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.