Kristallstruktur von Kaliumtriflat‐Butyrolacton, [K3(O3SCF3)3(O2C4H6)2]

Crystal Structure of Potassium Triflate‐butyrolactone, [K₃(O₃SCF₃)₃(O₂C₄H₆)₂] Single Crystals of [K₃(O₃SCF₃)₃(O₂C₄H₆)₂] ( 1 ) have been obtained as a by‐product from the reaction of KNPPh₃ with Yb(O₃SCF₃)₃ in THF with subsequent addition of butyrolactone. The structure of 1 consists of three symmetry‐independent potassium ions which are linked by the oxygen atoms of the triflate ions and the butyrolactone molecules to give a supramolecular structure with layers normal to the crystallographic b‐axis. The carbonyl oxygen atoms of both butyrolactone molecules show a μ₃‐bridging function between three K⁺ ions, one of them is, in addition, coordinated by the ring O‐atom in a chelate manner. 1 : Space group P2₁/c, Z = 4, lattice dimensions at 193 K: a = 1155.0(1), b = 1537.2(1), c = 1531.1(1) pm, β = 100.623(7)°, R = 0.0484.     

End‐group modified poly(methyl vinyl ether): Characterization and LCST demixing behavior in water

A range of hydrophilic poly(methyl vinyl ether) (PMVE) polymers was synthesized by living cationic polymerization of methyl vinyl ether (MVE), having different hydrophilic or hydrophobic chain‐end functionalities. The dissimilar end‐groups were either introduced by end‐capping of the growing polymer chain with LiBH₄, methanol, and water or by functional initiation with 2‐bromo‐(3,3‐diethoxy‐propyl)‐2‐methylpropanoate. The synthesized PMVEs were characterized by ¹H NMR, size exclusion chromatography, and matrix‐assisted laser desorption ionization time of flight, displaying a narrow polydispersity. Modulated temperature DSC was applied to study the influence of the nature of the end‐groups on the solubility behavior of PMVE in water. Terminal‐modification with a hydroxyl function improves the solubility, whereas a Br‐containing end‐group causes the polymer to be insoluble in water at room temperature; however, the special type III lower critical solution temperature demixing behavior being maintained. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 461–469, 2006