Functionalization of Microporous Lanthanide-Based Metal–Organic Frameworks by Dicarboxylate Ligands with Methyl-Substituted Thieno[2,3-b]thiophene Groups: Sensing Activities and Magnetic Properties

详细信息    查看全文

• 作者：Suna Wang ; Tingting Cao ; Hui Yan ; Yunwu Li ; Jing Lu ; Ranran Ma ; Dacheng Li ; Jianmin Dou ; Junfeng Bai
• 刊名：Inorganic Chemistry
• 出版年：2016
• 出版时间：June 6, 2016
• 年：2016
• 卷：55
• 期：11
• 页码：5139-5151
• 全文大小：987K
• 年卷期：0
• ISSN：1520-510X

文摘

From a methyl-substituted thieno[2,3-b]thiophene dicarboxylate, three types of three-dimensional (3-D) microporous lanthanide-based metal–organic frameworks, {[Ln(DMTDC)_1.5(H₂O)₂]·DEF}_n (type I, Ln = Eu 1, Tb 2), {[Ln(DMTDC)_1.5(H₂O)₂]·0.5DMF·0.5H₂O}_n (type II, Ln = Gd 3, Dy 4, Er 5), and {[Ln₄(DMTDC)₆(DMF)₂]·0.5DMF·1.5H₂O}_n (type III, Ln = Er 6) (H₂DMTDC = 3,4-dimethylthieno[2,3-b]thiophene-2,5-dicarboxylic acid, DEF = N,N′-diethylformamide, DMF = N,N′-dimethylformamide), have been solventhermally synthesized. Types I and II are isostructural, which exhibit 1-D triangular channels constructed by double-stranded rod-shaped {Ln(CO₂)₂}_n chains. Type III demonstrates an intriguing framework with triple-stranded rod-shaped {Ln(CO₂)₃}_n chains arranged along the (1,1,0) and (1,–1,0) axes and possesses two kinds of triangular channels along two axes, respectively. Immobilization of the Lewis basic sites of thiophene groups induced gas adsorption and sensing properties into these microporous frameworks. Complexes 5(Er) and 6(Er) display moderate adsorption properties toward N₂ and CO₂, and the Q_st of CO₂ are as high as 36.3 and 34.8 kJ mol^–1, respectively. Complexes 1(Eu) and 2(Tb) exhibit sensing properties toward nitrobenzene, acetone, and the Cu²⁺ ion in both DMF and aqueous solution. Complex 3(Gd) shows a significant magnetocaloric effect with ΔS_m = 24.3 J·kg^–1·K^–1 at 3.0 K and 7 T. Complex 4(Dy) exhibits slow magnetic relaxation with the energy barrier Δ/k_B of 48.29 K.