Department of Chemistry and Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Fudan University, 220 Handan Road, Shanghai 200433, P. R. China.
Chemistry. 2011 Sep 5;17(37):10323-8. doi: 10.1002/chem.201101239. Epub 2011 Aug 4.
Three isoreticular zinc(II)-phosphonocarboxylate frameworks, namely {[Zn(3)(pbdc)(2)]·2H(3)O}(n) (ZnPC-2), {[Zn(3)(pbdc)(2)]·Hpd·H(3)O·4H(2)O}(n) (Hpd@ZnPC-2) and {[Co(1.5)Zn(1.5)(pbdc)(2)]·2H(3)O}(n) (CoZnPC-2) (H(4)pbdc=5-phosphonobenzene-1,3-dicarboxylic acid, pd=pyrrolidine), were solvothermally synthesized. ZnPC-2 has a 3D structure based on trinuclear Zn(II) clusters (Zn(3)-SBU) showing 3D interconnected channels. Hpd@ZnPC-2 contains an isoreticular framework of ZnPC-2 with small channels blocked by Hpd molecules. In CoZnPC-2, Zn(II) ions in ZnPC-2 are partially substituted by Co(II) ions. The Friedel-Crafts benzylation reactions were carried out over these isoreticular porous materials. The catalytic results reveal that ZnPC-2 is an excellent heterogeneous Lewis acid catalyst with a high selectivity (>90%) towards less bulky para-oriented products. The catalytic reaction has been proved to occur inside the pore of ZnPC-2, and the immobilized Zn(3)-SBUs are the active sites.
三种等结构的锌（II）-膦酸酯框架，即{[Zn(3)(pbdc)(2)]·2H(3)O}(n) (ZnPC-2)、{[Zn(3)(pbdc)(2)]·Hpd·H(3)O·4H(2)O}(n) (Hpd@ZnPC-2) 和 {[Co(1.5)Zn(1.5)(pbdc)(2)]·2H(3)O}(n) (CoZnPC-2) (H(4)pbdc=5-膦酸基苯-1,3-二羧酸，pd=吡咯烷)，通过溶剂热法合成。ZnPC-2 具有基于三核 Zn(II)簇（Zn(3)-SBU）的 3D 结构，呈现 3D 相互连接的通道。Hpd@ZnPC-2 包含具有小通道的 ZnPC-2 的等结构骨架，这些小通道被 Hpd 分子堵塞。在 CoZnPC-2 中，ZnPC-2 中的 Zn(II)离子部分被 Co(II)离子取代。这些等结构多孔材料进行了 Friedel-Crafts 苯甲基化反应。催化结果表明，ZnPC-2 是一种出色的非均相路易斯酸催化剂，对较小体积的对位产物具有高选择性（>90%）。催化反应已被证明在 ZnPC-2 的孔内发生，并且固定化的 Zn(3)-SBU 是活性位点。
