Counteranion metathesis

Metathesis of anion with ammonium and lithium salts we try to perform a counteranion metathesis of the IL with NH4BF4 salt in order to try to improve the reaction yield. The solvent used during the reaction is acetone which allows the solubilisation of final product but not the one NHiBr, by-product of the reaction, which makes the purification easier. Moreover the solvent is simple to remove. The reaction is carried out with one molar equivalence of IL ammonium salt which are soluble in acetone. The byproduct is removed by filtration and the filtrate is concentrated under vacuum to get a liquid or a solid. Yields are quite improved compare to the first metathesis (table 1, entry 2,6,10,14). 

The combination of a linear bifunctional telechelic precursor with a tricarboxylate counteranion produced a self-assembly that consisted of three polymer units and two counteranions under dilution. Subsequent heat treatment produced a pair of covalently fixed constitutional isomers, namely manacle-shaped and 0-shaped polymers (Scheme 18.3b) [6, 15]. These relevant pairs of polymeric isomers were formed from a self-assembly of two units of a three-armed star telechelic precursor and three units of a dicarboxylate counteranion [16], as well as from the double-metathesis condensation of an H-shaped telechehc polymer precursor having four alkene end groups (Scheme 18.3c) [17]. 

An electrostatic self-assembly of two units of a linear telechelic precursor and a unit of a tetracarboxylate counteranion and subsequent covalent conversion produced a spiro-dicydic 8-shaped polymer effectively (Scheme 18.5a) [6, 9-11]. Alternatively, a four-armed star telechelic precursor having alkene end groups was subjected to a intramolecular metathesis condensation to form an 8-shaped... 

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