Cage Shrinkage of Fullerene via a C₂ Loss: from IPR C₉₀(28)Cl₂₄ to Nonclassical, Heptagon-Containing C₈₈Cl_22/24

A new case of chlorination-promoted fullerene cage shrinkage is reported. Chlorination of C90 (isolated pentagon rule isomer no. 28) with VCl4 afforded C88Cl22 with a nonclassic carbon cage (NCC) containing 1 heptagon and 13 pentagons including 2 fused pairs flanking the heptagon. The pathway of C2 abstraction from the C90 cage is suggested on the basis of density functional theory calculations.本文报道一例由氯化作用诱导的富勒烯笼收缩新案例。以四氯化钒（VCl4）对C90（孤立五边形规则（isolated pentagon rule）异构体编号28）进行氯化反应，合成得到具有非经典碳笼（NCC）的C88Cl22；该碳笼包含1个七元环与13个五元环，其中2个稠合五元环毗邻该七元环。基于密度泛函理论（density functional theory）计算结果，本文提出了从C90笼中脱去C2单元的反应路径。