Synthesis and characterisation of infinite di- and tri-nuclear zinc co-ordination networks with flexible dipyridyl ligands

Crystallisation of flexible dipyridyl ligands with either Zn(NO3)(2). 6H(2)O or Zn(ClO4)(2). 6H(2)O gave co-ordination networks of composition [Zn-3(OH)(3){(NC5H4)(2)C3H6}(3)][NO3](3). 8.67H(2)O 1 [(NC5H4)(2)C3H6=1,3-bis(4- pyridyl)propane]; [Zn-2(OH){(NC5H4)(2)C4H8}(3)][ClO4](3). H2O . EtOH 2 [(NC5H4)C4H8=1,4-bis(4-pyridyl)butane] and [Zn-2(OH){(NC5H4)(2)C7H14}(4)][ClO4](3). 0.5H(2)O 3 [(NC5H4)(2)C7H14=1,7-bis(4- pyridyl)heptane]. The compounds were characterised by X-ray single crystal diffraction studies. Compound 1 possesses a trinuclear Zn-3(OH)(3) 6-membered ring that acts as a template for the co-ordination framework. Both 2 and 3 possess dinuclear zinc sub-units (Zn2OH) that contain a bridging hydroxyl ion.