Metal–Organic Gels Based on a Bisamide Tetracarboxyl Ligand for Carbon Dioxide, Sulfur Dioxide, and Selective Dye Uptake

Abstract

A metal–organic gel (metallogel) based on the new tetracarboxyl ligand N 1,N 4-(diterephthalic acid)­terephthalamide in combination with chromium­(III) has been converted into its xero- and aerogel and demonstrated to have excellent specific sorption properties for dyes in its metallogel state, where fuchsine is adsorbed faster than the two other dyes, calcein and disulfine blue, and for water, sulfur dioxide and carbon dioxide in its xero- and aerogel state. The metallogel showed very good shape retention and could be extruded from molds in designed shapes. In a rheology experiment, the storage modulus was determined to be 1440 Pa, and the metallogel is elastic up to 3 Hz, breaking at strains higher than 0.3%. Additional metallogels utilizing the same ligand with a wide range of metal ions (Al­(III), Fe­(III), Co­(III), In­(III), and Hg­(II)) have also been synthesized, and the aluminum and mixed aluminum–chromium derivative were also converted into its aerogel. The highly porous Cr, Al, and AlCr metal–organic aerogels proved stable against water vapor in a physisorption experiment and were used to model breakthrough curves for SO2/CO2 gas mixtures with the idealized adsorbed solution theory from their physisorption isotherms. The breakthrough simulation utilized SO2/CO2 equivalencies from a real world application and showed effective retention of SO2 from the gas mixture. Furthermore, the materials in this work exhibit the highest SO2 uptake values for metal–organic aerogels so far (up to 116.8 cm3 g–1, or 23.4 wt %).

In2S3‐Polymer Hybrid Gels Derived from In(III) Metal–Organic Gels for Dye Adsorption, Photodegradation, and Bacteria Removal

“…[32,33] On the one hand, dye adsorption could be utilized to purify wastewater. Some researchers have reported the use of functional gels as adsorbents due to their large specific surface area, [34][35][36] and notably, Sureshan and co-workers prepared a kind of hybrid gel as a dyestuff scavenger by gel template synthesis. [37] However, the amount of adsorption is always limited by the efficiency of the adsorbent.…”

Tunable Metallogels Based on Bifunctional Ligands: Precursor Metallogels, Spinel Oxides, Dye and CO2 Adsorption

“… 32 The desolvated metallogels, viz., xerogels, are functionalized materials that can play an essential role as single-source precursors of metal oxides for energy applications and in environmental remediation. 13 − 15 , 33 − 35 …”

“…The self-assembled semisolid gel materials derived from the low-molecular-weight gelator are called metallogels in the presence of a metal ion, otherwise termed as organogels . Particularly, the design of metal-incorporated gel materials is challenging and appealing because metal imparts several functional properties into the material, like conductivity, , absorption/ion-exchange, − catalytic applications, , redox activity, and other energy-related applications. , Noncovalent interactions like π–π interactions, hydrophobic interactions, , hydrogen bonding, and electrostatic forces imparted the three-dimensional metallogel network , with immobilized solvent in the gel network. In metallogels, the cross-linked network structure is stable and formed via the metal–ligand interaction that can be tuned by replacing the metal ions .…”

“…Metallogels find applications in fields such as light-emitting diodes, sensors, biomaterials, , and photonics . The desolvated metallogels, viz., xerogels, are functionalized materials that can play an essential role as single-source precursors of metal oxides for energy applications and in environmental remediation. − ,− …”

A Superstable Luminescent Lanthanide Metal Organic Gel Utilized in an Electrochemiluminescence Sensor for Epinephrine Detection with a Narrow Potential Sweep Range

“…It can be rapidly synthesized at room temperature through metal ligand coordination (coordination bond) and noncovalent interactions (π–π stacking, hydrogen bond, van der Waals forces, etc.) and has been applied in catalysis, adsorption, and sensors. ,, During the MOG synthesis process, metal ions such as lanthanide ions are usually selected as coordination center atoms, and compounds containing a carboxyl group or pyridine ring such as 4′-(4-carboxyphenyl)-2,2′:6′,2″-terpyridine (Hcptpy) or 1,3,5-benzenetricarboxylic acid (H 3 BTC) are usually selected as ligands. ,− Lanthanide ions such as Tb 3+ own unique optical properties (4f n shell of the [Xe]­5s 2 5p 6 configuration), for example, the high quantum yield, narrow and stable emission peaks, and long luminescence lifetime. ,, Compounds containing a carboxyl group or pyridine ring possess the ability to form thermodynamically stable coordination bonds with lanthanide ions and also can effectively sensitize the lanthanide-centered emission. ,, Considering the unique optical properties and long luminescence lifetime, lanthanide ion-based MOGs have become the most promising luminophores in the ECL field. Although the innovative application of terbium organic gels in an ECL sensor has been reported, the research of MOGs in ECL is still in its infancy.…”