Ag(I)-based tectons for the construction of helical and meso-helical hydrogen-bonded coordination networks.
The new ligand 4-(3-(2-pyridyl)pyrazol-1-ylmethyl)benzoic acid (L) has been prepared and characterized. This bifunctional ligand incorporates both a chelating region, with two nitrogen donors, suitable for chelating to soft transition metal ions, and a self-complementary hydrogen-bonding region which can facilitate intermolecular association of ligands or ligand-based complexes. X-ray structural analysis of the ligand shows it to adopt a one-dimensional helical polymeric structure, with adjacent ligands hydrogen bonded to each other. Reaction of L with silver(I) salts (AgOTf (1, 1.1.5H(2)O), AgNO(3) (2), AgPF6 (3.CH(3)OH), and AgClO(4) (4.CH(3)OH)) results in the formation of complexes with 2:1 stoichiometries. X-ray structural analysis of these complexes shows that, in each case, one-dimensional chain structures are obtained where chiral AgL(2) tectons are hydrogen bonded together, either directly or mediated by anions or solvent. Structures with either helical or meso-helical structures are observed.
McMorran
David A
DA
Department of Chemistry, University of Otago, P.O. Box 56, Dunedin, New Zealand. davidm@chemistry.otago.ac.nz