Amphiphilic Guest Sorption of K2[Cr3O(OOCC2H5)6(H2O)3]2[α-SiW12O40] Ionic Crystal
Amphiphilic Guest Sorption of K2[Cr3O(OOCC2H5)6(H2O)3]2[α-SiW12O40] Ionic Crystal
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DOI：
10.1021/ja042333s
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发表时间：
2005-07
影响因子：
15
通讯作者：
Ryosuke Kawamoto;S. Uchida;N. Mizuno
中科院分区：
文献类型：
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作者：
Ryosuke Kawamoto;S. Uchida;N. Mizuno
通过Keggin型聚氧乙烯酸盐[α-SiW_（12）O_（40）]~（4-）与K+和大阳离子[Cr_3 O（OOCC_2 H_5）_6（H_2 O）_3]~+的络合反应，合成了离子晶体K_2 [Cr_3 O（OOCC_2 H_5）_6（H_2 O）_3]_2[α-SiW_（12）O_（40）]·3 H_2 O（1a）。化合物1a在晶格中具有亲水和疏水通道。1a中的3 mol mol-1结晶水存在于亲水通道中。通过在303 K下抽真空除去结晶水以形成晶格长度变化小（±0.2 A）的无客体相1b。水吸附曲线由单一速率常数再现。因此，吸附的水可能存在于亲水通道中。化合物1b吸附各种极性有机分子，且≤C3醇的量与水相当或大于水的量，而不包括没有氢键能力的氯烃和非极性分子。因此，1b显示出两亲性吸附性质。吸附在1b中的极性有机分子的状态已被确定。
An ionic crystal K2[Cr3O(OOCC2H5)6(H2O)3]2[α-SiW12O40]·3H2O (1a) is synthesized by the complexation of a Keggin-type polyoxometalate of [α-SiW12O40]4- with K+ and a macrocation of [Cr3O(OOCC2H5)6(H2O)3]+. Compound 1a possesses both hydrophilic and hydrophobic channels in the crystal lattice. The 3 mol mol-1 of the water of crystallization in 1a resides in the hydrophilic channel. The water of crystallization is removed by the evacuation at 303 K to form the guest-free phase 1b with small changes in the lattice lengths (±0.2 A). The water sorption profile is reproduced by the single rate constant. Therefore, the water sorbed probably resides in the hydrophilic channel. Compound 1b sorbs various kinds of polar organic molecules, and the amounts of ≤C3 alcohols are comparable to or larger than that of water, while chlorocarbons with no hydrogen-bonding ability and nonpolar molecules are excluded. Thus, 1b showed the amphiphilic sorption property. The states of the polar organic molecules sorbed in 1b have be...