Deuterated ionic liquid

In general, isotopic exchange is both expensive and difficult. In the case of many room-temperature ionic liquids, however, the manufacture of deuterated ionic liquids is relatively easily achievable. For example, the general synthesis of l-allcyl-3-methylimidazolium salts is shown in Scheme 4.1-1 [2]. This methodology allows maximum flexibility in the deuteration on the imidazolium cation that is, it can be either ring or side chain deuteration or both. 

SANS measurements. SANS measurements were employed to determine the structural features of microemulsions and the respective arrangement of IL and TX-100, by using three different contrasts. The first set of SANS data, named "full contrast", was obtained with microemulsions in deuterated toluene and allowed the determination of the global form of objects. Data obtained with deuterated ionic liquid in hydrogenated toluene and Triton XlOO show the objects formed by IL it is "core contrast" since IL is assumed to be in the core of the micelles. Third, data obtained in toluene mixture, which matches the deuterated ionic liquid, give the scattering from the TX-100 object it is named "shell contrast". 

Bowron et al. [11] have performed neutron diffraction experiments on 1,3-dimethylimidazolium chloride ([MMIM]C1) in order to model the imidazolium room-temperature ionic liquids. The total structure factors, E(Q), for five 1,3-dimethylimidazolium chloride melts - fully probated, fully deuterated, a 1 1 fully deuterated/fully probated mixture, ring deuterated only, and side chain deuterated only - were measured. Figure 4.1-4 shows the probability distribution of chloride around a central imidazolium cation as determined by modeling of the neutron data. 

The second group of recently developed ionic liquids is often referred to as task specific ionic liquids in the literature [15]. These ionic liquids are designed and optimised for the best performance in high-value-added applications. Functionalised [16], fluorinated [17], deuterated [18] and chiral ionic liquids [19] are expected to play a future role as special solvents for sophisticated synthetic applications, analytical tools (stationary or mobile phases for chromatography, matrixes for MS etc.), sensors and special electrolytes. 

In recent times, the development of new ionic liquids has made great progress. Important developments include a range of new halogen-free ionic liquids (e.g., benzenesulfonates [13], toluenesulfonates, alkylsulfates [14], hydro-gensulfate [15, 16], dicyanamides [17], thiocyanates [18], etc.), as well as functionalized (task-specific) [19-23], fluorinated [24], deuterated [25] and chiral ionic liquids [26-30]. 

Giernoth, R. and Bankmann, D., Transition-metal free ring deuteration of imidazolium ionic liquid cations. Tetrahedron Lett., 47,4293,2006. 

Deuteration of the ionic liquid s cation has not only been applied to obtain proton-free ionic liquids for H-NMR experiments but also as direct probe for the reactivity of 1,3-dialkylimidazolium based ionic liquids vs. Ir(0) nanoclusters [70]. After addition ofD2 to [BMIM][(CF3S02)2N] in the presence of an lr(0) nanocluster Finkeand coworkers found deuterium incorporation at the 2-H, 4-H, 5-H and 8-H positions of the imidazolium cation while the control experiment in the absence of the lr(0) cluster showed no D-incorportion. The authors concluded from their H-NMR experiments that a sequence of N-heterocylic carbene formation by oxidative addition (see Section 3.1.2 for more details) of the imidazolium cation, H/D scrambling atop the nanocluster surface, followed by the reductive elimination of a C-D bond takes place. From carefiil kinetic investigations the authors concluded that the co-ordinatively unsaturated nanocluster surface acts indeed as the true catalyst for the H/D-ejadiange reaction. 

The first demonstration of the formation of a non-polar alkyl chain layer between a room-temperature ionic liquid and alcohol interface was reported by Iwahashi et al. [46]. In their study, the room-temperature ionic liquid [C4mim][PF6] in contact with deuterated linear... 

Abe, H., Imai, Y., Takekiyo, T. Yoshimura, Y. (2010a) Deuterated Water Effect in a Room Temperature Ionic Liquid N,N-DiethyI-N-methyl-N-2-methoxyethyl Ammonium Tetrafluoroborate, /, Phys. Chem. B Vol. 114 2834 2839. 

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