Metal-organic solids derived from arylphosphonic acids

Abstract

Metal-organophosphonates can be a superior alternative to the widely-explored carboxylate based metal organic frameworks (MOFs) as they exhibit better heat resistance and air sensitivity. However, due to the highly diverse binding modes of the metal-organophosphonate compounds and limited number of arylphosphonate linkers, it has been a very difficult task to create predictable extended and porous frameworks in this system. In 80s, 90s and 2000s, the literature of metal-organophosphonate chemistry were dominated by aliphatic linkers and highly dense pillared layered structures. Only recently rigid and structurally directing aromatic organophosphonates have been synthesized and employed to create porous frameworks. With metal-arylphosphonate chemistry still being an emerging field there is an urgent need to provide an overview of published arylphosphonates, their metal complexes and properties. Herein, we summarize the known metal-arylphosphonates based on their geometrical structures and number of phosphonate linkers around the aryl scaffold. The first part of the review summarizes the linear ditopic arylphosphonate linkers, the second part summarizes the trigonal planar geometries and the effect of opening the distance between the phosphonate linkers on the porosity. The third chapter focuses on tetratopic organophosphonate linkers with two-dimensional square planar geometries and geometries opening to three-dimensions. In the final chapter, miscellaneous multitopic organophosphonate linkers are presented. The review article not only summarizes arylphosphonic acids but also the their related arylphosphonate monoesters and diesters. In addition to structural chemistry, each of the chapters presented in the review article also summarize catalytic, sorptive and proton conductivity properties of published metal organophosphonates. (C) 2018 Elsevier B.V. All rights reserved.