Deuterated Water Effect in a Room Temperature Ionic Liquid: N,N-Diethyl-N-methyl-N-2-methoxyethyl Ammonium Tetrafluoroborate

A deuterated water effect in the room temperature ionic liquid (RTIL) N,N-diethyl-N-methyl-N-2-methoxyethyl ammonium tetrafluoroborate, [DEME][BF4], is observed in its crystal domain structures; crystallization temperature, T-c; crystal superstructures; and volume contractions. The above effect, seen in [DEME][BF4]-0.9 mol % H2O mixtures, is reduced in 1.0 mol % 0.75H(2)O center dot 0.25D(2)O and 0.9 mol % 0.5H(2)O center dot 0.5D(2)O mixtures and is completely Suppressed in 1.3 mol % D2O mixtures. Interestingly, T-c decreased systemically with D Substitutions of water. In contrast to the crystal state, it was found that there is no difference between H2O and D2O mixtures in the liquid state, on the basis of X-ray diffraction patterns. At around 80-90 mol % H2O, the intermolecular correlation of [DEME][BF4] as a local structure changes to that of bulk water.