Cooperative Effect of Unsheltered Amide Groups on CO2 Adsorption Inside Open-Ended Channels of a Zinc(II)鈥揙rganic Framework

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• 作者：Cheng-Hua Lee ; Hung-Yu Huang ; Yen-Hsiang Liu ; Tzuoo-Tsair Luo ; Gene-Hsiang Lee ; Shie-Ming Peng ; Jyh-Chiang Jiang ; Ito Chao ; Kuang-Lieh Lu
• 刊名：Inorganic Chemistry
• 出版年：2013
• 出版时间：April 1, 2013
• 年：2013
• 卷：52
• 期：7
• 页码：3962-3968
• 全文大小：417K
• 年卷期：v.52,no.7(April 1, 2013)
• ISSN：1520-510X

文摘

A unique spatial arrangement of amide groups for CO₂ adsorption is found in the open-ended channels of a zinc(II)鈥搊rganic framework {[Zn₄(BDC)₄(BPDA)₄]路5DMF路3H₂O}_n (1, BDC = 1,4-benzyl dicarboxylate, BPDA = N,N鈥?/i>-bis(4-pyridinyl)-1,4-benzenedicarboxamide). Compound 1 consists of 4⁴-sql [Zn₄(BDC)₄] sheets that are further pillared by a long linker of BPDA and forms a 3D porous framework with an 伪-Po 4¹²路6³ 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 N₂. 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.