In situ conversion of a MOG to a crystalline MOF: a case study on solvent-dependent gelation and crystallization

Herein, we report in situ transformation of a metal-organic gel (MOG) to a crystalline metal-organic framework (MOF) and solvent-dependent gelation/crystallization via solvothermal reactions of a tetracarboxylic acid, namely 4,4'-dinitro-2,2',6,6'-tetracarboxybiphenyl, and ZnSO₄. The results provide structural insights into MOGs at the molecular level and also help in the synthesis of crystalline MOFs that are otherwise difficult to obtain.

Hierarchical porous metal–organic gels and derived materials: from fundamentals to potential applications

This review summarizes recent progress in the development and applications of metal–organic gels (MOGs) and their hybrids and derivatives dividing them into subclasses and discussing their synthesis, design and structure–property relationship.

Effect of pyridyl donors from organic ligands versus metalloligands on material design

This review illustrates designs and structures of various coordination frameworks constructed using assorted organic ligands and metalloligands offering pyridyl donors to evaluate the impact of flexibility versus rigidity on material design.

Infinite coordination polymer networks: metallogelation of aminopyridine conjugates and in situ silver nanoparticle formation

Herein we report silver(i) directed infinite coordination polymer network (ICPN) induced self-assembly of low molecular weight organic ligands leading to metallogelation. Structurally simple ligands are derived from 3-aminopyridine and 4-aminopyridine conjugates which are composed of either pyridine or 2,2'-bipyridine cores. The cation specific gelation was found to be independent of the counter anion, leading to highly entangled fibrillar networks facilitating the immobilization of solvent molecules. Rheological studies revealed that the elastic storage modulus (G') of a given gelator molecule is counter anion dependent. The metallogels derived from ligands containing a bipyridine core displayed higher G' values than those with a pyridine core. Furthermore, using single crystal X-ray diffraction studies and ¹H-¹⁵N two-dimensional (2D) correlation NMR spectroscopy, we show that the tetracoordination of silver ions enables simultaneous coordination polymerization and metallosupramolecular cross-linking. The resulting metallogels show spontaneous, in situ nanoparticle (d < 2-3 nm) formation without any additional reducing agents. The silver nanoparticle formation was followed using spectroscopic studies, and the self-assembled fibrillar networks were imaged using transmission electron microscopy (TEM) imaging.

MOF the beaten track: unusual structures and uncommon applications of metal-organic frameworks

Over the past few decades, metal-organic frameworks (MOFs) have proved themselves as strong contenders in the world of porous materials, standing alongside established classes of compounds such as zeolites and activated carbons. Following extensive investigation into the porosity of these materials and their gas uptake properties, the MOF community are now branching away from these heavily researched areas, and venturing into unexplored avenues. Ranging from novel synthetic routes to post-synthetic functionalisation of frameworks, host-guest properties to sensing abilities, this review takes a sidestep away from increasingly 'traditional' approaches in the field, and details some of the more curious qualities of this relatively young family of materials.

Trace-doped metal–organic gels with remarkably enhanced luminescence

Novel highly luminescent metal–organic gels with a trace amount of doping (as low as 0.01 mol%) have been fabricated.