Multi Acid Crown Ether Supramolecular Complexes Were Synthesized And Nature Study

Because of their potential application in materials, life sciences, sorption clathration, catalysis, electric conductivity, magnetism, and photochemistry, et al, super-molecular complexes and polyoxometalates have received considerable attention recently. Moreover, super-molecules have presented special molecular recognition properties when acting as host molecules to interact with guest molecules. Polyoxometalates exhibit different polymerization and structures as the change of chemical circumstance. The combination of super-molecular complexes and polyoxometalates is currently opening up a new direction.We have synthesized a series of polyoxometalates super-molecules by crown ethers, such as DB18C6, DB24C8, B15C5, and polyoxometalates with differert polymerization. Our works have also revealed that crown ethers with different radius choose different polyoxometalates with different polymerization and Mo/W composition.1. Preparation of [Na(DB18C6) (CH₃CN)]₂W₆O₁₉. The crystal was obtained as follow: 0.8g of Na₂WO₄·2H₂O was dissolved in 30 ml CH₃OH, adjusting its PH to 3.0 with hydrochloric acid, 0.1g DB18C6 was added, stirring about 20 hours, the solution was filtered, the residue was dried at room temperature, then transferred into a Teflon-Steel autoclave inside programmable electric furnace reactor with 20 ml CH₃CN as solvent. Solvothermal reaction lasted for 20 hours at 423.15K, and then cooled to room temperature naturally. The complex was characterized by Elemental Analysis, IR, ¹HNMR, X-Ray. The crystal was crystallizes in monoclinic space group, P2₁/n. The complex consists of four basic uints, which are Na⁺, CH₃CN, DB18C6 and W₆O₁₉^2-. Sodium ion was located in the cavity of dibenzo-18-crown-6 with 6 Na-O bonds and coordinated with one of the terminal O atom of W₆O₁₉^2- and the N atom of CH₃CN from two sides of the distorted DB18C6 plane respectively. The anion of WO₁₉^2- was in the middle of two [Na(DB18C6) (CH₃CN)]⁺, to form a sandwich super-molecular complex.2. Preparation of [Na(DB24C8)]₃[AsMo₁₂O₄₀]·9H₂O. The crystal was obtained as follow:0.6g of Na₂MoO₄·2H₂O and 0.2g Na₃AsO₄ were dissolved in 30 ml CH₃OH, adjusting its PH to 4.5 with hydrochloric acid, 0.2g DB24C8 was added, stirring about 20 hours, the solution was filtered, the residue was dried at room temperature, then transferred into a Teflon-Steel autoclave inside programmable electric furnace reactor with 20 ml CH₃CN as solvent. Solvothermal reaction lasted for 20 hours at 423.15K, and then cooled to room temperature naturally. The complex was characterized by Elemental Analysis, IR, ¹HNMR, X-Ray. The crystal was crystallizes in monoclinic space group, P2₁/n. The complex consists of three basic uints, which are Na⁺, DB18C6 and [AsMo₁₂O₄₀]^3-. The crown ethers just coordinate with Na⁺ and have no direct interaction with the polyoxometalate, because the crown ethers have a contorted configuration.3. Preparation of [Na(B15C5)₂][Mo₆O₁₉]. Title complex was synthesized by the following method::0.2g Mo(acac)₂ was dissolved in 30 ml CH₃OH, adjusting its PH to 3.0 with hydrochloric acid, 0.2g B15C5 was added, stirring about 20 hours, the solution was filtered, the residue was dried at room temperature, then transferred into a Teflon-Steel autoclave inside programmable electric furnace reactor with 20 ml CH₃CN as solvent. Solvo-thermal reaction lasted for 20 hours at 423.15K, then cooled to room temperature naturally. Yellow prism suitable for single crystal X-ray diffraction experiment was obtained. It crystallized and characterized in the triclinic system space group Monoclinic, C2/m. The complex consists of three basic uints: Na⁺, B15C5 and Mo₆O₁₉^2-. The crown ethers just coordinate with Na⁺ and have no direct interaction with the polyoxometalate.4. Preparation of [NaL(CH3CN)][NaL][α-PMo₁₂O₄₀][NaL2](L=B15C5). The crystal was obtained as follow: 0.6g of Na₂MoO₄.2H₂O and 0.2g Na₃PO₄ were dissolved in 30 ml CH₃OH, adjusting its PH to 4 with hydrochloric acid, 0.2g B15C5 was added, stirring about 20 hours, the solution was filtered, the residue was dried at room temperature, then transferred into a Teflon-Steel autoclave inside programmable electric furnace reactor with 20 ml CH₃CN as solvent. Solvothermal reaction lasted for 20 hours at 423.15K, and then cooled to room temperature naturally. The complex was characterized by IR, X-Ray. The crystal was crystallizes in triclinic space group, P-1. Thesuper molecular complex contains an [α-PMo₁₂O₄₀]^3- anion and three sodium complexes. In complex of Na(1), sodium cation is encapsulated in the cavity of B15C5 by 5 Na-O bonds and associated with the bridge O atom of [α-PMo₁₂O₄₀]^3-. In complex of Na(2), the sodium cation is not encapsulated in the cavity of B15C5 but sandwiched by two B15C5 and coordinated by eight O atoms of the two B15C5. The sodium coordination geometry is filled by eight crown ethereal oxygens forming the eight coordination mode, so Na(2) has no direct interaction with the [(α-PMo₁₂O₁₀]^3- anion. It is interesting to find that Na(3) has a novel 7 coordination symmetry. Na(3) is coordinated by five crown ethereal oxygens and one terminal oxygen of the [α-PMo₁₂O₁₀]^3- anion and one N atom of CH₃CN.5. Preparation of [Li(B15C5)(CH₃OH)][Mo₆O₁₉]. Title complex was synthesized by the following method:0.2g Mo(acac)₂ was dissolved in 30 ml CH₃OH, then 0.3g LiCl was added, adjusting its PH to 3.0 with hydrochloric acid, 0.2g B15C5 was added, stirring about 20 hours, the solution was filtered, the residue was dried at room temperature, then transferred into a Teflon-Steel autoclave inside programmable electric furnace reactor with 20 ml CH₃CN as solvent. Solvo-thermal reaction lasted for 20 hours at 423.15K, then cooled to room temperature naturally. Brown prism suitable for single crystal X-ray diffraction experiment was obtained. The complex was characterized by IR, X-Ray. The crystal was crystallizes in triclinic space group, P-1. The complex consists of three basic uints: Li⁺, B15C5 and Mo₆O₁₉^2-. The crown ethers just coordinate with Na⁺ and have no direct interaction with the polyoxometalate.