Rigid Tether Directed Regioselective Synthesis and Crystallographic Characterization of Labile 1,2,3,4‐Bis(triazolino)[60]fullerene and Its Thermolized Derivatives

Labile bis‐triazoline adducts of C 60 are supposed to be the precursors of bis‐azafulleroids, but the formation mechanism is still unclear because of the incomplete isolation of the thermolized products and the lack of X‐ray structures. A rigid‐tethered reagent 1,2‐bis(azidomethyl)benzene ( 1 ) was used to regioselectively synthesize the labile 1,2,3,4‐bis(triazolino)[60]‐fullerene ( 2 ), the structure of which was determined by single‐crystal X‐ray crystallography. Further thermolysis of 2 produces four products (3 a – 3 d ), which were all characterized by X‐ray crystallography. Although 3 a and 3 b have traditional bis‐azafulleroid structures, as proposed previously, 3 c and 3 d show unprecedented structures with either the coexistence of [5,6]‐open and [6,6]‐closed patterns or an oxidized structure with an 11‐membered ring on the cage. A thermolysis mechanism is proposed to clarify long‐term confusion about the transformation process from bis‐triazoline adducts to bis‐azafulleroids of C 60 .