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

Abstract

Engineering high-recognition host-guest materials is aburgeoning area in basic and applied research. The challenge of exploring novel porous materials with advanced functionalities prompted us to develop dynamic crystalline structures promoted by soft interactions.T he first example of ap ure molecular dynamic crystalline framework is demonstrated, which is held together by means of weak "stickyf ingers" van der Waals interactions.T he presented organic-fullerene-based material exhibits an on-porous dynamic crystalline structure capable of undergoing single-crystal-to-single-crystal reactions.E xposure to hydrazine vapors induces structural and chemical changes that manifest as toposelective hydrogenation of alternating rings on the surface of the [60]fullerene.Control experiments confirm that the same reaction does not occur when performed in solution. Easy-to-detect changes in the macroscopic properties of the sample suggest utility as molecular sensors or energy-storage materials.One of the important challenges in chemical science nowadays is the search for greener processes for ac leaner world. [1] In chemistry,t his usually translates into highly selective reactions with high rates and efficiencies. [2] Recently, novel synthetic strategies were proposed that diverge from classical approaches.While the latter are usually based on the temperature,p ressure,a nd exact formulation control, reac-tivity control of the former explores novel environmental strategies (for example,t he successful surface chemistry approach, [3] chemical topology, [4] or chemical reactions performed in confined spaces [5] in which the reactivity differs in many aspects from those conducted in bulk solution). 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. [11] MOFs offer improved flexibility compared to rigid zeolites and less processable COFs. [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...

Playing with the weakest supramolecular interactions in a 3D crystalline hexakis[60]fullerene induces control over hydrogenation selectivity

“…This color change is indicative of the partial hydrogenation of 2 by hydrazine. 22 The resulting material attained by SCSC reaction, namely 2hyd , agrees with the C 126 H 132 O 24 formulation, with twenty-four hydrogen atoms more than 2 (C 126 H 108 O 24 ). The new material is stable under atmospheric conditions and highly soluble in common organic solvents such as CH 2 Cl 2 , CH 3 Cl, and acetone.…”

“…On the other hand, polymorph 3 (ref. 22 ) crystallizes in a different space group from 2 , namely in a cubic Fd 3̄. The unit cell is composed of eight symmetry equivalent hexaadducts placed in four unequal layers.…”

“…[14][15][16][17][18][19][20][21] Our research group has recently reported the rst example of a van der Waals "sticky ngers" crystalline structure of a C 60 hexakis-adduct (herein aer referred as 3). 22 The sum of several dihydrogen vdW interactions between interdigitated butyl malonate units attached to neighboring [60]fullerenes has been revealed as the driving force for the crystallization of a robust, purely molecular, dynamic framework of hexakis [60]fullerene adducts. This framework provides the excellent scaffolding for testing a new topochemical solid-vapor reaction.…”

A switchable iron-based coordination polymer toward reversible acetonitrile electro-optical readout

“…These materials contain the voids necessary to absorb guest molecules, thereby changing their properties. Recently, more attention has been paid to materials where in the absence of pores an exchange might still take place through the process of diffusion throughout the crystal lattice 6. This process may produce an easy-to-measure response due to the variation of the macroscopic properties of these materials, in agreement with the definition of a chemosensor 7.…”

A supramolecular polymeric heterojunction composed of an all-carbon conjugated polymer and fullerenes

“…For a long time, fullerenes have been widely studied as guests in various organic host architectures owing to their unusual shape (approximately spherical) and chemical nature (nonpolar polyenes). 55 These organic host architectures have specic sizes for C 60 to construct various host-guest molecular systems via supramolecular interactions and weak supramolecular van der Waals interactions, such as supramolecular organic frameworks, 64 cyclodextrin, 65 calix [8]arene, 66 crown ether, 67,68 macrocyclic bis-exTTF hosts, 50 and nanorings. 51,69 Cyclo-paraphenylene with ten phenyl groups has an appropriate size to complex with C 60 , as evidenced by single crystal X-ray diffraction analysis and NMR studies.…”