Postsynthetic Defect Formation in Three-Dimensional Hofmann-Type Coordination Polymers and Its Impact on Catalytic Activity
Postsynthetic Defect Formation in Three-Dimensional Hofmann-Type Coordination Polymers and Its Impact on Catalytic Activity
复制标题
三维霍夫曼型配位聚合物合成后缺陷的形成及其对催化活性的影响
DOI：
10.1021/acs.inorgchem.1c03560
复制
发表时间：
2022
影响因子：
4.6
通讯作者：
Kazutaka Sonobe
中科院分区：
文献类型：
--
作者：
Daiki Umeyama;Atsuro Takai;Kazutaka Sonobe
本文系统地研究了Hofmann型配位聚合物M（pz）[M′（CN）4]（M = Fe ~（2+），Co ~（2+），Ni ~（2+）; M′ = Pd ~（2+），Pt ~（2+）; pz =吡嗪）合成后缺陷的形成.当在环境温度下浸入甲醇（MeOH）中时，这些化合物容易在吡嗪位点进行选择性配体交换。配体交换将化学式改变为M（pz）1-x（MeOH）2x[M′（CN）4]（0 <x< 0.3），在M离子周围提供了有缺陷的配位环境。缺陷浓度高度依赖于金属离子和溶剂种类的组合，达到约0.05的缺陷浓度。最大30%（x ≤ 0.3）。一种这样的配位聚合物的磁性状态提供了对缺陷形成的额外控制，使得化合物在低自旋状态下对配体交换不太敏感。形成高浓度缺陷的结构作为催化剂起作用，并通过提供刘易斯酸性位点非均相地促进缩醛化反应。缺陷形成的溶剂依赖性特征可用于控制活性化合物的催化活性，证明了用于官能化固体材料的容易的缺陷工程。
We report a systematic investigation of postsynthetic defect formation in Hofmann-type coordination polymers M(pz)[M′(CN)4] (M = Fe2+, Co2+, Ni2+; M′ = Pd2+, Pt2+; pz = pyrazine). These compounds readily undergo selective ligand exchange at the pyrazine site when immersed in methanol (MeOH) at ambient temperature. The ligand exchange changes the chemical formula to M(pz)1–x(MeOH)2x[M′(CN)4] (0 <x< 0.3), affording a defective coordination environment around the M ions. The defect concentration is highly dependent on the combination of the metal ions and solvent species, reaching the defect concentration of ca. 30% (x∼ 0.3) at maximum. The magnetic state of one such coordination polymer gives an additional control of the defect formation, making the compound less susceptible to the ligand exchange at the low-spin state. Structures that form the defects at a high concentration function as catalysts and promote an acetalization reaction heterogeneously by providing Lewis acidic sites. The solvent-dependent character of the defect formation can be used to control the catalytic activity of the active compounds, demonstrating a facile defect engineering for functionalizing solid materials.