Mole-Ratio-Dependent Reversible Transformation between 2:2 and Cyclic 3:6 Silver(I) Complexes with an Argentivorous Molecule

A tetra-armed cyclen (L) with two substituted 3,5-difluorobenzyl and two substituted pyridine-4-yl methyl groups at the 1,4- and 7,10-positions of the cyclen ring as side arms was synthesized. When L was reacted with 1 equiv of the silver(I), dimetallo[3.3]paracyclophane-like 2:2 cyclic dimer, [Ag-2(L)(2)](PF6)(2), was obtained. The reaction of L with 2 equiv of silver(I) gave a 3:6 cyclic trimer, [Ag-6(L)(3)(CH3CN)(3)](OTf)(6)center dot 3CH(3)CN. Furthermore, reversible complexation between the 2:2 cyclic dimer and 3:6 cyclic trimer was confirmed by H-1 NMR and the CSI mass in the addition of silver(I) or the [2.2.2]cryptand.

Automated summary

A tetra-armed cyclen compound (L) was synthesized with various substituents, leading to the formation of a 2:2 cyclic dimer and a 3:6 cyclic trimer upon reaction with silver(I). The reversible complexation between these two structures was confirmed by H-1 NMR and CSI mass analysis.