A trigonal prismatic ligand in the metal-mediated self-assembly of one- and two-dimensional metallosupramolecular polymers.

A novel trispyrazine-pillared prismatic bicycooxacalixaromatic ligand L is synthesized, and its application in metal-mediated self-assembly is described. Under self-assembly conditions, single chain, double-stranded cross-linked coordination polymer and two-dimensional (2D) coordination polymeric networks were formed via M-L (Ag(+), Cu(2+), and Zn(2+)) coordinative interactions. Structural analyses revealed that the antiparallelly arranged one-dimensional coordination polymers (Cu(2+) and Zn(2+)) are arranged to generate well-defined voids to host aromatic guests (benzene) via C-H···π and π···π interactions, while the double-stranded cross-linked coordination polymer (Ag(+)) contains a rhomboidal [Ag2(L(3))2] (L(3): tridentate ligand) cage motif to include a benzene guest; the "thicker" (thickness: ac 5 Å) 2D coordination polymeric networks (Ag(+), Cu(2+), and Zn(2+)), however, are all formed by connection of one or two kinds of topologically different metallomacrocyclic cage units. These unique metallomacrocyclic cage units in the 2D coordination polymeric networks are capable of hosting different guest species. For instance, the rhomboidal [M2(L(3))2] (M = Ag(+), Cu(2+)) cage units were found to host a benzene or a nitrate anion; a hexahedral [M3(L(3))3] (M = Ag(+)) cage was found to host a ligand L or a DMF molecule; the hexahedral [M4(L(3))4] (M = Cu(2+)) cage was found to host four solvent molecules of benzene; and the rectangular [M3(L(3))3] (M = Cu(2+), Zn(2+)) cage units, however, were found to host two THF molecules. The results highlight the potential of ligand L for applications in the construction of "thicker" 2D coordination polymeric networks with well-defined metallomacrocyclic cage units capable of hosting various guest species.

Coordination-driven self-assembly of discrete and polymeric copper(ii) and dicopper(ii) supramolecular structures based on oxacalix[2]benzene[2]pyrazines.

The reaction of oxacalix[2]benzene[2]pyrazines and with copper(ii) nitrate, as well as dimeric copper(ii) tetraacetate are presented. Ligands and , both adopt 1,3-alternate conformation, with the two exo-Lewis basic sites spatially oriented outwards. Ligand reacts with copper(ii) ions generated a discrete molecular cage by bridging two ligands via two Cu(2+) ions in the equatorial region. While the reaction of with dicopper(ii) tetraacetate unit resulted in the formation of a discrete supramolecular complex with 1 : 2 stoichiometry between the dicopper(ii) unit and ligand , due to the larger size and axial coordination mode of the dicopper(ii) unit. The conformationally flexible nature of ligand facilitated the formation of coordination polymers and upon interaction with copper(ii) and dicopper(ii) units, respectively. Coordination polymer featured a zigzag structure of alternating ligand and Cu(2+) ion, while in coordination polymer , ligand serves as an axial 2-connected node, propagating the "paddlewheel" dicopper(ii) unit along the polymeric chain.