4,4′-(Pyridine-3,5-diyl)dibenzoic acid (H₂pdba) was explored as an adaptable linker for assembling a diversity of new manganese(II), cobalt(II/III), nickel(II), and copper(II) coordination polymers (CPs): [Mn(μ₄-pdba)(H₂O)]_n (1), {[M(μ₃-pdba)(phen)]·2H₂O}_n (M = Co (2), Ni (3)), {[Cu₂(μ₃-pdba)₂(bipy)]·2H₂O}_n (4), {[Co(μ₃-pdba)(bipy)]·2H₂O}_n (5), [Co₂(μ₃-pdba)(μ-Hbiim)₂(Hbiim)]_n (6), and [M(μ₄-pdba)(py)]_n (M = Co (7), Ni (8)). The CPs were hydrothermally synthesized using metal(II) chloride precursors, H₂pdba, and different coligands functioning as crystallization mediators (phen: 1,10-phenanthroline; bipy: 2,2′-bipyridine, H₂biim: 2,2′-biimidazole; py: pyridine). Structural networks of 1–8 range from two-dimensional (2D) metal–organic layers (1–3, 5–8) to three-dimensional (3D) metal–organic framework (MOF) (4) and disclose several types of topologies: sql (in 1), hcb (in 2, 3, 5), tfk (in 4), 3,5L66 (in 6), and SP 2-periodic net (6,3)Ia (in 7, 8). Apart from the characterization by standard methods, catalytic potential of the obtained CPs was also screened in the Knoevenagel condensation of benzaldehyde with propanedinitrile to give 2-benzylidenemalononitrile (model reaction). Several reaction parameters were optimized, and the substrate scope was explored, revealing the best catalytic performance for a 3D MOF 4. This catalyst is recyclable and can lead to substituted dinitrile products in up to 99% product yields. The present study widens the use of H₂pdba as a still poorly studied linker toward designing novel functional coordination polymers.

中文翻译：

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由适应性吡啶-二羧酸连接体构建的配位聚合物：组装、结构多样性和催化

4,4'-(Pyridine-3,5-diyl)dibenzoic acid (H ₂ pdba) 被探索为组装多种新型锰 (II)、钴 (II/III)、镍 (II)、和铜(II)配位聚合物(CPs)：[Mn(μ ₄ -pdba)(H ₂ O)] _n ( 1 ), {[M(μ ₃ -pdba)(phen)]·2H ₂ O} _n ( M = Co ( 2 ), Ni ( 3 ), {[Cu ₂ (μ ₃ -pdba) ₂ (bipy)]·2H ₂ O} _n ( 4 ), {[Co(μ ₃ -pdba)(bipy) ]·2H ₂ O} _n (5 ), [Co ₂ (μ ₃ -pdba)(μ-Hbiim) ₂ (Hbiim)] _n ( 6 ), 和 [M(μ ₄ -pdba)(py)] _n (M = Co ( 7 ), Ni （8））。使用金属 (II) 氯化物前体、H ₂ pdba 和充当结晶介质的不同配体（phen：1,10-菲咯啉；bipy：2,2'-联吡啶，H ₂ biim：2,2' ）水热合成 CP -联咪唑；py：吡啶）。1 – 8的结构网络范围从二维 (2D) 金属有机层 ( 1 – 3 , 5 –8 ) 到三维 (3D) 金属有机框架 (MOF) ( 4 ) 并公开了几种类型的拓扑结构：sql (in 1 ), hcb (in 2 , 3 , 5 ), tfk (in 4 ), 3, 5L66（在6中）和 SP 2-周期性网络 (6,3)Ia（在7 , 8中). 除了通过标准方法表征外，还在苯甲醛与丙二腈的 Knoevenagel 缩合反应中筛选获得的 CP 的催化潜力，得到 2-亚苄基丙二腈（模型反应）。优化了几个反应参数，探索了底物范围，揭示了 3D MOF 4的最佳催化性能。这种催化剂是可回收的，可以产生高达 99% 的产品收率的取代二腈产品。本研究拓宽了 H ₂ pdba 作为一种研究较少的连接基的用途，用于设计新型功能性配位聚合物。