Tripodal N-donor ligands are used to form halogen-bonded assemblies via structurally analogous Ag+ -complexes. Selective formation of discrete tetrameric I6 L4 and dimeric I3 L2 halonium cages, wherein multiple [N⋅⋅⋅I+ ⋅⋅⋅N] halogen bonds are used in concert, can be achieved by using sterically rigidified cationic tris(1-methyl-1-azonia-4-azabicyclo[2.2.2]octane)-mesitylene ligand, L1(PF6 )3 , and flexible ligand 1,3,5-tris(imidazole-1-ylmethyl)-2,4,6-trimethylbenzene, L2, respectively. The iodonium cages, I6 L14 (PF6 )18 and I3 L22 (PF6 )3 , were obtained through the [N⋅⋅⋅Ag+ ⋅⋅⋅N]→ [N⋅⋅⋅I+ ⋅⋅⋅N] cation exchange reaction between the corresponding Ag6 L14 (PF6 )18 and Ag3 L22 (PF6 )3 coordination cages, prepared as intermediates, and I2 . The synthesized metallo- and halonium cages were studied in solution by NMR, in gas phase by ESI-MS and in the solid-state by single crystal X-ray diffraction.
Keywords: N ligands; X-ray crystallography; cation exchange; halogen bonds; supramolecular chemistry.
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