Ligand-Directed and pH-Controlled Assembly of Chiral 3d−3d Heterometallic Metal−Organic Frameworks

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• 作者：Zhi Su ; Jian Fan ; Taka-aki Okamura ; Wei-Yin Sun ; Norikazu Ueyama
• 刊名：Crystal Growth & Design
• 出版年：2010
• 出版时间：August 4, 2010
• 年：2010
• 卷：10
• 期：8
• 页码：3515-3521
• 全文大小：1010K
• 年卷期：v.10,no.8(August 4, 2010)
• ISSN：1528-7505

文摘

Use of unsymmetric ligand 1,2,4-benzenetricarboxylic acid (1,2,4-H₃BTC) and controlling the reaction pH value enabled isolation of two novel chiral 3d-3d heterometallic complexes [Zn₂Co(tib)₃(H₂O)₅][Zn₆(tib)₂(1,2,4-BTC)₆]·12.7H₂O (1) and [ZnCo(tib)(1,2,4-BTC)(H₂O)₂]Cl·3H₂O (2) [tib =1,3,5-tris(1-imidazolyl)benzene]. Comparative study revealed that the use of symmetric ligand 1,3,5-benzenetricarboxylic acid (1,3,5-H₃BTC) resulted one achiral 3d-3d heterometallic complex [ZnCo(tib)(1,3,5-BTC)Cl] (3) with 3D structure. Complex 1 is a 2D network with cationic and anionic layers arranged alternately, while 2 is a 3D framework with rare 1D helical water chains. Furthermore, complex 1 displays ferroelectric behavior with a remnant electric polarization (P_r) of 0.177 μC/cm² and an electric coercive field (E_c) of 17.68 kV/cm.