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.