Novel inclusion compounds with urea/thiourea/selenourea-anion host lattices

Sonochemical synthesis of two novel Pb(II) 2D metal coordination polymer complexes: New precursor for facile fabrication of lead(II) oxide/bromide micro-nanostructures

Two new lead(II) coordination polymer complexes (CSCs) (2D), [Pb₂(L)₂(Br)₂]_n·H₂O (1), [Pb₂(HL^/)(L^/)(H₂O)₂]_n·H₂O (2), where L = C₆H₅NO₂ (2-pyridinecarboxylic acid) and L^/ = C₉H₆O₆ (1,3,5-tricarboxylic acid), have been synthesized under different experimental conditions. Micrometric crystals (bulk) or microsized materials have been obtained depending on using the branch tube method or sonochemical irradiation. All materials have been characterized by scanning electron microscopy (SEM), powder X-ray diffraction (PXRD) and FT-IR spectroscopy. Single crystal X-ray analyses on complexes 1 and 2 shows that Pb²⁺ ions are 8-coordinated, 7 and 9-coordinated, respectively. Topological analysis shows that the compound 1 and 2 are 4,6L26 and bnn net, respectively. However, neither the shape nor the morphology is maintained, showing the role of sonochemistry to modulate both morphology and dimensions of the resulting crystalline material, independently of whether we have a 2D coordination polymer (CP). Finally, micro structuration of lead(II) bromide oxide and lead(II) oxide have been prepared by calcination of two different lead (II) CPs at 700 °C that were characterized by SEM and XRD.

N-H···S and C-H···S hydrogen bonds in two tetraalkylammonium dithiobiurea(1-) inclusion compounds

Two inclusion compounds of dithiobiurea and tetrapropylammonium and tetrabutylammonium are characterized and reported, namely tetrapropylammonium carbamothioyl(carbamothioylamino)azanide, C12H28N(+)·C2H5N4S2(-), (1), and tetrabutylammonium carbamothioyl(carbamothioylamino)azanide, C16H36N(+)·C2H5N4S2(-), (2). The results show that in (1), the dithiobiurea anion forms a dimer via N-H···N hydrogen bonds and the dimers are connected into wide hydrogen-bonded ribbons. The guest tetrapropylammonium cation changes its character to become the host molecule, generating pseudo-channels containing the aforementioned ribbons by C-H···S contacts, yielding the three-dimensional network structure. In comparison, in (2), the dithiobiurea anions are linked via N-H···S interactions, producing one-dimensional chains which pack to generate two-dimensional hydrogen-bonded layers. These layers accommodate the guest tetrabutylammonium cations, resulting in a sandwich-like layer structure with host-guest C-H···S contacts.

Silver(I) Double and Multiple Salts Containing the 1,3-Butadiynediide Dianion: Coordination Diversity and Assembly with the Supramolecular Synthon Ag4⊂CCCC⊃Ag4

A series of 13 silver(I) double and multiple salts containing 1,3-butadiynediide, C4(2-), were synthesized by dissolving the silver carbide Ag2C4 in a concentrated aqueous solution of one or more of the silver salts AgNO3, AgCF3CO2, AgC2F5CO2, AgF, AgBF4, and AgPF6. The 1,3-butadiynediide anion invariably adopts a mu4,mu4 coordination mode in these compounds, which indicates that the Ag4[cap]C[triple bond]C-C[triple bond]C[cap]Ag4 moiety can be used as a new type of metalloligand supramolecular synthon for the construction of coordination networks. Fine-tuning with various ancillary anionic ligands caused the Ag4 aggregate at each ethynide terminus to adopt a butterfly-shaped, planar, or barblike configuration, within which the silver-ethynide interactions can be classified into three types: sigma, pi, and mixed (sigma,pi). The effect of coexisting nitrile ligands and quaternary ammonium salts on supramolecular assembly with the above synthon was also explored. The hydrolysis of PF6(-) and BF4(-) led to the formation of the quadruple salt Ag2C4 x 4 AgNO3 x AgPF2O2 x Ag3PO4 and a novel (F)2(H2O)18 hydrogen-bonded tape in the triple salt Ag2C4 x 2 AgF x 10 AgC2F5CO2 x CH3CN x 12 H2O, respectively. The largest silver-ethynide cluster aggregate described to date, (C4)3@Ag18, occurs in 3 Ag2C4 x 12 AgC2F5CO2 x 5 [(BnMe3N)C2F5CO2] x 4 H2O (Bn = benzyl).