A Homochiral Metal–Organic Material with Permanent Porosity, Enantioselective Sorption Properties, and Catalytic Activity

Abstract

Metal-organic porous materials are receiving growing attention [1] because of their potential applications in gas storage, [2] separation, [3] and many other areas. [4] Although catalysis is one of the most promising applications of such materials, only a handful of examples have been reported to date. [5] Furthermore, despite considerable efforts, attempts to synthesize robust, homochiral metal-organic porous materials capable of enantioselective separation and/or catalysis have met with only limited success. [6,7] Most homochiral metalorganic frameworks are not robust enough to show permanent porosity, nor porous enough to be useful for selective sorption or catalytic transformation of organic molecules. Therefore, the synthesis of robust homochiral metal-organic frameworks with potential for application is still challenging. For the synthesis of homochiral metal-organic open frameworks, two general approaches have been taken: 1) use of a rigid homochiral organic ligand as a spacer to link adjacent metal centers or secondary building units (SBUs), [5b-d, 7] and 2) use of a homochiral ligand as an auxiliary pendant which does not directly participate in the formation of a framework backbone, but forces the framework to adopt a specific chiral topology.[3d] Herein, we introduce another rational approach to the synthesis of homochiral metal-organic frameworks. A metal ion and a readily available homochiral organic ligand are used to form homochiral SBUs, which in turn, are linked together by rigid spacers to build a network structure, in a one-pot reaction (Scheme 1).[8] With a judicious choice of metal ion, homochiral organic molecule, and rigid polytopic linker (that is, a connector with more than one metal coordination site), this approach allows us to synthesize metal-organic open frameworks with stable chiral pores. Herein, we report a new homochiral metal-organic material that has permanent porosity, size-and enantioselective sorption properties, and catalytic activity.[9]

Distinguishing Metal–Organic Frameworks

“…Two structures, JAVNIE 68 and FUSWIA, 69 differ by water coordinated to the copper atoms of the framework [Cu 3 Cl 2 (5-(4-pyridyl)tetrazolato) 4 ], which is present in JAVNIE but absent in FUSWIA, as well as by the clathrate molecules dimethylformamide and methanol in FUSWIA and dimethylformamide and water in JAVNIE. More examples of duplicates caused by different solvent molecules are the pairs AMIMEP 41 and AMILUE, 41 and HEGJUZ 42 and XUVHEB, 43 which are discussed in Methods ( Figures 3 and 4 ), SAKRED 70 and SEFBOV, 71 and KAXQOR 64 and ZERQOE 63 ( Figure 7 a,b). However, the pair GOMRAC 72 and GOMREG 72 of AlPO 4 is a duplicate due to neglect of the metal disorder ( Figure 7 c).…”

Chemical Reactions at Isolated Single-Sites Inside Metal–Organic Frameworks

“…Copyright 2016 Springer Nature post-synthetic modification of homochiral MOFs, or incorporation of asymmetric catalysts directly into the framework [154][155][156][157][158][159][160]. The substantial potential of homochiral MOFs in enantioselective asymmetric catalytic reactions has been discussed by a number of different groups [25,155,[161][162][163][164][165][166]. Tremendous efforts have been dedicated to homochiral MOF powder materials.…”

A Family of Nanoporous Materials Based on an Amino Acid Backbone

“…Extended frameworks based on metal aspartates have recently been reported;2 however, the structural motifs in these frameworks are too dense to generate guest‐accessible volume. The lactate7 and tartrate8 anions have also been used in the construction of metal–organic frameworks.…”