Synthese,Characterizations And Catalytic Properties Of Arm-type Dawson Sandwich-type Tungstophosphates Estertin Derivatives

The transition metal ions were replaced by organometallic groups when the sandwich-type compound Na₈H₈[????-{M₄?H₂O?₂(P₂W₁₅O₅₆)₂}]·nH₂O(M=Mn,n=61;M=Co,n=55,abbreviated as Mn-P₂W₁₅5 and Co-P₂W₁₅,respectively)based on trilacunary Dawson tungstophosphate Na₁₂P₂W₁₅O₅₆·18H₂O(abbreviated as P₂W₁₅)met with estertin Cl₃SnCH₂CH₂COOCH₃ in NaCl solutions,thus forming two novel Dawson sandwich-type tungstophosphate,i.e.{C?NH₂?₃}₁₂H₄[????-{?Sn?C₃H₄O₂??₂Mn₂(P₂W₁₅O₅₆)₂}]·22H₂O and{C?NH2?3}12H4[????-{?Sn?C3H4O2??2Co2?P2W15O56?2}]·9H2O(abbreviated as SnR-Mn-P₂W₁₅5 and SnR-Co-P₂W₁₅,respectively)decorated by two open chain carboxyethyltin groups and two transition metals.This represents that the carboxyethyltin group for the first time grafted to Dawson sandwich-type POM.X-ray single-crystal diffraction,elemental analysis,IR spectroscopy and NMR,etc.analyses indicate that the organic and inorganic metals are located in the symmetric position of the center,the orginal precursor named estertin hydrolyze into carboxyethyltin during the reaction course,and take the place of transition metals once seated in the so-called equatorial region as well.Interestingly,an open chain structure instead of cyclic carboxyethyltin is obtained,which is the distinguishing feature of title compounds.The attachment of the chain carboxyethyltin groups to both sides of the center zone of the POMs,which led to the formation of double arm-type POMs,providing a probability for further functionalization.It can be said that the present work make a breakthough in the synthetic field of single crystalline POM estertin derivatives,and will lay a solid foundation for follow-up work.1.The electrocatalytic activities of SnR-Mn-P₂W₁₅5 and SnR-Co-P₂W₁₅5 towards the reduction of hydrogen peroxide and nitrite were performed.The results show that the electrocatalytic activity of SnR-Mn-P₂W₁₅5 is significantly higher than those of the parent compounds.2.Selected the synthesis of cyclohexanone ethylene ketal as a model reaction to estimate the acid-catalytic activities of SnR-Mn-P₂W₁₅,SnR-Co-P₂W₁₅5 and the parent compounds.The results informed that SnR-Mn-P₂W₁₅5 can be used as an excellent eco-friendly catalyst for the reaction of carbonyl protection.3.Selected the oxidation of cyclohexanol to cyclohexanoneas as a model reaction,to evaluate the oxidative catalysis activities of SnR-Mn-P₂W₁₅5 and SnR-Co-P₂W₁₅preliminarily.SnR-Mn-P₂W₁₅5 exhibits better catalytic effect in the available qualification than those of the parent materials.4.A preliminary evaluation of degradation and adsorption of SnR-Mn-P₂W₁₅ and the parent compound Mn-P₂W₁₅5 towards dye were performed using the photocatalytic degradation of RhB as a model reaction.The research results show that Mn-P₂W₁₅ exhibits certain catalytic effect under the given conditions,while SnR-Mn-P₂W₁₅ displays intense adsorption effect.