Structure determination of zinc iodide complexes formed in aqueous solution

Structures of the complexes formed in aqueous solutions between zinc(II) and iodide ions have been determined from large-angle X-ray scattering, Raman and far-IR measurements. The coordination in the hydrated Zn²⁺ hexaaqua ion and the first iodide complex, [ZnI]⁺, is octahedral, but is changed into tetrahedral in the higher complexes, [ZnI₂(H₂O)₂], [ZnI₃(H₂O)]^– and [ZnI₄]^2–. The Zn-I bond length is 2.635(4)Å in the [ZnI₄]^2– ion and slightly shorter, 2.592(6)Å, in the two lower tetrahedral complexes. In the octahedral [ZnI(H₂O)₅]⁺ complex the Zn-I bond length is 2.90(1)Å. The Zn-O bonding distances in the complexes are approximately the same as that in the hydrated Zn²⁺ ion, 2.10(1)Å.     

Coordination around thorium(IV) in aqueous perchlorate,chloride and nitrate solutions

The coordination around the thorium(IV) ion in aqueous perchlorate, chloride and nitrate solutions has been determined from large angle X-ray scattering measurements. In perchlorate solutions, where inner-sphere complexes are not formed, the first coordination sphere contains 8.0±0.5 water molecules with Th-H₂O bond lengths of 2.48₅ Å. In chloride solutions inner-sphere complexes are formed, which lead to an increase in the coordination number. In nitrate solutions the nitrate ions are bonded as bidentate ligands to the thorium ion. The bond lengths are similar to those found in crystalline hydrates of thorium nitrate. The coordination numbers found for thorium(IV) in solution are compared with previously reported values for lower charged ions of similar size.On leave from Department of Inorganic Chemistry Royal Institute of Technology S-10044 Stockholm Sweden     

Synthesis and characterization of oxazoline-functional polymer particles by free radical nonaqueous dispersion polymerization

A novel oxazoline-functional methacrylate was prepared and employed as comonomer to produce nonaqueous dispersions of oxazoline-functional polymer particles. In nonaqueous free radical dispersion copolymerization of methylmethacrylate in the presence of oxazoline-functional methacrylate, ethyleneglycoldimethacrylate crosslinking agent, AIBN initiator, and polystyrene-block-poly(ethene-alt-propene) dispersing agent, the average polymer particle size, varying between 100 and 500 nm, was controlled by the dispersing agent contents. According to titration with HClO₄ all oxazoline groups regardless of their location at particle surface or bulk, were accessible. Glass transition temperature decreased from 120 to 0°C when oxazoline functional methacrylate was increased from 0 to 95 mol %. As imaged by atomic force microscopy incorporation of the new oxazoline-functional methacrylate improved film formation. Oxazoline-functional polymer particles were easy to redisperse in a variety of other diluents. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35: 2539–2548, 1997