Terpyridine‐Based 3D Metal–Organic‐Frameworks: A Structure–Property Correlation

Abstract

Design, synthesis, and applications of metal–organic frameworks (MOFs) are among the most salient fields of research in modern inorganic and materials chemistry. As the structure and physical properties of MOFs are mostly dependent on the organic linkers or ligands, the choice of ligand system is of utmost importance in the design of MOFs. One such crucial organic linker/ligand is terpyridine (tpy), which can adopt various coordination modes to generate an enormous number of metal–organic frameworks. These frameworks generally carry physicochemical characteristics induced by the π‐electron‐rich (basically N‐electron‐rich moiety) terpyridines. In this minireview, the construction of 3D MOFs associated with symmetrical terpyridines is discussed. These ligands can be easily derivatized at the lateral phenyl (4′‐phenyl) position and incorporate additional organic functionalities. These functionalities lead to some different binding modes and form higher dimensional (3D) frameworks. Therefore, these 3D MOFs can carry multiple features along with the characteristics of terpyridines. Some properties of these MOFs, like photophysical, chemical selectivity, photocatalytic degradation, proton conductivity, and magnetism, etc. have also been discussed and correlated with their frameworks.

Stars and stripes: hexatopic tris(3,2′:6′,3′′-terpyridine) ligands that unexpectedly form one-dimensional coordination polymers

“…17 A contrasting approach is to employ oligopyridines with divergent sets of donor atoms. Of all the isomers, however, only the symmetrical 4,2′:6′,4″-tpy and 3,2′:6′,3″-tpy have been widely used in the last decade, 15,[18][19][20][21][22] along with their 4′functionalized derivatives which are readily accessible using either Wang and Hanan's one-pot synthetic approach 23 or the Kröhnke methodology. 24 The ligands 4,2′:6′,4″-tpy and 3,2′:6′,3″-tpy coordinate through the outer pyridine donors, leaving the central pyridyl-N atom unbound (Scheme 1).…”

“…24 The ligands 4,2′:6′,4″-tpy and 3,2′:6′,3″-tpy coordinate through the outer pyridine donors, leaving the central pyridyl-N atom unbound (Scheme 1). CPs with uncoordinated Lewis-base sites within solvent-accessible channels have been considered as potential candidates for small-molecule and ion detection applications, 15,22,[25][26][27] e.g. through C-H⋯N pyridine hydrogen bond formation.…”

“…Terpyridine (tpy) ligands are well-established N-donors in coordination chemistry, and have therefore long been successfully exploited for the assembly of discrete and polymeric coordination complexes. 15 Of the 48 possible isomeric terpyridines, 2,2′:6′,2′′-tpy is the archetypal. It is a monotopic chelating ligand, although the 2:2′:6′,2′′-tpy domain also exhibits multiple metal-binding modes.…”

“…through C–H⋯N pyridine hydrogen bond formation. 15 These tpy isomers possess different vectorial properties of the N-donor set ( Scheme 1 ). While 4,2′:6′,4′′-tpy offers a fixed V-shaped metal-binding domain, the less explored isomer 3,2′:6′,3′′-tpy has a greater conformational flexibility which arises from rotation about the inter-ring C–C bonds connecting the pyridine rings leading to a more variable and less predictable network assembly.…”

One-Step Electrochemical Growth of 2D/3D Zn(II)-MOF Hybrid Nanocomposites on an Electrode and Utilization of a PtNPs@2D MOF Nanocatalyst for Electrochemical Immunoassay

“…21,22 However, it still remains a big challenge to synthesize 2D MOFs because the growth of MOF crystals should be suppressed to the nanometer scale only along the vertical direction and not affect the other two lateral directions. 11 Furthermore, 3D MOFs not only have multiple features along with characteristics of 2D MOFs 23,24 but can also be used as sensors. 25−27 A common organic ligand, 1,3,5benzenetricarboxylic acid (H 3 BTC), has been used to fabricate various functional 3D MOFs.…”