Neutral Octa‐Adamantane Chalcogenidometalate Clusters via Amine Complexation and Organotin Termination for Nanolithography

Supertetrahedral chalcogenidometalate clusters, inspired by zinc-blende-type quantum dots, integrate both chemical and geometrical uniqueness. However, their inherent negative charge and rigid T_d symmetry restrict configurational diversity and functional utility. Herein, a synergistic strategy combining polyamine coordination and butyltin termination is employed to synthesize neutral chalcogenidometalate supertetrahedral clusters. Two distinct classes are presented: (1) tetra-adamantane clusters (TA-amine; amine = tris(2-aminoethyl)amine (TAEA), triethylenetetramine (TETA), tetraethylenepentamine (TEPA)) with 14 metal sites and (2) octa-adamantane clusters (OA-X; X═S/Se) with 20 metal sites-the largest neutral supertetrahedral clusters known to date. The OA-X clusters exhibit unprecedented C_2v geometry, deviating from conventional T_d, thereby validating the efficacy of polyamine-arylstannane synergy in advancing cluster chemistry. Charge neutrality and peripheral organic shells confer exceptional solubility and stability in some common solvents, enabling the fabrication of high-quality films for nanopatterning. Electron beam lithography (EBL) reveals that OA-X-based films enable 50 nm line patterning, with the OA-Se version demonstrating the higher sensitivity-a result attributable to the large photoabsorption cross-section of selenium. Solubility-switching behavior is attributed to radiation-induced phase transitions from discrete clusters to chalcogenidometalate nanoparticles. This work bridges molecular precision with functional material design, offering insights into charge-neutral cluster engineering for extreme ultraviolet (EUV) nanolithography.