Modification of supramolecular motifs: some effects of incorporation of metal complexes into supramolecular arrays

Abstract

The structures of four supramolecular arrays incorporating concerted triple acceptor–donor–acceptor/donor–acceptor–donor (ADA/DAD) hydrogen bonds are described. The first is comprised of 1 ∶ 1 phthalimide ∶ 2,4-diamino-6-phenyl-1,3,5-triazine units linked into a one-dimensional strand by more loosely connected independent interposed triazine moieties. The second, composed of [bis(dithiobiureto)nickel(II)∶(3-iminoisoindolinone)₂] units, incorporates similar complementary triplet hydrogen bonding motifs. The third system involves a 1 ∶ 2 assembly between the dianionic complex, bis(biureto)nickelate(II) and 2,4-diamino-6-phenyl-1,3,5-triazine to yield the bis(tetraethylammonium) salt of the [bis(biureto)nickelate(II)∶(2,4-diamino-6-phenyl-1,3,5-triazine)₂] dianion unit, the array again extended by secondary interactions. The final assembly investigated is composed of ‘tri-component’ units of type [bis(biguanidino)nickelate(II)∶(6,7-dimethoxy-2,4(1H, 3H)-quinazolinedione)₂] that feature an excess of hydrogen bond donor groups over acceptor groups. As in the above assemblies, it also incorporates hydrogen bonds between complementary triplet motifs as well as bridging hydrogen bonds between individual units. This last assembly is no longer planar; in the lattice being linked into a two dimensional network by dimethylsulfoxide molecules that act as ‘ancillary’ acceptors for the excess donors present and also as bridging molecules between neighbouring tri-component units. The hydrogen bond geometries in these assemblies are discussed comparatively and also compared with related arrays reported in the literature.