Mimicking cellular phospholipid bilayer packing creates predictable crystalline molecular metal–organophosphonate macrocycles and cages

Evolution of metal–organophosphonates from macrocycles into cages.

Photoluminescent lead(II) coordination polymers stabilised by bifunctional organoarsonate ligands

Four lead(II) coordination polymers were isolated under hydro(solvo)thermal conditions. The applied synthetic methodology takes advantage of the coordination behaviour of a new bifunctional organoarsonate ligand, 4-(1, 2, 4-triazol-4-yl)phenylarsonic acid (H2TPAA) and involves the variation of lead(II) reactants, metal/ligand mole ratios, and solvents. The constitutional composition of the four lead(II) coordination polymers can be formulated as [Pb2(TPAA)(HTPAA)(NO3)]·6H2O (1), [Pb2(TPAA)(HTPAA)2]·DMF·0.5H2O (DMF = N, N-Dimethylformamide) (2), [Pb2Cl2(TPAA)H2O] (3), and [Pb3Cl(TPAA)(HTPAA)2H2O]Cl (4). The compounds were characterized by single-crystal and powder x-ray diffraction techniques, thermogravimetric analyses, infra-red spectroscopy, and elemental analyses. Single-crystal x-ray diffraction reveals that 1 and 2 represent two-dimensional (2D) layered structures whilst 3 and 4 form three-dimensional (3D) frameworks. The structures of 1, 2, and 4 contain one-dimensional (1D) {PbII/AsO3} substructures, while 3 is composed of 2D {PbII/AsO3} arrays. Besides their interesting topologies, 1-4 all exhibit photoluminescence properties in the solid state at room temperature.

Exploring the coordination chemistry of bifunctional organoarsonate ligands: syntheses and characterisation of coordination polymers that contain 4-(1,2,4-triazol-4-yl)phenylarsonic acid

The syntheses, crystal structures, luminescent and magnetic properties of five triazol-phenylarsonic acid-based M(ii) coordination polymers are reported (M = Co, Cu, Mn, Cd).

Silver pyroarsonates obtained from Ag(I)-mediated in situ condensation of aryl arsonate ligands under solvothermal conditions

Four new layered silver(I) organoarsonates, namely, [Ag(3)(L(3))(CN)] (1) (H(2)L(3) = (PhAsO(2)H)(2)O), [Ag(3)(L(4))(CN)] (2) (H(2)L(4) = (2-NO(2)-C(6)H(4)-AsO(2)H)(2)O), [Ag(3)(HL(5))(H(2)L(5))] (3) (H(3)L(5) = 3-NO(2)-4-OH-C(6)H(3)-AsO(3)H(2)) and [Ag(2)(HL(5))] (4), were synthesized under solvothermal conditions. During the preparations of 1 and 2, condensation of organoarsonate ligands (H(2)L(1) = Ph-AsO(3)H(2); H(2)L(2) = 2-NO(2)-C(6)H(4)-AsO(3)H(2)) and the decomposition of acetonitrile molecules to cyanide anions occurred. Single crystals of H(2)L(4) ligand and compounds 1-4 were isolated, and their crystal structures have been determined by single crystal X-ray diffraction studies. In 1, the one-dimensional (1D) chains based on Ag(I) ions and {L(3)}(2-) anions are further interconnected by CN(-) into two-dimensional (2D) layers. In 2, adjacent Ag(I) ions within the silver(I) organoarsonate layer are further bridged by μ(4)-CN(-) anions with very short Ag···Ag contacts. In 3, the hexanuclear {Ag(6)O(12)} clusters are interconnected by bridging organoarsonate ligands into a silver(I) arsonate hybrid layer. In 4, the right-handed {Ag(4)O(4)} chains are further interconnected by organoarsonate ligands as well as additional Ag-O-Ag bridges into a novel silver(I) arsonate layer. Compounds 1 and 2 display red and orange-red emissions, respectively, which may be assigned to be an admixture of ligand-to-metal charge transfer (LMCT) and metal-centered (4d-5s/5p) transitions perturbed by Ag(I)···Ag(I) interactions. Upon cooling from room temperature to 10 K, compound 1 exhibits interesting temperature-dependent emissions.