Antiaromatic Dicyclopenta[]/[]naphthalene Isomers Showing an Open-Shell Singlet Ground State with Tunable Diradical Character.

Since the first isolation of 1,3,5,7-tetra--butyl--indacene in 1986, core-expanded - and -indacenes have attracted intensive interest. However, there is no reported synthesis of such type of molecules due to their high reactivity for over 30 years. Herein, we report the successful synthesis of two relatively stable, core-expanded indacene isomers, dicyclopenta[]-naphthalene () and dicyclopenta[]naphthalene ().

Visualizing designer quantum states in stable macrocycle quantum corrals.

Creating atomically precise quantum architectures with high digital fidelity and desired quantum states is an important goal in a new era of quantum technology. The strategy of creating these quantum nanostructures mainly relies on atom-by-atom, molecule-by-molecule manipulation or molecular assembly through non-covalent interactions, which thus lack sufficient chemical robustness required for on-chip quantum device operation at elevated temperature. Here, we report a bottom-up synthesis of covalently linked organic quantum corrals (OQCs) with atomic precision to induce the formation of topology-controlled quantum resonance states, arising from a collective interference of scattered electron waves inside the quantum nanocavities.

Cyclobis[2,5-(thiophenedimethane)-4,4'-(triphenylamine)] versus Its ,-Dioxidized Macrocycle: Global Antiaromaticity and Intramolecular Dynamics.

Fully conjugated macrocycles containing benzenoid rings rarely show global aromaticity/antiaromaticity. Herein, we report an annulene-like macrocycle and its ,-dioxidized macrocycle with alternative quinoidal thiophene/1,1-dioxide thiophene and triphenyl amine moieties. They both showed temperature-dependent intramolecular dynamics and global antiaromatic character with 32π electrons at low temperature.