The chiroptical features of supramolecular polymers formed from N-heterotriangulenes 1-3 have been investigated by circular dichroism (ECD) and vibrational circular dichroism (VCD) techniques. In solution, the CD spectra demonstrate that the helicity of the aggregates depends on only the stereogenic centres located at the peripheral chains. In the gel state, the chiroptical features are conditioned by the point chirality of the stereogenic centres and by the achiral solvent utilised. Sonication of the gels formed in CCl reveals both kinetic and thermodynamic phases. These findings reveal the presence of pathway complexity in the gel state triggered by sonication. The described solvent-induced helical stereomutation demonstrates that the gel state can be utilised as an outstanding benchmark for investigating uncommon chiroptical effects and to explore the rules of chirality transmission.
Ac omparative investigationo ft he chiral amplification features of as eries of three families of C 3-symmetric tricarboxamides, 1,3,5-triphenylbenzenetricarboxamides (TPBAs), benzenetricarboxamides(BTAs) and oligo(phenylene ethynylene) tricarboxamides (OPE-TAs), is here reported. As previously observed for BTAs and OPE-TAs, as imilard ichroic response is obtained for TPBAsd ecorated with one, two or three chiral side chains bearing stereogenic centers, thus confirming the efficient transfer of point chirality to the supramolecular helical aggregates.U nlike BTAs andO PE-TAs, the chiral amplificationa bility of TPBAs in majority rules experiments shows an egligible dependence on the number of chiralc entersp er monomeric unit, and stands the largest amongt he series of tricarboxamides. Detailed experimental and theoretical studies demonstrate that the rotationa ngle betweent he TPBA units in the helical stack is intermediate to that observed for BTAs and OPE-TAs. This feature strongly conditions the steric interactions between vicinal molecules in the stack and the final chiral amplificationo utcome. Furthermore, theoreticalc alculations show that achiral side chainsf avor the interdigitation of the helical aggregates and thereby the formationof bundle superstructures.
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.
Two series of organic-inorganic composite materials were synthesized through solvothermal imine condensation between diketopyrrolopyrrole dialdehyde <b>DPP-1</b> and 5,10,15,20-tetrakis(4-aminophenyl)porphyrin (<b>TAPP</b>) in the presence of varying amounts of either amino- or carboxylate-functionalized superparamagnetic iron oxide nanoparticles (<b>FeO</b>). Whereas high <b>FeO</b> loading induced cross-linking of the inorganic nanoparticles by amorphous imine polymers, lower <b>FeO</b> content resulted in the formation of crystalline covalent organic framework (COF) 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.
Two series of organic-inorganic composite materials were synthesized through solvothermal imine condensation between diketopyrrolopyrrole dialdehyde <b>DPP-1</b> and 5,10,15,20-tetrakis(4-aminophenyl)porphyrin (<b>TAPP</b>) in the presence of varying amounts of either amino- or carboxylate-functionalized superparamagnetic iron oxide nanoparticles (<b>FeO</b>). Whereas high <b>FeO</b> loading induced cross-linking of the inorganic nanoparticles by amorphous imine polymers, lower <b>FeO</b> content resulted in the formation of crystalline covalent organic framework (COF) 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.
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