The development of highly luminescent two-dimensional covalent organic frameworks (COFs) for sensing applications remains challenging. To suppress commonly observed photoluminescence quenching of COFs, we propose a strategy involving interrupting the intralayer conjugation and interlayer interactions using cyclohexane as the linker unit. By variation of the building block structures, imine-bonded COFs with various topologies and porosities are obtained. Experimental and theoretical analyses of these COFs disclose high crystallinity and large interlayer distances, demonstrating enhanced emission with record-high photoluminescence quantum yields of up to 57% in the solid state. The resulting cyclohexane-linked COF also exhibits excellent sensing performance for the trace recognition of Fe³⁺ ions, explosive and toxic picric acid, and phenyl glyoxylic acid as metabolites. These findings inspire a facile and general strategy to develop highly emissive imine-bonded COFs for detecting various molecules.

Synthetic assembly within living cells represents an innovative way to explore purely chemical tools that can direct and control cellular behaviour. We use a simple and modular platform that is broadly accessible and yet incorporates highly intricate molecular recognition, immolative and rearrangement chemistry. Short bi-modular peptide sequences undergo a programmed sequence of events that can be tailored within the living intracellular environment. Each sequential stage of the pathways beginning with the cellular uptake, intracellular transport and localization imposes distinct structural changes that result in the assembly of fibrillar architectures inside cells. The observation of apoptosis, which is charac-terized by the binding of Annexin V, demonstrates that programmed cell death can be promoted by the peptide assembly. Higher complexity of the assemblies was also achieved by co-assembly of two different sequences, resulting in intrinsi-cally fluorescent architectures. As such, we demonstrate that the in-situ construction of architectures within cells will broaden the community’s perspective towards how structure formation can impact a living system

We have developed a method to solution process strongly hydrogen-bonded odd nylons into ferroelectric thin films.

A common obstacle of many organic semiconductors is that they show highly unipolar charge transport. This unipolarity is caused by trapping of either electrons or holes by extrinsic impurities, such as water or oxygen. For devices that benefit from balanced transport, such as organic light-emitting diodes, organic solar cells and organic ambipolar transistors, the energy levels of the organic semiconductors are ideally situated within an energetic window with a width of 2.5 eV where charge trapping is strongly suppressed. However, for semiconductors with a band gap larger than this window, as used in blue-emitting organic light-emitting diodes, the removal or disabling of charge traps poses a longstanding challenge. Here we demonstrate a molecular strategy where the highest occupied molecular orbital and lowest unoccupied molecular orbital are spatially separated on different parts of the molecules. By tuning their stacking by modification of the chemical structure, the lowest unoccupied molecular orbitals can be spatially protected from impurities that cause electron trapping, increasing the electron current by orders of magnitude. In this way, the trap-free window can be substantially broadened, opening a path towards large band gap organic semiconductors with balanced and trap-free transport.

Solid-state NMR experiments as well as extensive Car–Parrinello Molecular Dynamics simulations are used to study the dependence of supramolecular self-organization of benzene-1,3,5-tricarboxamides (BTA) on the local orientation of the amide functionality. Unlike the known symmetric co-planar helical arrangement of CO-centered BTAs found in supramolecular architectures like supramolecular polymers in gels, N-centered BTAs adopt an asymmetric helical arrangement in the solid-state. The resulting tilt angle between the aromatic cores of neighboring BTA molecules leads to a breaking of the three-fold molecular symmetry and thus causes a splitting of ¹H MAS NMR signals. At elevated temperatures, motional averaging of the split ¹H MAS NMR signals is observed, which can be attributed to certain dynamics on the ms time scale of individual BTA molecules in the columnar packing arrangement.