Biplab Manna

A Water‐Stable Cationic Metal–Organic Framework as a Dual Adsorbent of Oxoanion Pollutants

A three-dimensional water-stable cationic metal-organic framework (MOF) pillared by a neutral ligand and with Ni(II)  metal nodes has been synthesized employing a rational design approach. Owing to the ordered arrangement of the uncoordinated tetrahedral sulfate (SO4 (2-) ) ions in the channels, the compound has been employed for aqueous-phase ion-exchange applications. The compound exhibits rapid and colorimetric aqueous-phase capture of environmentally toxic oxoanions (with similar geometries) in a selective manner. This system is the first example of a MOF-based system which absorbs both dichromate (Cr2 O7 (2-) ) and permanganate (MnO4 (-) ) ions, with the latter acting as a model for the radioactive contaminant pertechnetate (TcO4 (-) ).

Framework-Flexibility Driven Selective Sorption of p -Xylene over Other Isomers by a Dynamic Metal-Organic Framework

Chemical separation has great importance in industrial applications. Separation of xylene isomers still prevails to be one of the most important challenges in chemical industry, due to the large amount of commercial use of p-xylene in the production of beverage bottles, fibers and films. A novel Zn(II)-based dynamic coordination framework based on flexible ether-linkage, exhibiting selective adsorption of p-Xylene over its congener C8-alkyl aromatic isomers at ambient conditions is reported. Notably, no dynamic structure based MOF compound is known in the literature which shows clear preference of p-xylene over other isomers. This type of framework-breathing and guest-induced reversible solid-state structural transformations with unique adsorption selectivity can be exploited purposefully to develop smart functional host materials capable of industrially important chemical separations.

Selective anion exchange and tunable luminescent behaviors of metal-organic framework based supramolecular isomers.

Owing to the conformational (cis or trans) flexibility of a N-donor ligand, the combinations of the same and Cd(ClO4)2 under variable solvent templates afforded two supramolecular isomers based on two-dimensional metal-organic frameworks. Both compounds contain weakly coordinating ClO4(-) anions attached to the metal centers. Both frameworks showed facile anion exchange behaviors with various kinds of foreign anions. Moreover, both frameworks showed anion-driven structural dynamism and exhibited the preferential uptake of strongly coordinating anions over others. Anion-regulated modulation in luminescent behaviors was also observed in both cases.

An Amide‐Functionalized Dynamic Metal–Organic Framework Exhibiting Visual Colorimetric Anion Exchange and Selective Uptake of Benzene over Cyclohexane

A novel porous metal-organic framework (MOF) architecture is formed by a neutral amide-functionalized ligand and copper(II). Upon desolvation, this compound undergoes a dynamic structural transformation from a one-dimensional (1D) porous phase to a two-dimensional (2D) non-porous phase that shows selective uptake of benzene over cyclohexane. The as-synthesized compound also acts as a visual colorimetric anion sensor for thiocyanate.

Exploiting Framework Flexibility of a Metal-Organic Framework for Selective Adsorption of Styrene over Ethylbenzene

The separation of styrene and ethylbenzene mixtures is industrially important and is currently performed in highly energy-intensive vacuum distillation columns. The primary objective of our investigation is to offer an energy-efficient alternative for selective adsorption of styrene by a flexible metal-organic framework, DynaMOF-100. The structural transformation of DynaMOF-100 is specifically triggered on inclusion of styrene within the framework; this structural transformation is reversible. The styrene/ethylbenzene adsorption selectivity, originated as an outcome of the framework flexibility, is found to be much superior to the only two MOFs yet reported, serving styrene/ethylbenzene separation purpose.

Amino Acid Based Dynamic Metal–Biomolecule Frameworks

On the move: Two isostructural, homochiral Cu(II) coordination frameworks based on amino acids (D- and L-PGA) were synthesized. Dynamic behavior by solid-state structural transformation in single-crystal-to-single-crystal fashion was demonstrated. The extent of structural dynamism was shown by guest inclusion studies. Reversible sol-gel formation and anion-tuning morphology of the compounds is also discussed.

An Ultrahydrophobic Fluorous Metal–Organic Framework Derived Recyclable Composite as a Promising Platform to Tackle Marine Oil Spills

Derived from a strategically chosen hexafluorinated dicarboxylate linker aimed at the designed synthesis of a superhydrophobic metal-organic framework (MOF), the fluorine-rich nanospace of a water-stable MOF (UHMOF-100) exhibits excellent water-repellent features. It registered the highest water contact angle (≈176°) in the MOF domain, marking the first example of an ultrahydrophobic MOF. Various experimental and theoretical studies reinforce its distinctive water-repellent characteristics, and the conjugation of superoleophilicity and unparalleled hydrophobicity of a MOF material has been coherently exploited to achieve real-time oil/water separation in recyclable membrane form, with significant absorption capacity performance. This is also the first report of an oil/water separating fluorinated ultrahydrophobic MOF-based membrane material, with potential promise for tackling marine oil spillages.

Guest‐Responsive Function of a Dynamic Metal–Organic Framework with a π Lewis Acidic Pore Surface

A 3D dynamic coordination framework with an electron-deficient pore surface has been synthesized by using Zn(II) (having a variable coordination number) and a predesigned flexible π-electron-deficient core-based ligand, exhibiting chemical separations based on pore surface functionalization (π Lewis acidic pore surfaces and open metal sites) and framework flexibility, giving rise to a unique smart guest-responsive material.

Anion‐Responsive Tunable Bulk‐Phase Homochirality and Luminescence of a Cationic Framework

Reaction of a linear bi-chelating N-donor achiral ligand with Zn(II) afforded a homochiral cationic framework with six-fold one-dimensional helical chains. The compound showed selective anion exchange behavior with interesting anion-responsive tunable bulk-phase homochirality. The cationic framework also presented anion-driven variable luminescence and sorption behavior.

A π-electron deficient diaminotriazine functionalized MOF for selective sorption of benzene over cyclohexane

A diaminotriazine functionalized novel MOF (DAT-MOF-1) has been synthesized stemming out of a π-electron-deficient pore-surface functionalization based linker-design principle, which results in efficient selectivity of benzene sorption over its aliphatic analogue cyclohexane, crucial from the industrial standpoint.