依赖性，这使得能够动态控制气体吸附选择性。因此，有人认为单晶主体1由于其柔性，可以根据客体气态分子的特征调整其通道结构来分离各种气体。除了固有的吸附相互作用外，这还产生了吸附势的主动可控性。
