Crystal structural observation of C4V-symmetric tetrathiahemicarceplexes and their equilibria

The crystal structures of tetrathiahemicarceplexes 1,4-diiodobenzene@1 and 4-iodotoluene@1 are reported. From the crystal structures and 1H NMR experiment the kinetic versus thermodynamic complexation shifts of 4-iodotoluene@1 were observed. The four thia groups of tetrathiahemicarceplex cooperatively built ‘the bottleneck’ leading to the equilibrium shift of carceroisomers.