Gas Adsorption, Proton Conductivity, and Sensing Potential of a Nanoporous Gadolinium Coordination Framework

Abstract

The new nanoporous framework [Gd 4 (di-nitro-BPDC) 4 (NO 2 ) 3 (OH)(H 2 O) 5 ]•(solvent) (I; di-nitro-BPDC 2− = 2,2′-dinitrobiphenyl-4,4′-dicarboxylate) has been designed and synthesized through a simple one-pot reaction. In addition to its exceptional thermal and water stabilities, I exhibited multifunctional properties. A sudden CO 2 uptake to a maximum of 4.51 mmol g −1 (195 K and 1 bar) with notable selectivity over O 2 and N 2 (CO 2 /O 2 = 39 at 195 K and 0.10 bar, CO 2 /N 2 = 46 at 195 K and 0.10 bar) and an isosteric adsorption enthalpy of 20.7(4) kJ mol −1 have been revealed. Depending on the temperature and humidity, I also showed distinguished superprotonic conductivities with a maximum value and activation energy of 6.17 × 10 −2 S cm −1 (55 °C, 99 RH%, and 1 V AC voltage) and 0.43 eV, respectively. With respect to the linear dependence of conductivities on both temperature (25−55 °C at 99 RH%) and humidity (55−99 RH% at 25 °C), the potential of I in temperature and humidity sensing was evaluated, disclosing an excellent sensing resolution and exceptional accuracy, precision, and repeatability for the measurements.

Ultrahigh Proton Conductivities of Postmodified Hf(IV) Metal–Organic Frameworks and Related Chitosan-Based Composite Membranes

“…MOFs can be used as good proton conductors for the following reasons: first, MOFs contain rich H-bonded networks and H 2 O units for efficient proton transport; second, crystalline products of MOFs could be easy to get, which supplies a convenient way to explore the conducting mechanism; third, their σ can be adjusted by choosing variable modification methods. − Currently, the modification strategies of proton-conductive MOFs could be broadly classified into two types: (1) By modification of organic ligands, acidic units (carboxylate, phosphonate, −SO 3 H, −OH, etc.) could be introduced into the framework to increase its acidity and hydrophilicity, thus enhancing the σ. − Note that people can regulate the composition of MOFs through chemical modification, to change the pore structures and the surface structures of MOFs, and introduce other functional groups or heteroatoms, resulting in changes in their function and expand their application scope and value. , (2) The anchoring of small units or ions (water, imidazole, triazole, histamine, etc.)…”

Adsorption Behavior of a Gd-Based Metal–Organic Framework toward the Quercetin Drug: Effect of the Activation Condition

“…Gd complexes, used as commercial diagnostic CAs today, have some downfalls such as low circulation time in the body, functionalization limits in case of need such as surface modification for crossing the blood–brain barrier, and toxicity due to high dose injection of Gd solution to get qualified contrasted images . To overcome these drawbacks, Gd-MOFs including Gd ions as nodes chelated with carboxylic ligands as struts are the best candidates for MRI agents thanks to their intense relaxivities due to the presence of a high concentration of Gd ions per MOF particle, biocompatibility because of the surrounding ligand which blocks interactions between toxic Gd ions and cell tissues, and facility of ligand modifications by specific peptides or polymers for targeted drug delivery, detection, or bioimaging. , Although Gd-MOFs have attracted much attention in the MRI field, their low specific surface area, for example, 2–11 m 2 /g, is considered disadvantage for use in drug delivery systems and theragnostic agents. − …”

Easy Handling and Cost-Efficient Processing of a Tb3+-MOF: The Emissive Capacity of the Membrane-Immobilized Material, Water Vapour Adsorption and Proton Conductivity

“…In the case of 1, at temperatures higher than 60 • C and RH ≥ 40%, the conductivity started to decrease, possibility due to some sort of phase transition or to a degradation in particle connectivity due to the presence of an increasing number of water molecules. The maximum ionic conductivity observed for 1 was 3.2 × 10 −8 Scm −1 at 60 • C and 95% RH, which is a relatively modest value when compared with the conductivity of other 3D carboxylate-based MOFs, which ranges from 10 −6 to 10 −2 Scm −1 (Table S7) [28][29][30][31][32][33][34][35][36][37].…”