Chun-Ling Wang

Reactions of trivacant lone-pair-containing tungstobismutate and electrochemical behaviors of its sandwich-type products

We report the crystal structure of dimeric precursor Na12[(Na(H2O)2)6(α-BiW9O33)2] (1), and the interaction of this precursor with transition metal ions. Interaction of 1 with Cu2+ in neutral medium leads to the formation of a Hervé-type sandwich polyoxoanion [(Cu(H2O))3(α-BiW9O33)2]12− (2) in high yield. Interaction of 1 with M2+ (M = Zn, Ni, Co, Mn) in acidic aqueous medium leads to formation of Krebs-type sandwich polyoxoanions [(M(H2O)3)2(WO)2(β-BiW9O33)2]10− (3–6). Coordination geometry of the M2+ ions, counterions and precursors can affect the structure of products. In our experiments, only the interaction of 1 with Cu2+ forms a trisubstituted sandwich-type product. The method using [α-BiIIIW9O33]9− as starting material is a convenient and effective route for the synthesis of sandwich-type tungstobismutates in high purity and yield. The electrochemical properties of these sandwich-type tungstobismutates in aqueous solution are described.

Hydrothermal synthesis, crystal structure and fluorescence of a 3D organic–inorganic hybrid coordination network [CuI(4,4′-bipy)]4[ δ -Mo8O26] exhibiting an interesting polymorphism

A new three-dimensional (3D) extended solid [CuI(4,4′-bipy)]4[δ-Mo8O26] (1) built on {Cu(4,4′-bipy)}+ (bipy = bipyridine) and isopolymolybdate anion [δ-Mo8O26]4− has been synthesized and characterized by elemental analysis, IR, TG, X-ray powder diffraction and single-crystal X-ray diffraction analysis. Compound 1 shows six coppers bonded to [δ-Mo8O26]4− to form inorganic planes which are linked by 4,4′-bipy into a 3D network, the first example of [δ-Mo8O26]4− six-connected linkage based on an organic-inorganic coordination polymer. A polymorphism of compound 1 was found which has an identical molecular formula but absolutely different structure. The influence of the synthesis conditions of 1 has been studied. Furthermore, the fluorescence of 1 is reported.

Synthesis and Structure of a Novel Supramolecular Compound [Co(2,2′-bipy) (H2O)4] [trans-1, 4-chdc] and Separation of Isomer of 1, 4-Cyclohexanedicarboxylic Acid

A supramolecular compound, [Co(2,2′-bipy) (H2O)4] [trans-1, 4-chdc] (compound 1) (2,2′-bipy = 2,2′-bipyridine, 1,4-chdcH2 = 1, 4-cyclohexanedicarboxylic acid), was synthesized and characterized by single-crystal X-ray diffraction analysis, IR spectrometry, TG analysis, and elemental analyses. Single-crystal X-ray diffraction analysis revealed that [Co(2,2′-bipy) (H2O)4]2+ units and adjacent 1, 4-chdc2− formed a single layer by hydrogen bonding and electrostatic interactions along the ac-plane, and two symmetry-related single layers interacted with each other by hydrogen bonding, resulting in a double layer, which further formed a 3-D structure by π-π stacking. The most attractive structural feature of compound 1 is that 1, 4-choc2− possesses only trans-conformation although there are both cis- and trans-conformations in the raw material.