KINETIC AND THERMODYNAMIC EFFECTS IN THE SELF-ASSEMBLY OF [3]CATENANES IN THE SOLUTION AND SOLID STATES

A change in the constitution of the tetracationic cyclophane component s (comprised of two paraquat residues bridged by either m-or p-phenyle ne rings) in [2]catenanes, where the other macrocyclic components are polyethers (incorporating two pi-electron-rich rings, such as 1,4-diox ybenzene or 1,5-dioxynaphthalene, located symmetrically within a crown -10 structure) not only affects the efficiencies but also the selectiv ities associated with the self-assembly processes that lead to the for mation of inlerlocked molecular compounds. The self-assembly of two ne w [2]catenanes-composed of cyclo-(paraquat-p-phenylene-paraquat-m-phen ylene) and either 1,5-dinaphtho-38-crown-10 (1/5DN38C10) or 1,5-naphth o-p-phenylene-36-crown-10 (1/5NPP36C10) - is accompanied by the format ion, in each case, of a [3]catenane incorporating a dimer of the tetra cationic cyclophane and one or other of the two macrocyclic polyethers . A mechanistic rationale, based on thermodynamic and kinetic consider ations, is presented to explain the formation of the dimeric octacatio nic products. The Xray crystal structures of the two [3]cat enanes rev eal the dominance of pi-pi stacking interactions both within the molec ules and beyond them where highly distinctive brick-like and parquet-l ike packing motifs are observed.