3D Covalent Organic Frameworks of Interlocking 1D Square Ribbons

Abstract

A new mode of mechanical entanglement in extended structures is described where 1D organic ribbons of cornersharing squares are mutually interlocked to form 3D woven covalent organic framework-500, COF-500. Reaction of aldehydefunctionalized tetrahedral Cu(PDB)2PO2Ph2 complexes (PDB = 4,4'-(1,10-phenanthroline-2,9-diyl)dibenzaldehyde) with rectangular tetratopic ETTBA ((ethene-1,1,2,2-tetrayl)tetrakis([1,1'-biphenyl]-4-amine)) linkers through imine condensation, yielded a crystalline porous metalated COF, COF-500-Cu, with pts topology. Upon removal of the Cu(I) ions, the individual 1D square ribbons in the demetalated form (COF-500) are held together only by mechanical interlocking of rings that allows their collective movement to produce a narrow-pore form as evidenced by nitrogen adsorption and solid-state photoluminescence studies. When exposed to tetrahydrofuran vapor, the interlocking ribbons can dynamically move away from each other to reopen up the structure. The structural integrity of COF-500 is maintained during its dynamics because the constituent square ribbons cannot part company due to spatial confinement imparted by their interlocking nature.

Single crystal of a one-dimensional metallo-covalent organic framework

“…Along with the poly-condensation reaction, the constituents are consumed and regenerated from the reactant "pool" 33 . An advantage of this method is that building blocks can evolve into multiintermediates through reversible reactions or interactions without the need to synthesise each building block individually, which is distinct from the conventional methods of making crystalline organic networks using predetermined building blocks 34,35 .…”

Polymer Networks: From Plastics and Gels to Porous Frameworks

“…The copper(I) ions could be reversibly removed from this material and added back without loss of the COF structure. Following a similar approach by replacing benzidine with a rectangular tetrafunctional linker, another three‐dimensional woven COF (COF‐500) was recently reported, where one‐dimensional organic ribbons of corner‐sharing squares were mutually interlocked …”

“…[237] Thec opper(I) ions could be reversibly removed from this material and added back without loss of the COF structure.F ollowing as imilar approach by replacing benzidine with arectangular tetrafunctional linker,a nother three-dimensional woven COF (COF-500) was recently reported, where one-dimensional organic ribbons of corner-sharing squares were mutually interlocked. [238] While dynamic covalent bonds facilitate the crystallinity of COFs,t he same mechanism results in their low chemical/ hydrolytic stability and severely limits their potential applications.T hree strategies have been applied to increase COF stability:1 )Using more stable dynamic covalent bonds.F or example,h ydrazone-or azine-linked COFs were shown to have ah igher hydrolytic stability than imine-linked COFs; [239,240] 2) Strengthening the interlayer stacking in twodimensional COFs. [241,242] Fore xample,J iang and co-workers developed as table imine-linked COF by incorporating methoxy groups into the pore walls, [243] which softened interlayer charge repulsion and reinforced interlayer hydrogen bonding; [244] and 3) Post-synthetic modification that converts reversible bonds to irreversible bonds while main-Angewandte Chemie Reviews taining crystallinity.F or example,i n2 012, Banerjee and coworkers synthesized an enol-imine COF intermediate through reversible Schiff base condensation between 1,3,5triformylphloroglucinol and aromaticdiamines.…”

Polymernetzwerke: Von Kunststoffen und Gelen zu porösen Gerüsten

“…Die Kupfer(I)‐Ionen konnten reversibel aus diesem Material entfernt und wieder angelagert werden, ohne dass die COF‐Struktur beeinträchtigt wurde. Unter Verfolgung eines ähnlichen Ansatzes unter Ersetzen von Benzidin durch einen rechteckigen tetrafunktionellen Linker, wurde vor kurzem ein anderes dreidimensionales verschlungenes COF (COF‐500) beschrieben, wobei eindimensionale Polymerbänder aus Quadraten mit gemeinsamen Ecken gegenseitig verriegelt waren …”

“…[237] Die Kupfer(I)-Ionen konnten reversibel aus diesem Material entfernt und wieder angelagert werden, ohne dass die COF-Struktur beeinträchtigt wurde.U nter Verfolgung eines ähnlichen Ansatzes unter Ersetzen von Benzidin durch einen rechteckigen tetrafunktionellen Linker,w urde vor kurzem ein anderes dreidimensionales verschlungenes COF (COF-500) beschrieben, wobei eindimensionale Polymerbänder aus Quadraten mit gemeinsamen Ecken gegenseitig verriegelt waren. [238] Während dynamische kovalente Bindungen die Kristallinitätv on COFs fçrdern, hat derselbe Mechanismus eine ge- [239,240] 2) Erhçhung der Festigkeit zwischen den gestapelten Schichten in zweidimensionalen COFs. [241,242] So entwickelten Jiang und Mitarbeiter ein stabiles COF mit Iminverknüpfungen durch den Einbau von Methoxygruppen in seine Porenwandungen, [243] die die Ladungsabstoßung zwischen den Schichten abschwächten und die Wasserstoffbrücken zwischen den Schichten verstärkten.…”