Design And Synthesis Of New Polyoxometalates Based On {X^â…¢W₉O₃₃}（X=Sb, Bi） Building Blocks

Four new polyoxometalates （POMs） based on trivacant polyoxoanions [XIIIW9O33]（X=Sb, Bi） building blocks have been synthesized by conventional solution synthetic methodsaccording to the one-pot and step-by-step synthetic strategies. All these compounds have beencharacterized by IR, elemental analysis, TG, and single crystal X-ray diffraction. Furthermore,photocatalytic and electrochemical properties were also investigated.1. Two new one-dimensional chainlike poly（POMs） were synthesized according to theone-pot synthetic strategy with the molecular formula as follows:Na_8.8[W_0.3Mn_3.7（H₂O）₈(B-β-BiW₉O₃₃)₂]·25H₂O（1）Na_8.4[W_0.4Co_3.6（H₂O）₁₀(B-β-BiW₉O₃₃)₂]·33.5H₂O （2）In compounds1and2, the trivacant [B-β-BiW9O33]9-polyoxoanions are combined withtransition metal ions （Mn2+and Co2+, respectively）, forming the basic sandwich-type buildingunits. Then, these sandwich-type units are linked together via the coordination bonds betweenTM ions and surface O atoms of POMs, constructing the infinite1-D inorganic chain. Bothcompounds exhibit catalytic activities for photo degradation of RhB.2. According to the step-by-step strategy, two new Ln-substituting POMs decorated byorganic ligands were obtained based on the assembly system that contains trivacant POMunits [B-β-SbW9O33]9-, organic ligands and Ln ions in aqueous solution. The molecularformula of compounds3and4are as follows:Na₁₀[La₂（H₂O）₄（WO₂（pic））₂(SbW₈O₃₀)2]·28H₂O （3）K₄Na₉Li₁₁[（Dy（H₂O））(SbW₈O₃₁)（WO₃）（Sb₃O₃）（Dy（pic））(SbW₉O₃₃)]₂·23H₂O （4）Compound3contains in situ generated {SbW₈O₃₀} tetravacant polyoxoanion units,which are linked by two {WO₂（pic）} linkers and two hydrated La ions, forming new helicalchain. Furthermore, these adjacent helical chains are stacked into three-dimensional openframeworks via the π…π interactions between pyridine groups decorated on the inorganicchains. Compound4contains two {SbW₈O₃₁} tetravacant polyoxoanion units, two {SbW₉O₃₃}trivacant polyoxoanion fragments. These vacant POM units are connected by two {Sb₃O₄}linking units, two {WO₂} units and four Ln-containing complex units, forming an isolatinghuge POM aggragate. To our knowledge, compounds3and4represent the firstLn-substituting polyoxotungstenbismates decorated by organic ligands.