Cooperative Effect of Unsheltered Amide Groups on CO2 Adsorption Inside Open-Ended Channels of a Zinc(II)-Organic Framework
Cooperative Effect of Unsheltered Amide Groups on CO2 Adsorption Inside Open-Ended Channels of a Zinc(II)-Organic Framework
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DOI：
10.1021/ic302758g
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发表时间：
2013-04-01
影响因子：
4.6
通讯作者：
Lu, Kuang-Lieh
中科院分区：
文献类型：
--
作者：
Lee, Cheng-Hua;Huang, Hung-Yu;Lu, Kuang-Lieh
在锌（II）有机骨架{[Zn-4（BDC）（4）（BPDA）（4）]center dot 5DMF center dot 3 H（2）O}（n）（1，BDC = 1，4-二羧酸苄酯，BPDA = N，N '-双（4-吡啶基）-1，4-苯二甲酰胺）的开口孔道中发现了一种独特的酰胺基团空间排列方式。化合物1由4（4）-sql [Zn-4（BDC）（4）]片层组成，所述4（4）-sql [Zn-4（BDC）（4）]片层被BPDA的长连接体进一步柱撑，并形成具有α-Po 4（12）.6（3）拓扑结构的3D多孔骨架。值得注意的是，在1中的未遮蔽的酰胺基团提供了一个积极的合作效应的CO2分子的吸附，如所示的显着增加的CO2吸附焓与增加CO2的吸收。在环境条件下，观察到活性酰胺位点与CO2分子的比例为1：1。此外，化合物1比N-2更有利于CO2的捕获。DFT计算为有趣的酰胺吸附位点与CO2分子的1：1比率提供了理论基础，并揭示了化合物1的纳米室允许CO2分子的滑动平行排列，这种排列在晶体和气相CO2二聚体中发现。
A unique spatial arrangement of amide groups for CO2 adsorption is found in the open-ended channels of a zinc(II) organic framework {[Zn-4(BDC)(4)(BPDA)(4)]center dot 5DMF center dot 3H(2)O}(n) (1, BDC = 1,4-benzyl dicarboxylate, BPDA = N,N'-bis(4-pyridinyl)-1,4-benzenedi-carboxamide). Compound 1 consists of 4(4)-sql [Zn-4(BDC)(4)] sheets that are further pillared by a long linker of BPDA and forms a 3D porous framework with an alpha-Po 4(12).6(3) topology. Remarkably, the unsheltered amide groups in 1 provide a positive cooperative effect on the adsorption of CO2 molecules, as shown by the significant increase in the CO2 adsorption enthalpy with increasing CO2 uptake. At ambient condition, a 1:1 ratio of active amide sites to CO2 molecules was observed. In addition, compound 1 favors capture of CO2 over N-2. DFT calculations provided rationale for the intriguing 1:1 ratio of amide sorption sites to CO2 molecules and revealed that the nanochamber of compound 1 permits the slipped-parallel arrangement of CO2 molecules, an arrangement found in crystal and gas-phase CO2 dimer.