The ethanol–water layered syntheses and crystal structures of the coordination polymers [Cd(C17H22N2)2(H2O)2]·2(ClO4)·C17H22N2·C2H5OH 2 and [Cd(C17H22N2)2(NO3)2] 3 are reported, where C17H22N2 is a flexible spacer, 1,7-bis(4-pyridyl)heptane. In compound 2, trans-CdO2N4 octahedral nodes are linked by pairs of bridging ligands to result in [001] looped polymeric chains. The chains stack in the [100] direction to form (010) pseudo layers. Sandwiched between them are secondary sheets of free ligands, perchlorate ions and ethanol solvent molecules. Hydrogen bonds between these species help to consolidate the structure. Compound 3 contains trans-CdO2N4 octahedral nodes as parts of regular 44 nets, which propagate in the (103) plane. Three independent nets are interpenetrated.

The crystallisation of different copper(II) salts with the new ligand 1,3-bis[2-(4-pyridyl)ethyl]-benzene, C20H20N2 (L) are reported. The anion is incorporated into each structure, but it plays a completely different role in each case: a novel ‘paddlewheel’ cluster with the nitrate ion, infinite sheets with the acetate ion and chains with the sulphate ion.

The syntheses and structures of the coordination polymers [Cd(ppeb)2(H2O)2]n·(NO3)2n (1), [Cd(ppeb)2(ClO4)2]n (2), [Cd(opeb)2(NO3)2]n (3), and [Cd(opeb)2(H2O)2]n·(ClO4)2n (4), where ppeb and opeb represent the 1,4- and 1,2-isomers of bis[2-(3-pyridyl)ethyl]-benzene, C20H20N2, respectively, are described. Each structure contains trans-CdO2N4 octahedra. In 1 and 2, they are bridged by pairs of ligands to generate looped chains, whereas in 3 and 4 the ligands link the metal nodes into squashed 44 polymeric sheets. In 1 and 4, O–H…O hydrogen bonds from the coordinated water molecules to the uncoordinated anions help to consolidate the structures.

Two receptors are described which are designed to complex barbiturates and cyanuric acids. The functional groups at the binding pocket are polar and are designed to enable guest exchange from water to occur by a dispersion of the host. One receptor has a charged binding pocket lined with two phosphate groups resembling a surfactant. Evidence for the partial extraction of diethylbarbituric acid from water is presented. The more polar guest sodium alloxan 5-f-sulfonatophenylhydrazone was not complexed. The receptors were both used to solubilise two insoluble bis-isocyanuric acids by forming 2:1 complexes in chloroform.

The reactions of Cu(NO3)(2), Co(NO3)(2) and Ni(NO3)(2) with bp_ pen = 1,5-bis(4-pyridyl) pentane yield three-dimensional coordination polymers [M(bp_ pen) 2(NO3) 2] with M = Cu (1), Co (2), Ni (3). These are four-connected uninodal 3D nets exhibiting a rare (6(5).8) topology defined by metal centres (nodes) and bipyridyl ligands (edges). The reaction of CuNO3 with bp_ hep = (1,7-bis(4pyridyl) heptane yielded a similar net in the structure of [Cu-2(bp_ hep)(4)(NO3)(3)](NO3)(H2O) (4). A characteristic of the networks of 1-4 is that their shortest edge is by far (50%) longer than the shortest distance between two neighbouring nodes. This unusual geometrical feature is facilitated by the long and flexible bp_ pen and bp_ hep spacers. All four investigated crystal structures are composed of three interpenetrating (6(5).8) nets.

Three distinct 2-D coordination networks with (4,4) topology where obtained from solutions containing a chiral ligand L and the appropriate metal salt, [CdL2(NO3)2](n)center dot H2O where L = (R, R)-, (S, S)- and (R, S)-1,4-bis[2-(4-pyridyl)-2-methyl)ethyl] benzene (0.25 : 0.25 : 0.5), [CdL2(H2O)(2)](n)center dot L'center dot(H2O)(2)center dot(ClO4)(2) where L = (R, R)-, (S, S)- and (R, S)-1,4-bis[2-(4-pyridyl)-2-methyl)ethyl] benzene (0.25 : 0.25 : 0.5) and [ML2(H2O)(2)](n)center dot L center dot(NO3)(2) where M = Co or Ni and L = (R, S)-1,4-bis[2-(4-pyridyl)-2-methyl)ethyl]benzene). These nets display different geometrical features including different modes of connection of L units by the four-connected metal centre. In addition, the infinite chain structure [CdL2(NO3)(2)](n)center dot H2O where L = (R, S)-1,3-bis[2-(4-pyridyl)-2-methyl)-ethyl] benzene whose metal centres are also four-connected and the finite molecular structure [CuL2(NO3)(2)]center dot H2O with L = 1,4-bis[2-(3-pyridyl)-2-methyl-cis-ethenyl)]benzene) were obtained.

N,N-Bis-(3-pyridylmethyl)succinamide and Cu(ClO4)2 crystallise to give infinite helical strands.

Lead(II) carboxylate soaps of two fatty acids, palmitic (C15H31COOH) and stearic acids (C17H35COOH), and a dicarboxylic acid, azelaic acid (HOOCC7H14COOH), have been synthesised and characterised by FTIR spectroscopy. These acids are all encountered in aged traditional oil paint, the azelaic acid resulting from the oxidative degradation of unsaturated fatty acids in the oil. Lead(II) azelate synthesised by hydrothermal methods was characterised by single crystal structure determination. This has a 3D polymeric structure with lead(II) ions linked by carboxylate bridges to form an infinite stack of (PbO4)n units. These layers are connected to adjacent layers by an infinite number of parallel C(CH2)7C chains arranged perpendicularly to the stacks. The lead(II) ions display an unusual 7-fold coordination. The first direct evidence that the ‘protrusions’ encountered in aged traditional lead-containing oil paints contain lead soaps is reported. Their mechanism of formation is discussed.