Solvent-Mediated Central Metals Transformation from a Tetranuclear Ni^II Cage to a Decanuclear Cu^II “Pocket”

When a well-designed tetranuclear Ni^II cage [Ni₄(bppdca)₂(H₂bppdca)₄(SO₄)₂(H₂O)₆]·H₂O·CH₃OH (1; H₂bppdca = N,N′-bis(pyridin-3-yl)-2,6-pyridinedicarbox-amide) was immersed into the methanol solution of CuSO₄, a novel decanuclear Cu^II complex [Cu₁₀(H₂bppdca)₄(SO₄)₈(μ₃OH)₄(CH₃OH)(H₂O)₄]·11H₂O·2CH₃OH (2) would be obtained through central metals transformation. We propose that the transformation is a recurrent dissolving−exchange−crystallization process with a solvent-mediated mechanism confirmed by visual evidence. Direct reaction of H₂bppdca and CuSO₄ in the absence of 1 affords different products.