Tailoring Titanium Carbide Clusters for New Materials: from Met-Cars to Carbon-Doped Superatoms.

Tailoring materials with prescribed properties and regular structures is a critical and challenging research topic. Early transition metals were found to form supermagic MC metallocarbohedrenes (Met-Cars); however, stable metal carbides are not limited to this common stoichiometry. Utilizing self-developed deep-ultraviolet laser ionization mass spectrometry, here, we report a strategy to generate new titanium carbides by reacting pure Ti clusters with acetylene. Interestingly, two products corresponding to TiC and TiC exhibit superior abundances in addition to the TiC Met-Cars. Using global-minimum search, the structures of TiC and TiC are determined to be an ellipsoidal D and a rod-shaped D geometry, respectively, both with carbon-capped TiC moieties and superatomic features. We illustrate the electronic structures and bonding nature in these carbon-doped superatoms concerning their enhanced stability and local aromaticity, shedding light on a new class of metal-carbide nanomaterials with atomic precision.