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  - Sanchez-Naya, Roberto
A1  - Stepanenko, Vladimir
A1  - Mandel, Karl
A1  - Beuerle, Florian
T1  - Modulation of Crystallinity and Optical Properties in Composite Materials Combining Iron Oxide Nanoparticles and Dye-Containing Covalent Organic Frameworks
JF  - Organic Materials
N2  - Two series of organic–inorganic composite materials were synthesized through solvothermal imine condensation between diketopyrrolopyrrole dialdehyde DPP-1 and 5,10,15,20-tetrakis(4-aminophenyl)porphyrin (TAPP) in the presence of varying amounts of either amino- or carboxy-functionalized superparamagnetic iron oxide nanoparticles (FeO). Whereas high FeO loading induced cross-linking of the inorganic nanoparticles by amorphous imine polymers, a lower FeO content resulted in the formation of crystalline covalent organic framework domains. All hybrid materials were analyzed by magnetization measurements, powder X-ray diffraction, electron microscopy, IR, and UV/Vis absorption spectroscopy. Crystallinity, chromophore stacking, and visible absorption features are directly correlated to the mass fraction of the components, thus allowing for a fine-tuning of materials properties.
KW  - covalent organic frameworks
KW  - diketopyrrolopyrroles
KW  - porphyrins
KW  - iron oxide nanoparticles
KW  - hybrid materials
KW  - superparamagnetism
Y1  - 2021
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-231480
VL  - 3
ER  -