Unexpected formation of 1,2- and 1,4-bismethoxyl Sc₃N@I _h-C₈₀ derivatives via regioselective anion addition: an unambiguous structural identification and mechanism study.

ABSTRACT: An attempt to achieve heterocyclic cycloadducts of Sc₃N@I _h-C₈₀ via reaction with Ph₂C[double bond, length as m-dash]O, PhC[triple bond, length as m-dash]CPh or PhC[triple bond, length as m-dash]N in the presence of tetrabutylammonium hydroxide (TBAOH) stored in CH₃OH led to the formation of the unexpected bismethoxyl adducts of Sc₃N@I _h-C₈₀ (1 and 2). Further studies reveal that TBAOH in CH₃OH can boost the CH₃O^- addition efficiently, regardless of the presence of other reagents. Single-crystal X-ray diffraction results firmly assign the molecular structures of 1 and 2 as respective 1,4- and 1,2-bismethoxyl adducts, and reveal unusual relationships between the internal Sc₃N cluster and the addition modes, in addition to the unusual packing mode in view of the orientation of the methoxyl groups. Electrochemical results demonstrate smaller electrochemical gaps for 1 and 2, relative to that of Sc₃N@I _h-C₈₀, confirming their better electroactive properties. Finally, a plausible reaction mechanism involving anion addition and a radical reaction was proposed, presenting new insights into the highly selective reactions between the methoxyl anion and metallofullerenes. 1 and 2 represent the first examples of methoxyl derivatives of metallofullerenes. This work not only presents a novel and facile strategy for the controllable synthesis of alkoxylated metallofullerene derivatives, but also provides new non-cycloadducts for the potential applications of EMFs.

SUBMITTER: Hu Y 

PROVIDER: S-EPMC8208303 | biostudies-literature | 2021 May

REPOSITORIES: biostudies-literature