Study On Synthesis Of Functional Supramolecular Complexes And Application On Catalytic Polymerization Of Styrene In Emulsion

Constructing organic inorganic supramolecular complexes with the higly ordered structure by the reaction of multi dentate ligands with transition metal ions via coordinative bonds, hydrogen bonds andÏ€-Ï€interactions has become the hot research field in coordination chemistry, supramolecular chemistry and material chemistry. Design and syntheses of novel multi functional ligands, and research on their supramolecular complexes through the self assembly approach have been the very attractive and important aspect due to their intriguing structural diversity and potential application on catalysis for chemical transformation, molecular conductivity, magnetism, luminescence, photochromism and electrochromism, etc.The innovative points of this work are as follow:(1)By using hydrothermal method, four new supramolecular compounds from five ligands: 1,10 phen,α,α'-bipy, 2,6 H₂PDA, and heteropolymetallate of Dawson structure with P, N, O as coordinating atoms, and transition metal ions: Cu(II) and Cd(II), were designed, synthesized and characterized. They are: [Cu(2,2'-bipy)₃]3(P₂W₁₈O₆₂) 2H₂O, [Cu(phen)₃][{Cu(phen)2}{Cu(phen)2}(P₂W₁₈O₆₂)]·2H₂O, [Cd3(PDA)₃(2,2'-bipy)₃·2H₂O] CH₃OH 6.5H₂O, [4,4'-bipyH₂][4,4'-bipyH]2.5(P₂W₁₈O₆₂) [4,4'-bipyH1.5] 2H₂O.Their single crystals were obtained and resolved, their electrochemical and optical properties were explored. A new theory and practice is provided for the synthesis of the molecule based material with topology.(2) Two supramolecular complexes UO2Cl4 (Hphen)2 and H4UO2(CO3)₃ of U(VI) from actinide series, were designed, synthesized and characterized. No literature report has been appeared, as to our knowledge. The compound UO2Cl4(Hphen)2 and its film all have strong fluorescence.(3) A ligand containing P and O and a nickel complex were synthesized using similar method reported in literature, they were used as catalyst in the catalytic polymerization in emulsion, syndiotactic polystyrene was obtained, and the reaction kinetics of the above process was studied.The main results of the current studies are:1. Two mixed ligand complexes of 1,10-phen, 2,2'-bipy with heteropolymetallate of Dawson structure, [Cu(phen)₃][{Cu(phen)2}{Cu(phen)2}(P₂W₁₈O₆₂)]·2H₂O and [Cu(2,2'-bipy)₃]3 (P₂W₁₈O₆₂) 2H₂O, were synthesized and characterized. The single crystal X ray diffraction results show interestingly different packing modes. The anion, [Cu(phen)2Cu(phen)2 (P₂W₁₈O₆₂)]2–, of the [Cu(phen)₃][{Cu(phen)2}{Cu(phen)2}(P₂W₁₈O₆₂)]·2H₂O complex forms a one dimensional chain through hydrogen bonds, these 1D chains form two-dimensional supramolecular structure by alternativeÏ€-Ï€interactions; there exists two different coordination numbers for Cu(II) in the complex, two of the Cu(II) ions form trigonal bipyramidal structure by coordinating with two 1,10-phen and the terminal O from the heteropolymetallate anion, while the other Cu(II) forms octahedral geometry with three 1,10-phen molecules. The major difference of the structure of the other complex, [Cu(2,2'-bipy)₃]3(P₂W₁₈O₆₂) 2H₂O, is that the heteropolymetallate anion does not participate in the coodination, but as counter anion, and there exists Jahn-Teller distortion for all of the three Cu(II) cations. The redox behavior of the two complexes was dominated by the heteropolymetallate anions from the results of cyclic voltammetry, the reduction of W(VI) from [Cu(phen)₃][{Cu(phen)2}{Cu(phen)2}(P₂W₁₈O₆₂)]·2H₂O has three steps, gaining two electrons in each step, while that from [Cu(2,2'-bipy)₃]3(P₂W₁₈O₆₂) 2H₂O has four steps, gaining a total of 7 electrons instead of 6 of the previous compound.2. A trinuclear supramolecular complex with mixed ligand, [Cd3(PDA)₃(2,2'-bipy)₃ 2H₂O] CH₃OH 6.5H₂O, was synthesized using hydrothermal method, the results from single crystal X-ray diffraction demonstrate that there exists three different coordination environments for Cd, all of them have distorted pentagonal bipyramidal geometry with coordination number of 7, where the carboxylate anion is used as bridging ligand. The O atom from carboxylate and H from water forms hydrogen bond, there are also H bond between water molecules, these two types of H bonds form an alternative arrangement of 5- and 6-membered ring, extending to a 2D network structure along a and b axis. The electronic spectroscopy of the complex shownπ→π* transitions, forming a broad band. Under excitation of 325 nm UV light at ambient temperature, relatively strong transition ofÏ€*→n was observed in DMSO solution, which originates from H₂PDA, strong fluorescent emission was observed at 418 nm, which can be attributed to ligand to metal charge transfer. The emission spectra of the Cd complex in solid state is totally different from that in solution state at room temperature, on the excitation at 325 nm, there is only one band appears at 460 nm, a relative large red shift comparing with that in solution, this result demonstrates that there exists strongÏ€-Ï€interactions between neighboring 2,2'-bipy molecules.3. Two supramolecular complexes of uranium, UO2Cl4 (Hphen)2 and H4UO2(CO3)₃, were designed and synthesized. The data from single crystal X-ray diffraction suggest that 1,10-phen was protonated and not coordinating with U in the complex, the two phen molecules without coordination in the cell were parallel at alternative positions. A 2D structure formed through H bond between 1,10-phen and [UO2Cl4]2- anion, the strongÏ€-Ï€interaction between 1,10-phen molecules helps the formation of a 3D supramolecular structure with rhombic channel along c direction. XPS data show that uranium exists as U(VI) in UO2Cl4 (Hphen)2 complex. At room temperature, A strong and broad emission band at 422 nm was observed for the UO2Cl4 (Hphen)2 water solution on the excitation at 351 nm, this can be attributed toÏ€-Ï€* charge transfer transition between phen from the complex and the protonated phen, as well as solvent effects. The emission band red-shifts for the complex in PVA film comparing with that in solution because of the strongÏ€-Ï€interactions between phen molecules in solid state. The single crystal X-ray diffraction results of H4UO2(CO3)₃ complex demonstrate that there are two types of 1D chain formed through H-bond, the intercrossing of them forms 2D network. Three CO32 - anions all coordinate with UO2(II), each anion forms a 4-membered ring through the coordination of two O atoms, and the three 4-membered rings formed are coplanar. The reason of stable 4-membered ring formation is because of the relative large size of U, which reduces strain effectively.4. A novel heteropolymetallate containing water chain, [4,4'-bipyH₂][4,4'-bipyH]2.5 (P₂W₁₈O₆₂)[4,4'-bipyH1.5] 2H₂O, was synthesized, the single crystal X-ray diffraction results suggest partial protonation of different degrees for all of the four 4,4'-bipy molecules, H bond and weak intermolecular forces arrange heteropolymetallate anions as 1D chain, 2D network is also formed through weak intermolecular forces. The water molecules form an ABAB type tetramer (H₂O)4 through H-bond, the serial connection of tetragons formed by these tetramers helps the formation of water chain, which stabilizes the 3D supramolecular structure like glue. Cyclic voltammetry results show four pairs of redox bands in the range of -0.8⁰.3V, indicating good redox properties of the complex.5. Using Ni(COD)2 and ligand containing P and O as catalyst in the catalytic emulsion polymerization, syndiotactic polystyrene was obtained, and the reaction kinetics of the above process was studied. The product was characterized with 13CNMR,1HNMR,IR,GPC,TEM,TG etc. The best polymerization condition for this reaction system was found to be: emulsifier 1.50g。[St]0=1.79mol-L-1,T=60℃,t=2h,[Ni(COD)2]=1.102mmol-L-1, the yield was 78%. The activity of the catalyst is 662.14gPS (gNi h)-1. The emulsion particle size was 100～120nm by the results of particle size analysis and TEM techniques. The GPC analysis results show that: the weight average molecular weight Mw is 1.64×106, while the number-average molecular weight Mn 9.79×105, width of molecular weight distribution 1.6. Very good thermal stabilities are observed in the temperature range of ambient temperature up to～376℃, the 13CNMR,1HNMR and IR analysis results proved the syndiotactic structure. Preliminary study on the kinetics of the polymerization indicates that: the apparent activation energy Ea is 20.76KJ/mol, the rate laws are: Rp=1.687×[St]0.241[Ni(COD)2]0.542(when [St]≤1.79mol-L-1), Rp=0.03683×[St]-0.187[Ni(COD)2]0.542 (when [St]>1.79mol-L-1).No literature report has been appeared for the emulsion polymerization of styrene by the catalyst, as to our knowledge.