The roles of imidazole ligands in coordination supramolecular systems

Abstract

Imidazole is a fundamental building unit possessing a conjugated five-membered ring system with two N-donor coordination sites. The parent imidazole nucleus can be derivatized to three types of compounds at the 1-, 2-, or 4-positions, generating 1, 2, or 4-imidazole-containing ligands, or can be endowed with other functional groups to form multi-functional ligands. Imidazole and its derivatives have been widely employed as excellent candidates for targeted metal-organic frameworks (MOFs) in the domain of coordination chemistry. Moreover, recent reports show a boom in exploratory synthesis using imidazole derivatives to construct novel MOFs due to their distinct characteristics. In consideration of the rapidly growing research on imidazole ligands, herein, we would like to highlight the recent advances in the rational design of MOFs based on imidazole derivatives from our and other research groups; we would also like to provide new insights into the rational design of organic tectons and the construction of these advanced crystalline materials with desirable properties and functionalities.

Synthesis, Crystal Structure and Water Vapor Adsorption Properties of a Porous Supramolecular Architecture

“…Generally, the metal-organic polymers are composed of the two fundamental elements of organic ligands and metal ions. Therefore, the nature of ligands and metal ions has a great influence on the structures and properties of polymers [5][6][7]. In addition, other factors including the solvent system, pH value, counterions, metal-to-ligand ratio, and reaction temperature can also decide the structures of polymers [8][9][10].…”

Synthesis, Crystal Structure, and Luminescent Properties of New Zinc(II) and Cadmium(II) Metal-Organic Frameworks Based on Flexible Bis(imidazol-1-yl)alkane Ligands

“…This results in a rather dense structure containing no residual solvent accessible voids. (14) O (14) N (13) O (13) N (12) O (12) N (11) O (11) Zn (1) O (22) N (32) Figure 8). Each SBU is joined with eight other SBUs via four bridging bdc 2− anions and four bridging C6 ligands to form 8-c uninodal net with a very rare self-penetrated topological type ilc and a point symbol 4 24 .5.6 3 [42,43].…”

“…This results in a rather dense structure containing no residual solvent accessible voids. (14) O (14) N (13) O (13) N (12) O (12) N (11) O (11) Zn (1) O (22) N (32) The asymmetric unit of the structure 3 contains three Zn(II) cations, three bdc 2− anions, and three C6 ligands. All Zn(II) cations have similar tetrahedral coordination environment built by two N atoms of two C6 ligands and two O atoms of two bdc 2− anions coordinating in a monodentate manner ( Figure 5).…”

“…Among these ligands, bis(azol-1-yl)alkanes [19,20]. Recently, several papers reporting the use of bis(imidazol-1-yl) or bis(1,2,4-triazol-1-yl) derivatives for building of coordination polymers with extended networks appeared [21][22][23][24][25][26][27][28][29][30][31][32]. In this contribution we report the synthesis of four new MOFs based on zinc(II) or cadmium(II) ions, terephthalic acid (H2bdc), and flexible ligands with longer polymethylene linkers, namely 1,5-bis(imidazol-1-yl)pentane (C5) or 1,6-bis(imidazol-1-yl)hexane (C6), synthesized by an improved procedure, which is also described here.…”

Synthesis, Crystal Structures, and Photoluminescent Properties of Two Supramolecular Architectures Based on Difunctional Ligands Containing Imidazolyl and Carboxyl Groups

“…The rational design and construction of metal-organic frameworks (MOFs) has become an expanding research topic in the fields of supramolecular chemistry and crystal engineering not only because of their intriguing molecular architectures and intricate topologies but also their promising applications in various areas in fluorescence, gas adsorption, separation, ion exchange, magnetic properties, catalysis, and so on [1][2][3][4][5][6]. Because the complexes incorporate metallic centers and bridging organic linkers, therefore, it is important to design suitable organic ligands and choose metallic centers to assemble desirable frameworks with specific structures and functions.…”