Syntheses And Properties Study Of Keggin POM Compounds Based On Pyridinyl Five Membered Heterocycle Derivatives

In this work,we used hydrothermal technique to obtain fourteen saturated and mono-substituted Keggin based compounds by using pyridinyl five membered heterocycle derivatives and continuously adjusting the reaction temperature and pH.In the aspect of characterization,we mainly used X–ray single crystal diffractometry,IR spectrum,TG and XRD.In terms of properties,we mainly tested the electrochemical properties,magnetism and photocatalytic properties of all compounds.1.We have obtained four compounds based on Keggin anions by using three pyridinyl five membered heterocycle derivatives,namely a 1D chain of 1,discrete dimer of 2,mono–capped anion of 3,and a 3D framework of 4.All of them show good photocatalytic activity for degradation of MB.Moreover,compounds 1-4 have good electrocatalytic activity and can be used as amperometric sensors for nitrite.In addition,compound 4 has a selective response to Hg²⁺ion.[Ag（Py2Piz）₂(H₂PW₁₂O₄₀)]·2H₂O（1）[Ag₄（Py2Piz）₄(H₂SiMo₁₂O₄₀)₂]·2H₂O（2）[Ag₂（Py3Piz）₂（H₂O）₂(H₃SiMo₁₂O₄₀)₂]·8H₂O（3）{Ag₄（Py2TTz）₄[Ag(PMo₁₂O₄₀)₂]}·Ag（Py2TTz）·2（Py2TTz）·6H₂O（4）Py2Piz=4,5–Bis（2–pyridinyl）imidazolePy3Piz=2–（4–pyridyl）4,5–di（2–pyridinyl）imidazolePy2TTz=2,5–Bis（4–pyridyl）thiazolo[5,4–d]thiazole2.Three lanthanide atom mono-substituted POM dimers were synthesized by using vacant Keggin POM.Three compounds all have 1D chain structures.The 1D chains were formed directly connected by anionic dimers,while Py2TTz ligands are dissociate around POMs.In addition,the stability and electrochemistry properties of these compounds were also studied.[Eu（H₂O）₂HPW₁₁O₃₉][H₃（Py2TTz）_2.5]·6H₂O（5）[La（H₂O）₃HPW₁₁O₃₉][H₃（Py2TTz）₂]·10H₂O（6）[Pr（H₂O）₃HPW₁₁O₃₉][H₃（Py2TTz）₂]·13H₂O（7）Py2TTz=2 2,5–Bis（4–pyridyl）thiazolo[5,4–d]thiazole3.Seven lanthanide atom mono-substituted POM dimers were synthesized by using vacant Keggin POM and DiTOm.All compounds have 1D chain structures.Compounds 8–14 own 1D chains induced by coordination of dithioacetamide,while Py2TTz ligands are dissociate around POMs.In addition,the stability,electrochemistry and magnetism of these compounds were also studied.[Sm（DiTOm）（H₂O）HPW₁₁O₃₉][H₃（Py2TTz）_2.5]·16H₂O（8）[Tb（DiTOm）（H₂O）HPW₁₁O₃₉][H₃（Py2TTz）_2.5]·14H₂O（9）[Gd（DiTOm）（H₂O）HPW₁₁O₃₉][H₃（Py2TTz）_2.5]·14H₂O（10）[Dy（DiTOm）（H₂O）HPW₁₁O₃₉][H₃（Py2TTz）_2.5]·13H₂O（11）[Ho（DiTOm）（H₂O）HPW₁₁O₃₉][H₃（Py2TTz）_2.5]·14H₂O（12）[Y（DiTOm）（H₂O）HPW₁₁O₃₉][H₃（Py2TTz）_2.5]·14H₂O（13）[Yb（DiTOm）（H₂O）HPW₁₁O₃₉][H₃（Py2TTz）_1.5（PyTTz）]·18H₂O（14）DiTOm=Dithio oxamidePy2TTz=2,5–Bis（4–pyridyl）thiazolo[5,4–d]thiazole...