Intermediate snapshots of a 116-nuclear metallosupramolecular cage-of-cage in a homogeneous single-crystal-to-single-crystal transformation

Soaking crystals of an Au I 72 Cd II 40 Na I 4 cage-of-cage in aqueous Co(NO 3 ) 2 afforded an analogous Au I 72 Co II 44 cage-of-cage, accompanied by the exchange of Na I and Cd II by Co II with retention of the single crystallinity. The homogeneous progress of the transformation led to the direct observation of intermediate species by single-crystal X-ray crystallography. A homogeneous single-crystal-to-single-crystal transformation of an Au I 72 Cd II 40 Na I 4 cage-of-cage to an Au I 72 Co II 44 cage-of-cage, together with the direct observation of intermediate species by single-crystal X-ray crystallography, is reported.