Indistinguishability and distinguishability between amide and ester moieties in the construction and properties of M6L8 octahedral nanocages

A series of 25 x 25 x 25 angstrom(3) octahedral coordination cages [Pd-6(L)(8)](NO3)(12) (L = L-1, 1; L = L-2, 2; L-1 = tris(6-quinolyl)trimesic ester; L-2 = N,N',N ''-tris(6-quinolyl)-1,3,5-benzenetricarboxamide) is reported. L-1 and L-2 are indistinguishable for construction of octahedral nanocages, and thus the desirable mixed ligand nanocage comprising a statistical ligand distribution ([Pd-6(L-1)(n)(L-2)(8-n)](NO3)(12), 3) can be efficiently constructed. However, the nanocages are distinguishable for functions such as photoluminescence (PL) and catalysis. The PL intensity is in the order 1 >= 3 > 2, wherein 1 shows a blue emission. The nanocages show excellent catalytic activity for the C-C coupling reaction under mild conditions in the order 1 > 3 > 2, presumably owing to the spacer-functional groups.