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Two new ligands 4,6-bis(4′-pyridylsulfide)dibenzofuran L1 and 4,6-bis(methylsulfanylmethyl)dibenzofuran L2, based on dibenzofuran with exodentate thio-pyridine arms were prepared. The crystal structures of three metallomacrocycles were determined. Reaction of L1 with AgClO4 in a 1 : 1 metal-to-ligand ratio gave a ClO4− clamped metallomacrocycle, 1. The analogous reaction with CuCl2 gave a metallomacrocycle, 2, in which bridging chloride ions bisected the macrocycle. Both metallomacrocycles were rectangular in shape but their cavities were occluded by bridging interactions. Reaction of L2 with CuI in a 1 : 2 metal-to-ligand ratio gave a metallomacrocycle, 3, in which Cu2I2 moieties were incorporated into the edge of the macrocycle. This allowed for clearly defined cavities, which formed channels containing MeCN molecules in the overall three-dimensional honeycomb array.

The ligand bis(2-pyridylmethyl)sulfide L′ and the complexes it formed were used as simple probes for the complexes of 2,5-bis(2-pyridylmethylsufanylmethyl)pyrazine L. L′ and L were reacted in 1 ∶ 1 and 1 ∶ 2 molar ratios, respectively, with both CuCl2 and CuI. Crystal structures of all four complexes were determined, CuCl2L′·H2O (1), Cu2Cl4L (2), Cu2I2L′2 (3) and [Cu2I2L]∞ (4). The Cu(II) ions in 1 and 2 were square pyramidal. For 2 crystal structures of the anti (2a) and the syn (2b) isomers were determined and both were found to form proto-polymeric chains. Complex 3 was dimeric and contained Cu2I2 bridges. The structure of 4 revealed one-dimensional polymeric chains in which the ligands were joined by Cu2I2 bridges. This work demonstrated the successful use of the complexes of L′ as probes for 4 and to a lesser extent for 2a and 2b.

In order to investigate the effect of methyl group substitution adjacent to a pyridyl N donor, three ligands were synthesised and complexed with CuI in a 1 ∶ 2 ratio. The crystal structures of three CuI complexes were determined. The dimethylated ligand bis(6-methyl-2-pyridylmethyl)sulfide (L1) gave rise to a tetranuclear complex with two Cu2I2 bridges in which the Cu centres were four-coordinate. The asymmetric ligand 2-(6-methylpyridyl)methyl(2-pyridyl)methylsulfide (L2) gave a tetranuclear complex which contained two parallel Cu2I2 bridges. In each Cu2I2 bridge, one Cu centre was three- and the other four-coordinate. In contrast, the ligand bis(2-pyridylmethyl)sulfide (L3), with no Me substitution, gave rise to a one-dimensional coordination polymer with CuI chains. It was found that the differences in the complexes were a result of both the electronic and steric effects arising from the Me substitution of the pyridine donors and that no one effect completely dominated.

The ligand 2,5-bis(2-pyridylmethylsulfanylmethyl)pyrazine (L) was prepared by the base coupling of 2-(sulfanylmethyl)pyridine and 2,5-bis(chloromethyl)pyrazine. This new ligand was treated with AgClO4 in a 1 ∶ 1 metal-to-ligand ratio and with AgNO3 in a 2 ∶ 1 metal-to-ligand ratio to give coordination polymers. The crystal structures of {[Ag(L)]ClO4}∞ (1) and {[Ag2(L)](NO3)2}∞ (2) were determined. The Ag(I) ions in the one-dimensional polymeric chains of 1 adopted square-pyramidal geometries with the pyridine and pyrazine N donors coordinated in an extremely bent fashion. The structure of 2 revealed two isomeric polymer chains in the one crystal forming a single supramolecular array. The isomeric polymers differed in the donor atoms about the Ag(I) ions and in the arrangement of adjacent ligands along the chain. A feature of both structures was that L adopted a three-layer π-stacked arrangement.

The ligands 1,4-bis(2-pyridylmethylsulfanylmethyl)benzene (L1) and 2,5-bis(2-pyridylmethylsulfanylmethyl)pyrazine (L2) were treated with Cd(NO3)2.4H2O in metal-to-ligand ratios of 1:1 and 2:1, respectively; L2 was also treated with CdCl2.2.5H2O in a 2:1 ratio. All products were found to be coordination polymers. The crystal structures of {[Cd(L1)(NO3)2].CH2Cl2}infinity (1a), {[Cd(L1)(NO3)2].4/3CH3CN}infinity (1b), {[Cd2(L2)(NO3)4].2CH3CN}infinity (2.2CH3CN), and {[Cd2(L2)Cl4].2CH2Cl2}infinity (3.2CH2Cl2) were determined. Compounds 1a and 1b were found to be conformational supramolecular isomers. The structure of 1b displayed topological isomerism with two isomeric polymer chains, 1b(1) and 1b(2), in the one crystal forming a single supramolecular array. The structure of 2.2CH(3)CN showed Cd2(L2) units linked together by nitrates bridging between the Cd(II) centers in a mode previously not seen in Cd(II) compounds. The overall structure of 3.2CH2Cl2 was found to be similar to that of 2.2CH3CN despite the presence of different anions and solvent molecules. Powder X-ray diffraction was used to investigate the nature of bulk preparations of compounds 1-3.

In-situ planar chirality was induced in an achiral ligand by intramolecular π-stacking interactions upon complexation with silver(I) and crystallisation, to give a single-stranded helix with a nanoscale pitch which assembled into a three-dimensional network.

Reactions of tri- and penta-dentate thio-substituted oligopyridines with Ag(I) yielded two differently coded bi- and tri-nuclear structures containing strong intraligand π stacking of the heterocycles.