TY  - JOUR
A1  - Gole, Bappaditya
A1  - Stepanenko, Vladimir
A1  - Rager, Sabrina
A1  - Grüne, Matthias
A1  - Medina, Dana D.
A1  - Bein, Thomas
A1  - Würthner, Frank
A1  - Beuerle, Florian
T1  - Microtubular Self-Assembly of Covalent Organic Frameworks
JF  - Angewandte Chemie International Edition
N2  - Despite significant progress in the synthesis of covalent organic frameworks (COFs), reports on the precise construction of template-free nano- and microstructures of such materials have been rare. In the quest for dye-containing porous materials, a novel conjugated framework DPP-TAPP-COF with an enhanced absorption capability up to λ=800 nm has been synthesized by utilizing reversible imine condensations between 5,10,15,20-tetrakis(4-aminophenyl)porphyrin (TAPP) and a diketopyrrolopyrrole (DPP) dialdehyde derivative. Surprisingly, the obtained COF exhibited spontaneous aggregation into hollow microtubular assemblies with outer and inner tube diameters of around 300 and 90 nm, respectively. A detailed mechanistic investigation revealed the time-dependent transformation of initial sheet-like agglomerates into the tubular microstructures.
KW  - covalent organic frameworks
KW  - diketopyrrolopyrroles
KW  - imines
KW  - microtubes
KW  - porphyrins
Y1  - 2018
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-227373
VL  - 57
ER  - 
TY  - JOUR
A1  - Rager, Sabrina
A1  - Jakowetz, Andreas C.
A1  - Gole, Bappaditya
A1  - Beuerle, Florian
A1  - Medina, Dana D.
A1  - Bein, Thomas
T1  - Scaffold-Induced Diketopyrrolopyrrole Molecular Stacks in a Covalent Organic Framework
JF  - Chemistry of Materials
N2  - In recent years, covalent organic frameworks (COFs) have attracted considerable attention due to their crystalline and porous nature, which positions them as intriguing candidates for diverse applications such as catalysis, sensing, or optoelectronics. The incorporation of dyes or semiconducting moieties into a rigid two-dimensional COF can offer emergent features such as enhanced light harvesting or charge transport. However, this approach can be challenging when dealing with dye molecules that exhibit a large aromatic backbone, since the steric demand of solubilizing side chains also needs to be integrated into the framework. Here, we report the successful synthesis of DPP2-HHTP-COF consisting of diketopyrrolopyrrole (DPP) diboronic acid and hexahydroxytriphenylene (HHTP) building blocks. The well-known boronate ester coupling motif guides the formation of a planar and rigid backbone and long-range molecular DPP stacks, resulting in a highly crystalline and porous material. DPP2-HHTP-COF exhibits excellent optical properties including strong absorption over the visible spectral range, broad emission into the NIR and a singlet lifetime of over 5 ns attributed to the formation of molecular stacks with J-type interactions between the DPP subcomponents in the COF. Electrical measurements of crystalline DPP2-HHTP-COF pellets revealed conductivity values of up to 10(-6) S cm(-1).
KW  - Polymers
KW  - Electron
KW  - Design
Y1  - 2019
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-224927
VL  - 31
IS  - 8
ER  -