Coordination Assembly, Multidimensional Structures And Properties Of Lanthanide, Atkaline-earth Containing Tungstobismuthate Coordination Compounds

Thirteen new compounds based on tungstobismuthates and lanthanide cations,alkaline-earth metal cations have been synthesized via conventional method. Thesecompounds were structurally characterized by IR, UV-Vis, elemental analyses, TG and singlecrystal X-ray diffractions. The photoluminescence, magnetic property and surfacephotovoltage property of the compounds have been discussed.1. The reaction of Na12[Bi₂W₂₂O₇₄（OH）₂]·44H₂O(abbr.{Bi₂W₂₂}),Na₉[BiW₉O₃₃]·16H₂O （abbr.{BiW₉}）, lanthanide chloride(Pr_<sup>3+，Nd³⁺，La³⁺å'ŒCe³⁺) andNa₂CO₃in aqueous solution resulted in the four unprecedented giantlanthanide-tungstobismuthate compounds1-4.Na₂₂[(BiW₉O₃₃)₄（WO₃）{Bi₆（3-O）₄（2-OH）3}（Pr₃（H₂O）6CO₃）]·95H₂O （1）Na₂₂[(BiW₉O₃₃)₄（WO₃）{Bi₆（3-O）₄（2-OH）3}（Nd3（H₂O）6CO₃）]·91H₂O （2）Na₂0H₂[(BiW₉O₃₃)₄（WO₃）{Bi₆（3-O）₄（2-OH）3}（La3（H₂O）6CO₃）]·73H₂O （3）Na₂₂[(BiW₉O₃₃)₄（WO₃）{Bi₆（3-O）₄（2-OH）3}（Ce3（H₂O）6CO₃）]·85H₂O （4）The result of Single-crystal X-ray diffraction analysis reveals that the polyanions of thefour complexes are isomorphic. A trigonal arrangement of three lacunary a-B-{BiW₉}fragments is linked by one [{Ln+3（H₂O）6CO₃}]7+{Ln=Pr_<sup>3+（1）, Nd3（2）, La³⁺（3）, Ce³⁺（4）}unit. This assembly is connected to the fourth a-B-{BiW₉} fragment by means of one[{Bi₆（3-O）₄（72-OH）3}]+polyoxo cation and one additional six-coordinate tungsten atom.The luminescent property of1was characterized. This result suggests that the compound1may be a good candidate for fluorescent materials. Magnetic investigation revealed that theweak antiferromagnetic interaction between the neighboring metal centres are responsible forthe magnetic properties of1and2.2. The reaction of {Bi₂W₂₂},{BiW₉} and ErCl3in aqueous solution resulted in acompound5:Na_4.5H_5.5[Bi₂W₂₁Er（H₂O）3（OH）]·40H₂O （5）A centrosymmertric dimer in the compound5is built from two[Bi₂W₂₁O72Er（H₂O）3（OH）]10-fragments by means of two Er–O–W link, The dimer is leadedto the formation of a2D network connected by Na anions. The magnetic investigation on5reveal weak antiferromagnetic interactions between the magnetic centers.3. Four all-inorganic multidimensional polyoxometalate compounds6-9based on theparadodecatungstate-B anions [H₂W₁₂O₄₂]10-and alkaline-earth metal have been isolated bythe reaction of {Bi₂W₂₂},{BiW₉}, and alkaline-earth metal ions(Ca²⁺, Sr²⁺and Ba²⁺) inaqueous solution.Ca2Na6[H₂W₁₂O₄₂]·30H₂O （6） Sr₄H₂[H₂W₁₂O₄₂]·26H₂O （7）Sr₄Na₂[H₂W₁₂O₄₂]·30H₂O （8）Ba₄Na₂[H₂W₁₂O₄₂]·29.5H₂O （9）The starting materials of {Bi₂W₂₂} precursor play an important role in the synthesisreaction, in which the [H₂W₁₂O₄₂]^10-anion slowly arose from {Bi₂W₂₂} precursor so as toavoid the formation of precipitation. The compound7represents the first example of3Dall-inorganic frameworks in which the paradodecatungstate-B [H12W₁₂O₄₂]^10-anions werelinked by only alkaline-earth metal cations. The surface photovoltage spectra （SPS） andelectric field-induced surface photovoltage spectra （EFISPS） demonstrate that compounds6–9should be of p-type semiconductors, suggesting the possibility to become new photocatalysisand light-to-electricity conversion materials. The reflectance spectra of the compounds6-9reveal the nature of semiconductivities with a large energy gap for compounds1–4. the PLspectra of compounds6–9are very similar to CaWO₄, SrWO₄and BaWO₄, suggesting thatcompounds6–9may find application like CaWO₄in laser and fluorescent materials.4.The reaction of Na₁₀[Bi₂W₂₀Co₂O₇0（H₂O）₆]·41H₂O(abbr.{Bi₂W₂₀Co₂}),{BiW9},alkaline-earth metal ions(Ca²⁺, Sr²⁺and Ba²⁺) in aqueous solution at resulted in the fourmultidimensional polyoxometalate compounds10-13based on the {Bi₂W₂₀Co₂} andalkaline-earth metalCa2Na₂H₄[Bi₂W₂₀Co₂O₇₀]·37H₂O （10）,Sr₄Na₂[Bi₂W₂₀Co₂O₇₀]·36H₂O （11）,Sr₃H₄[Bi₂W₂₀Co₂O₇₀]·57.5H₂O （12）Ba₄H₂[Bi₂W₂₀Co₂O₇₀]·45.5H₂O （13）When the {Bi₂W₂₂} precursor was replaced by {Bi₂W₂₂Co₂} with the similar synthesisroutine, decomposition process in the reaction did not happen. The compound13representsthe first example of polyanions coordinating Ba cations with the unprecedented3D networkstructure. The magnetic investigation of10-13indicate the presence of an antiferromagneticinteraction between the neighboring magnetic centers.