title: Tetratopic pyrimidine-hydrazone ligands modified with terminal hydroxymethyl and acryloyl arms and their Pb(II), Zn(II), Cu(II) and Ag(I) complexes.
abstract: The first tetratopic pyrimidine-hydrazone (pym-hyz) molecular strands containing terminal hydroxymethyl (L1) and acryloyl (L2) functional groups have been synthesised. L1 was produced by step-wise imine condensation reactions, starting with 6-hydroxymethyl-2-pyridinecarboxaldehyde. L2 was then synthesised through the treatment of L1 with acryloyl chloride. NMR spectroscopy and X-ray crystallography showed that the ligands adopted a helical shape, comprised of 1 and 1/3 helical turns. Both L1 and L2 uncoiled upon reaction with an excess amount of Pb(II), Zn(II) and Cu(II) ions, resulting in linear M4LA8 complexes (where M = Pb(II), Zn(II), or Cu(II); L = L1 or L2; and A = ClO4(-), SO3CF3(-) or BF4(-)). Horse-shoe shaped Pb2LA4 complexes were also formed by reacting Pb(II) ions with either L1 or L2 in a 2 : 1 metal to ligand ratio. The addition of Ag(I) ions to either L1 or L2 resulted in Ag2L2A2 double helicates, which were stable in the presence of excess Ag(I). The Pb(II), Zn(II) and Ag(I) complexes were characterised by NMR spectroscopy, while UV-Vis spectroscopy was used to probe the Cu(II) complexes. In addition, X-ray crystallography was used to analyse the linear Pb4L1A8, horse-shoe shaped Pb2L1(ClO4)4, twisted Cu3L2(SO3CF3)6, and double helicate Ag2L12(SO3CF3)2 complexes yielding the structures [Pb4L1(ClO4)7(H2O)]ClO4·4CH3NO2 (1), [Pb4L1(SO3CF3)8]2·6CH3CN·H2O (2), [Pb2L1(ClO4)2(CH3CN)(H2O)](ClO4)2·2CH3CN·C4H10O·H2O (3), [Cu3L2(SO3CF3)3(CH3CN)2(H2O)](SO3CF3)3·2CH3CN·H2O (4) and [Ag2L12](SO3CF3)2·CH3CN·H2O (5), respectively.
authors.affiliation: Department of Chemistry, University of Otago, PO Box 56, Dunedin, New Zealand. lhanton@chemistry.otago.ac.nz.
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Hutchinson
authors.forename: Lyall R
authors.initials: LR
authors.lastname: Hanton
authors.forename: Stephen C
authors.initials: SC
authors.lastname: Moratti