Coordination-Triggered Disassembly of Robust Two-Dimensional Fullerene Frameworks via Intercage C─C σ-Bond Scission.

Two-dimensional fullerene frameworks such as Mg4C60 and its metal-free derivative 2D-C60 are densely cross-linked all-carbon lattices, in which each C60 cage is tethered to six neighbors through eight intercage C─C σ-bonds. Formed under high-temperature conditions (ca. 500°C-600°C), these junction-rich architectures are generally resistant to post-synthetic lattice editing or recovery of intact fullerene building blocks. However, we show here that mild transition-metal coordination can unlock these frameworks under mild solution conditions by cleaving covalent intercage C─C bonds. Treating Mg4C60 with W(CO)4(Ph2PCH2)2 leads to measurable depolymerization and time-dependent formation of molecular C60. NiCl2(PMe3)2 promotes substantially more efficient cleavage and enables direct detection of a cleavage intermediate (m/z = 899), supporting coordination-linked bond-scission pathway. Density functional theory shows that C60-M-C60 bridge formation increases the exothermicity for intercage C─C bond scission, and rationalizes the stronger thermodynamic driving force for Ni-catalytic system relative to W-catalytic system. Furthermore, Mg2+ removal markedly suppresses depolymerization, indicating that Mg intercalation promotes junction opening through MgCl2 formation and charge-state modulation. These results establish coordination-triggered intercage bond cleavage as a strategy for lattice editing and programmable disassembly in carbon-rich 2D frameworks.