Synthesis, characterization and crystal structure of a novel europium(III) supramolecular compound: {[Eu(CH3OH)6(H2O)2] [PMo12O40]}· (C14H20O5)2·(CH3OH)2·(CH3CN)2

Polynuclear Molybdenum and Tungsten Complexes containing 3-Hydroxypicolinic Acid and Europium (III)

Novel polynuclear tungsten and molybdenum (VI) complexes with 3-hydroxypicolinic acid (HpicOH) and europium(III) [M4O12Eu(picOH)3] (M(VI) = W, Mo) were prepared by hydrothermal methods. The solid compounds were characterized by FT-IR and FT-Raman spectroscopy and elemental analysis. The photoluminescent properties of the materials were investigated, showing sensitization of the europium(III) luminescence by both the 3- hydroxypicolinate ligand and the polyoxometalate moiety

Novel charge transfer supramolecular assemblies with Keggin anions and 2-amino-5-nitropyridine

Several novel compounds with the non-linear optical chromophore 2-amino-5-nitropyridine (2A5NP) and Keggin polyoxoanions (alpha-isomers), having the general formula (2A5NP)(m)H(n)[XM12O40].xH2O, M = Mo, W, were synthesised. Compounds were obtained with X = P, n = 3, m = 3 and 4 and X = Si, n = m = 4 (x = 2-6). Thus, for each of the anions [PMo12O40]3- and [PW12O40]3- two different compounds were obtained, with the same anion and organic counterpart but with a different stoichiometric ratio. These presented different charge transfer properties and thermal stability. All compounds were characterised by spectroscopic and analytical techniques. The single crystal X-ray diffraction structure of (2A5NP)4H3[PMo12O40].2.5H2O.0.5C2H5OH showed that the water solvent molecules and the organic chromophores are assembled via infinite one-dimensional chains of hydrogen bonds with formation of open channels, which accommodate [PMo12O40]3- and ethanol solvent molecules.

Inclusion of a Cu2+ Ion by a Large-Cavity Crown Ether Dibenzo-24-Crown-8 through Supramolecular Interactions

A supramolecular copper-aqua-crown ether complex, [Cu(II)(H2O)4(dibenzo-24-crown-8]2+ (1c) is stabilized with a Lindqvist-type polyoxometalate anion, [Mo(VI)6O19]2- (1a), in an ion-pair compound [Cu(II)(H2O)4(dibenzo-24-crown-8][Mo(VI6O19] identical with [1c][1a] identical with 1. In the crystal, 1c and 1a assemble to a chainlike structure in which each polyoxoanion 1a is sandwiched by two 1c cations. 1c is a structurally characterized dibenzo-24-crown-8 (a larger-cavity crown ether) supramolecular complex that shows encapsulation of a small cation at the center of its internal cavity, and compound 1 represents a unique example of a first-row transition metal-crown ether inclusion complex that interacts with a polyoxometalate anion.