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Metal–Organic Frameworks and Self-Assembled Supramolecular Coordination Complexes: Comparing and Contrasting the Design, Synthesis, and Functionality of Metal–Organic Materials

Applications of Supramolecular Anion Recognition

The application of metal-organic frameworks (MOFs) to anion separations with a special emphasis on anion selectivity is reviewed. The coordination frameworks are classified on the basis of the main interactions to the included anion, from weak and non-specific van der Waals forces to more specific interactions such as coordination to Lewis acid metal centers or hydrogen bonding. The importance of anion solvation phenomena to the observed anion selectivities is highlighted, and strategies for reversing the Hofmeister bias that favors large, less hydrophilic anions, and for obtaining peak selectivities based on shape recognition are delineated. Functionalization of the anion-binding sites in MOFs with strong and directional hydrogen-bonding groups that are complementary to the included anion, combined with organizational rigidity of the coordination framework, appears to be the most promising approach for achieving non-Hofmeister selectivity.

Anion Separation with Metal–Organic Frameworks

Dichromate capture: A 3D cationic metal-organic framework consisting of distorted octahedral and tetrahedral cages was constructed by using Ag(I) and 4,4'-bis(1,2,4-triazole). The complex exhibits fast exchange, high trapping capacity, and good selectivity for Cr2 O7 (2-) through single-crystal to single-crystal transformation. The complex also features a bluish violet luminescence that is distinctly quenched after Cr2 O7 (2-) exchange.

A Cationic Metal–Organic Framework Consisting of Nanoscale Cages: Capture, Separation, and Luminescent Probing of Cr2O72− through a Single‐Crystal to Single‐Crystal Process

Ionic metal-organic frameworks (iMOFs): Design principles and applications

Six noninterpenetrating or- ganic ± inorganic hybridized coordina- tion complexes, (Mn(3)2(H2O)2)- (ClO4)2 ¥2 H2 O( 5), (Mn(3)2(H2O)2)- (NO3)2 (6), (Mn(3)2(N3)2 )¥2 H2 O( 7), (Cu(3)2(H2O)2)(ClO4)2 (8), (Mn(4)2- (H2O)(SO4)) ¥ CH3OH ¥ 5 H2 O( 9) and (Mn(4)2)(ClO4)2 (10) were obtained through self-assembly of novel tripodal ligands, 1,3,5-tris(1-imidazolyl)benzene (3) and 1,3-bis(1-imidazolyl)-5-(imida- zol-1-ylmethyl)benzene (4) with the cor- responding metal salts, respectively. Their structures were determined by X-ray crystallography. The results of structural analysis of complexes 5, 6, 7, and 8 with rigid ligand 3 indicate that their structures are mainly dependant on the nature of the organic ligand and geometric need of the metal ions, but not influenced greatly by the anions and metal ions. While in complexes 9 and 10, which contain the flexible ligand 4, the counteranion plays an important role in the formation of the frameworks. En- tirely different structures of complexes 5 and 10 indicate that the organic ligands greatly affect the structures of assem- blies. Furthermore, in complexes 5 and 6, the counteranions located between the cationic layers can be exchanged by other anions. Reversible anion exchang- es between complexes 5 and 6 without destruction of the frameworks demon- strate that 5 and 6 can act as cationic layered materials for anion exchange, as determined by IR spectroscopy, elemen- tal analyses, and X-ray powder diffrac- tion.

Reversible Anion Exchanges between the Layered Organic–Inorganic Hybridized Architectures: Syntheses and Structures of Manganese(II) and Copper(II) Complexes Containing Novel Tripodal Ligands

Lu Gan

Papers

Reversible Anion Exchanges between the Layered Organic–Inorganic Hybridized Architectures: Syntheses and Structures of Manganese(II) and Copper(II) Complexes Containing Novel Tripodal Ligands