Solvent-Mediated Central Metals Transformation from a Tetranuclear NiII Cage to a Decanuclear CuII “Pocket”

When a well-designed tetranuclear NiII 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 CuII complex [Cu10(H2bppdca)4(SO4)83OH)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.