3He@C60 as a Concise Probe in Complex Systems: Diels‐Alder Reac‐tions of Fullerene with Different Bis Anthracene Compounds.

Three bis‐anthracene (BA) compounds, characterized by varying alkyl chain lengths between the two anthracene groups, were synthesized and investigated using 3He NMR spectroscopy on He@C60 derivatives. The Diels‐Alder reaction of these BAs with fullerene was comprehensively explored. Findings disclosed that BAs with shorter linkers formed mono‐adducts with 3He@C60 at lower concentrations. Conversely, the BA compound with the longest linker (1 c) yielded both mono‐adducts and bis‐para‐adducts with C60, marked by a distinct 3He NMR signal peak for bis‐adducts at −12.84 ppm. Importantly, the versatility of the 3He@C60 probe was exemplified in characterizing intricate fullerene reactions that conventionally pose challenges. Theoretical analyses validated reaction products, with computational models substantiating experimental results. [ABSTRACT FROM AUTHOR]