Helvetica Chimica Acta

Bravetti, Gianluca; Frankberg, Aki; Shahsavan, Mahsa; Zimmermann, Paul; Gallant, Benjamin M.; Konovalov, Oleg; Golobostanfard, Mohammad Reza; Hinderhofer, Alexander; Schreiber, Frank; Kubicki, Dominik J.; Milić, Jovana V.

doi: 10.1002/hlca.202500237pmid: N/A

Metal‐free halide perovskites have recently emerged as promising candidates for optoelectronic applications. However, their synthesis has largely depended on water‐based single‐crystal growth that limits material diversity, scalability, and practical implementation. Here, we present a mechanochemical route to synthesize N,N‐diazabicyclo[2.2.2]octonium (H‐DABCO)‐based halide perovskites from the (DABCO)(NH4)X3 (X = I, Br) compositions. The structural properties were confirmed by X‐ray diffraction and solid‐state nuclear magnetic resonance spectroscopy. Thin films were prepared from mechanosynthetic powders by spin‐coating and characterized by in‐situ grazing incidence wide‐angle scattering measurements, as well as by UV–vis absorption and steady‐state photoluminescence spectroscopy. This mechanosynthetic strategy provides a scalable, environmentally friendly pathway to broaden the scope of metal‐free perovskites and advance their potential in sustainable optoelectronic technologies.

Belrhomari, Sophia; Hevia, Eva

doi: 10.1002/hlca.70082pmid: N/A

Advancing the synthetic and constitutional knowledge of alkali‐metal amides, here we report the synthesis and structural authentication of a family of alkali‐metal N‐phenyl‐1‐naphthylamides (1Li, 1Na, and 1K) obtained from the deprotonation of the parent amine by an alkali‐metal alkyl base in hexane and using biorenewable 2‐methyltetrahydrofuran (2‐MeTHF) as a Lewis donor. The aggregation and degree of donor‐solvation of these complexes differ depending on the nature of the alkali‐metal. Furthermore, the lithium N‐phenyl‐1‐naphthylamide complex 1Li can undergo further metalation on the peri position of the naphthyl ring using either nBuLi or nBuNa as a base to give complexes 2LiLi, and 2LiNa, respectively. X‐ray crystallographic studies established the molecular structures of these complexes in which both alkali‐metals are chelated by a novel C,N‐dianionic bidentate ligand. Quenching of 2LiLi, and 2LiNa with D2O provided further evidence supporting that the NH, C(peri)‐H di‐metalation has occurred.

Clough, Jess M.

doi: 10.1002/hlca.70080pmid: N/A

In many of their applications, polymeric materials are expected to withstand mechanical loads, yet the molecular‐scale processes that govern how stress localizes, redistributes, and ultimately leads to damage remain difficult to probe directly. Mechanophore‐based mechanochromic systems offer a powerful approach to address this challenge by converting mechanical input into optical signals detectable with spectroscopic and microscopic techniques. In this Perspective, we highlight recent progress in the use of mechanophores as probes for imaging mechanical processes in solid‐state polymers. We discuss how mechanophore activation can reveal molecular damage, stress localization, and time‐dependent deformation processes, and how emerging reversible and multiplexed, or multimodal systems extend mechano‐imaging to lower stress regimes. Finally, we outline key challenges for the field, including the development of new mechanophore scaffolds for quantitative mechano‐imaging and scalable reporter systems suitable for real materials and structural health monitoring. Together, these advances position mechanophore‐based mechano‐imaging as a promising framework for interrogating and ultimately controlling the distribution and dissipation of mechanical energy in polymeric materials.

Moreno, Julia; Ren, Xudong; Saidjalolov, Saidbakhrom; Josso, Pierre; Sakai, Naomi; Matile, Stefan

doi: 10.1002/hlca.70081pmid: N/A

This study elaborates on traceless tags for the thiol‐mediated uptake (TMU) of amine‐containing substrates of interest (SOIs). Traceless tags typically contain linkers that can be enzymatically cleaved to trigger the release of SOIs in their native form. To trace SOI release inside cells, the dual function of asparagusic acid (AspA) derivatives to enable TMU and to track the Golgi apparatus is explored. We tested two of the most popular cleavable linkers based on esterases and quinone reductases. Conjugated to AspA through alkyloxycarbonyloxymethyl (AOCOM) linkers, fluorescent SOIs entered cells by TMU and spread in the cytosol with or without a brief stop in the Golgi, depending on the structure. FRET probes further demonstrated that after arrival in the Golgi, SOIs are released from AspA into the lumen, where they linger before spreading to the cytosol and beyond. Quinone‐based trimethyl locks (TML) are also compatible with TMU, but reductive cleavage after TMU appears to be slower in the Golgi. These results validate AOCOM and TML linkers for constructing traceless TMU tags for amine‐containing SOIs and introduce AspA probes as dynamic‐covalent chemistry tools to trace traceless tags inside cells and to track Golgi lumen and Golgi membranes simultaneously with separately visualizable fluorescent probes.