Anion–π and CH···anion interactions in naphthalenediimide-based coordination complexes

Dipyridyl-naphthalenediimide (DPNDI) ligand has been employed to construct a dumbbell-shaped Zn(II)–DPNDI–Zn(II) complex (1) comprised of two solvent-capped trigonal bipyramidal Zn(II) ions and a linear [Zn(II)/DPNDI]_n coordination polymer (2) in which octahedral Zn(II) centres are threaded by axially coordinated DPNDI ligands. X-ray crystal structures of these complexes reveal that charge-diffused counterions bind with the π-acidic DPNDI ligands through anion–π and CH···anion interactions, which in turn play an important role in crystal packing. These insights could be exploited for the sequestration of soft anions through complementary soft–soft interactions with hydrophobic, yet polarisable receptors.