Patra Rajesh, Mondal Sumit, Sarma Debajit
Department of Chemistry, Indian Institute of Technology Patna, Bihar 801106, India.
Dalton Trans. 2023 Dec 5;52(47):17623-17655. doi: 10.1039/d3dt02884d.
Metal-organic frameworks (MOFs) are unique hybrid porous materials formed by combining metal ions or clusters with organic ligands. Thiol and thioether-based MOFs belong to a specific category of MOFs where one or many thiols or thioether groups are present in organic linkers. Depending on the linkers, thiol-thioether MOFs can be divided into three categories: (i) MOFs where both thiol or thioether groups are part of the carboxylic acid ligands, (ii) MOFs where only thiol or thioether groups are present in the organic linker, and (iii) MOFs where both thiol or thioether groups are part of azolate-containing linkers. MOFs containing thiol-thioether-based acid ligands are synthesized through two primary approaches; one is by utilizing thiol and thioether-based carboxylic acid ligands where the bonding pattern of ligands with metal ions plays a vital role in MOF formation (HSAB principle). MOFs synthesized by this approach can be structurally differentiated into two categories: structures without common structural motifs and structures with common structural motifs (related to UiO-66, UiO-67, UiO-68, MIL-53, NU-1100, .). The second approach to synthesize thiol and thioether-based MOFs is indirect methods, where thiol or thioether functionality is introduced in MOFs by techniques like post-synthetic modifications (PSM), post-synthetic exchange (PSE) and by forming composite materials. Generally, MOFs containing only thiol-thioether-based ligands are synthesized by interfacial assisted synthesis, forming two-dimensional sheet frameworks, and show significantly high conductivity. A limited study has been done on MOFs containing thiol-thioether-based azolate ligands where both nitrogen- and sulfur-containing functionality are present in the MOF frameworks. These materials exhibit intriguing properties stemming from the interplay between metal centres, organic ligands, and sulfur functionality. As a result, they offer great potential for multifaceted applications, ranging from catalysis, sensing, and conductivity, to adsorption. This perspective is organised through an introduction, schematic representations, and tabular data of the reported thiol and thioether MOFs and concluded with future directions.
金属有机框架材料（MOFs）是由金属离子或簇与有机配体结合形成的独特的杂化多孔材料。基于硫醇和硫醚的MOFs属于MOFs的一个特定类别，其中有机连接体中存在一个或多个硫醇或硫醚基团。根据连接体的不同，硫醇-硫醚MOFs可分为三类：（i）硫醇或硫醚基团均为羧酸配体一部分的MOFs；（ii）有机连接体中仅存在硫醇或硫醚基团的MOFs；（iii）硫醇或硫醚基团均为含氮唑连接体一部分的MOFs。含有基于硫醇-硫醚的酸性配体的MOFs通过两种主要方法合成；一种是利用基于硫醇和硫醚的羧酸配体，其中配体与金属离子的键合模式在MOF形成中起着至关重要的作用（软硬酸碱原理）。通过这种方法合成的MOFs在结构上可分为两类：没有共同结构基序的结构和具有共同结构基序的结构（与UiO-66、UiO-67、UiO-68、MIL-53、NU-1100等相关）。合成基于硫醇和硫醚的MOFs的第二种方法是间接方法，即通过后合成修饰（PSM）、后合成交换（PSE）等技术以及形成复合材料在MOFs中引入硫醇或硫醚官能团。一般来说，仅含有基于硫醇-硫醚的配体的MOFs通过界面辅助合成法合成，形成二维片状框架，并显示出显著的高导电性。对含有基于硫醇-硫醚的含氮唑配体的MOFs的研究有限，其中MOF框架中同时存在含氮和含硫官能团。这些材料由于金属中心、有机配体和硫官能团之间的相互作用而表现出有趣的性质。因此，它们在催化、传感、导电和吸附等多方面应用中具有巨大潜力。本文通过对已报道的硫醇和硫醚MOFs的介绍、示意图和表格数据进行组织，并以未来方向作为结论。
