No abstract

a b s t r a c tThe bis(trifluoromethanesulfonyl)amide anion ([Tf 2 N] À ) has frequently been used as a component of ionic liquids. To investigate the effect of this anion and alkyl substituents on the thermal properties of macrocyclic metal complexes, cobalt(III) cyclam complexes [Co(cyclam)Cl 2 ][Tf 2 N] and its monoalkyl derivatives were prepared (cyclam = 1,4,8,11-tetraazacyclotetradecane). The corresponding hexafluorophosphate salts were also prepared and characterized. The salts with propyl and hexyl substituents melted at 171°C and 153°C, respectively, whereas other salts decomposed above 220°C without melting. X-ray crystallography revealed the formation of intermolecular hydrogen bonds involving the NH hydrogens, which are responsible for the high melting points.

In recent years, solvate and protic ionic liquids (ILs) have attracted much attention. We synthesized both types of ILs from alkyl aza-crown ethers (L = N-propyl-1-aza-15-crown-5 (L) and N-CFCH-1-aza-15-crown-5 (L)). The solvate ILs [ML][TfN] (M = Na, K) were solids (T = 58-68 °C), whereas the solvate ILs [ML][TfN] (M = Li, Ag) and protic ILs [HL][TfN] were liquids with low glass transition temperatures. The ILs containing Na ions were more crystalline and exhibited higher melting points than the other ILs. The decomposition temperatures of the protic ILs were higher than those of the solvate ILs. A protic IL with a paramagnetic anion, [HL][FeCl] (T = 70.5 °C), was also synthesized and its crystal structure was determined. The solvate ILs [NaL][X] (X = Cl, CFCO, TsO, PhSO) exhibited a lower critical solution temperature (LCST)-type behavior in water. The effects of salt addition on the LCST of L were also investigated. The LCST of these ILs generally increased with increasing hydrophilicity or basicity of the counter anion. This tendency, which is nearly opposite to that of ILs with quaternary onium cations, is ascribed to the amphiphilic nature of the cation. The corresponding protic ILs did not exhibit LCST behavior.

Organo-silicon compoundsOrgano-silicon compounds S 0060 Indium-and Zinc-Mediated Allylation of Difluoroacetyltrialkylsilanes in Aqueous Media. -The title reaction provides a useful method to prepare fluorinated homoallyl alcohols which are of biological and synthetic interest. Formation of silyl enol ethers via Brook rearrangement is not observed. -(CHUNG, W. J.; HIGASHIYA, S.; OBA, Y.; WELCH*, J. T.; Tetrahedron 59 (2003) 50, 10031-10036; Dep. Chem., State Univ. N. Y., Albany, NY 12222, USA; Eng.) -Jannicke 13-131