Cyclobisintercaland macrocycles: Synthesis and physicochemical properties of macrocyclic polyamines containing two crescent-shaped dibenzophenanthroline subunits

A general access to isomeric dibenzo[bj]phenanthrolinedicarboxaldehydes is described. These pentacyclic planar quinacridine compounds exhibit crescent-shaped forms that fulfill the geometrical requirements of providing broad overlap of nucleobase pairs or triplets. The dialdehyde derivatives have been condensed with various polyamines to give macrocyclic dimeric structures, cyclobisintercalands, of variable size, charge, and shape. The related water-soluble monomeric quinacridines were prepared from the dialdehydes by grafting ammonium groups; The physicochemical properties of the monomeric quinacridines and of the macrocyclic bis-quinacridines have been investigated by spectroscopic methods (UV-vis, fluorescence, NMR). The results show that some of these macrocyclic compounds could exist as semiclosed conformers suitable to accommodate a pair of nucleotides.