Metallomacrocycles that incorporate cofacially aligned diimide units

Abstract

Pyromellitic diimide and naphthalene diimide moieties were incorporated into hemilabile phosphanylalkyl thioether ligands. These ligands reacted with [Cu(CH3CN)4]PF6 and [Rh(NBD)Cl]2 (NBD = norbornadiene) by the weak-link approach to form condensed intermediates. Upon reaction of each diimide ligand with these transition-metal precursors, the two diimide units became cofacially aligned within a supramolecular macrocyclic architecture. The introduction of ancillary ligands to each of these condensed intermediates caused the weak thioether-metal bonds to break, thus generating a large macrocycle in which the distance between diimide units is significantly larger than for the condensed intermediates. The two Rh(I) cationic condensed intermediates were characterized by single-crystal X-ray diffraction studies, and the electrochemical activity of these macrocycles was demonstrated with the naphthalene diimide-Cu(I) macrocycles.