Selective CO₂ Adsorption in a Supramolecular Organic Framework

Abstract

Considering the rapidly rising CO2 level, there is a constant need for versatile materials which can selectively adsorb CO2 at low cost. The quest for efficient sorptive materials is still on since the practical applications of conventional porous materials possess certain limitations. In that context, we designed, synthesized, and characterized two novel supramolecular organic frameworks based on C-pentylpyrogallol[4]arene (PgC5 ) with spacer molecules, such as 4,4'-bipyridine (bpy). Highly optimized and symmetric intermolecular hydrogen-bonding interactions between the main building blocks and comparatively weak van der Waals interactions between solvent molecules and PgC5 leads to the formation of robust extended frameworks, which withstand solvent evacuation from the crystal lattice. The evacuated framework shows excellent affinity for carbon dioxide over nitrogen and adsorbs ca. 3 wt % of CO2 at ambient temperature and pressure.

Process Development for Separation of Conformers from Derivatives of Resorcin[4]arenes and Pyrogallol[4]arenes

“…These noncovalent interactions majorly involved hydrogen bond, halogen bond, cation–π, π–π interactions, and/or van der Waals forces. SOFs have gathered the attention of scientific world in recent times due to their fascinating applications in the fields, such as selective gas sorption/separation, catalysis, medicinal chemistry, and electronics . The properties of these SOFs are manipulated through meticulous engineering of the intermolecular interactions between the components of the frameworks.…”

“…The bowl‐shaped cavity of the RsC and PgC also works as perfect host for guest molecules of different shapes and functionalities . These structural features are useful not only in the construction of various supramolecular frameworks, such as hydrogen‐bonded dimers/hexamers and metal‐seamed dimers/hexamers, but also in the applications of RsC and PgC in the field of, for example, molecular recognition, host–guest complexes, gas sorption and separation …”

Formation of Water Channels in the Crystalline Hydrates of Macrocyclic Compounds

“…Unique cyclic shape and ability to carry different functional groups make macrocyclic compounds eligible for applications in the fields such as pharmaceuticals, chromatography, nanotechnology, and gas sorption/separation . For example, cyclodextrin, a cyclic oligomer of glucose has proven to be useful in pharmaceutical product development owing to higher water solubility and ability to form stable inclusion complex with drug molecules .…”

A Three‐Dimensional Dynamic Supramolecular “Sticky Fingers” Organic Framework

“…[1] In chemistry,t his usually translates into highly selective reactions with high rates and efficiencies. [12] This flexibility could generate novel dynamic adsorption properties under realistic conditions-similar to the liquid-protein reactions that occur for specific interactions between an enzymatic host and as ubstrate.P ure organic systems usually demonstrate excellent properties,s uch as high thermal stabilities,t unable structural properties,a nd biocompatibility;h owever,t hey also present drawbacks,s uch as rigidity and limited processability.T herefore,t he formation of dynamic structures (porous or non-porous acting as porous) by means of supramolecular interactions between molecules might be an interesting alternative.H owever,t he crystallization of stable organic structures possessing porosity or showing the ability to incorporate molecules by internal structural reorganization (breathing effect) is still areal challenge,with some examples reported using hydrogen bonding [8,[13][14][15][16][17][18][19][20][21][22] or p-p stacking [8,[23][24][25] as adriving force.In this manuscript, we report for the first time how af lexible non-porous organic molecule connected through supramolecular van der Waals interactions,s o-called "sticky fingers", [26] behaves as an excellent dynamic molecular receptor.F urthermore,t he inclusion of small molecules inside this material allows an unprecedented hydrogenation reaction that occurs only in ac onfined crystalline space and not by traditional wet chemistry.The reaction is performed in as ingle-crystal-to-single-crystal (SCSC) fashion, which has allowed us to study how this material behaves upon the inclusion of these small molecules with atomic detail. In that sense,p orous materials connected by intermolecular bonds (such as,m etal-organic frameworks [6] (MOFs), covalent organic frameworks [7] (COFs), or porous molecular materials [8] that are built from discrete molecules [9] such as porous organic cages) [10] have provided notable results.The discovery and development of these materials has spurred an interest in confined chemical reactions to determine how spatial confinement can influence the yields and reactivity pathways of reactions.…”

“…In that sense,p orous materials connected by intermolecular bonds (such as,m etal-organic frameworks [6] (MOFs), covalent organic frameworks [7] (COFs), or porous molecular materials [8] that are built from discrete molecules [9] such as porous organic cages) [10] have provided notable results.The discovery and development of these materials has spurred an interest in confined chemical reactions to determine how spatial confinement can influence the yields and reactivity pathways of reactions. [12] This flexibility could generate novel dynamic adsorption properties under realistic conditions-similar to the liquid-protein reactions that occur for specific interactions between an enzymatic host and as ubstrate.P ure organic systems usually demonstrate excellent properties,s uch as high thermal stabilities,t unable structural properties,a nd biocompatibility;h owever,t hey also present drawbacks,s uch as rigidity and limited processability.T herefore,t he formation of dynamic structures (porous or non-porous acting as porous) by means of supramolecular interactions between molecules might be an interesting alternative.H owever,t he crystallization of stable organic structures possessing porosity or showing the ability to incorporate molecules by internal structural reorganization (breathing effect) is still areal challenge,with some examples reported using hydrogen bonding [8,[13][14][15][16][17][18][19][20][21][22] or p-p stacking [8,[23][24][25] as adriving force. [12] This flexibility could generate novel dynamic adsorption properties under realistic conditions-similar to the liquid-protein reactions that occur for specific interactions between an enzymatic host and as ubstrate.P ure organic systems usually demonstrate excellent properties,s uch as high thermal stabilities,t unable structural properties,a nd biocompatibility;h owever,t hey also present drawbacks,s uch as rigidity and limited processability.T herefore,t he formation of dynamic structures (porous or non-porous acting as porous) by means of supramolecular interactions between molecules might be an interesting alternative.H owever,t he crystallization of stable organic structures possessing porosity or showing the ability to incorporate molecules by internal structural reorganization (breathing effect) is still areal challenge,with some examples reported using hydrogen bonding [8,…”