Ionic Liquids with More than One Metal: Optical and Electrochemical Properties versus d‐Block Metal Combinations

Abstract

Thirteen N-butylpyridinium salts, including three monometallic [C 4 Py] 2 [MCl 4 ], nine bimetallic [C 4 Py] 2 [M 1Àx a M x b Cl 4 ]a nd one trimetallicc ompound [C 4 Py] 2 [M 1Ày-z a M y b M z c Cl 4 ](M = Co, Cu, Mn; x = 0.25, 0.50 or 0.75 and y = z = 0.33), were synthesized and their structure and thermala nd electrochemical properties were studied. All compoundsa re ionic liquids(ILs) with melting points between 69 and 93 8C. X-ray diffraction provest hat all ILs are isostructural. The conductivity at room temperature is be-tween1 0 À4 and1 0 À8 Scm À1 .S ome Cu-based ILs reach conductivities of 10 À2 Scm À1 ,w hichi s, however, probablyd ue to IL dec. This correlates with the opticalb andgap measurementsi ndicating the formation of large bandgap semiconductors.A te levated temperaturesa pproaching the melting points, the conductivities reach up to 1.47 10 À1 Scm À1 at 70 8C. The electrochemical stability windowso ft he ILs are between2.5 and 3.0 V.

Tetrahalidometallate(II) Ionic Liquids with More than One Metal: The Effect of Bromide versus Chloride

“…While the intensity of the reflections differs to some extent, which is probably due a high number of defects and disorder in each sample, the position of the reflections are identical. As with previously published data on chloridecontaining MILs, [42] the background of the patterns is relatively noisy.…”

“…Additionally, it is important to keep in mind that the starting point for the DFT calculations was the previously published copper-chloride-containing MIL, which possesses a different albeit isostructural and isoelectronic anion. 42 This also shows the transferability of the method from better-known compounds to lesser known structures.…”

“…We have recently reported the first data of chloride-based MILs with a series of d-metals and their mixtures and demonstrated a strong influence of the metal cation on the properties of the MILs. [42] In line with previous data, the N-butylpyridinium cation was used as the counterpart of the tetrabromidometallate (II) anion. This allows for comparisons with the chloride analogues published before and ensures a higher stability and higher melting points of the compounds compared to imidazolium-based compounds.…”

Metal Sulfide Nanoparticle Synthesis with Ionic Liquids – State of the Art and Future Perspectives

“…[114,215] While this concept is just being established, we have recently demonstrated that a wide variety of ILPs with different metal/metal ratios and various metal/metal combinations are accessible. [216] Clearly, following the concept recently demonstrated, these and other ILPs are attractive for the formation of (metal sulfide) nanoparticles with a highly flexible and potentially quite unusual composition. [114] Similar observations can also be made for the sulfur sources, not only for metal containing ILs.…”

“…This is particularly interesting when considering the synthesis of compounds with more complex compositions: suitable ILPs can be made to contain all metal ions needed for product formation and thus possibly also provide access to non‐stoichiometric compounds that are not easily accessible otherwise [114,215] . While this concept is just being established, we have recently demonstrated that a wide variety of ILPs with different metal/metal ratios and various metal/metal combinations are accessible [216] . Clearly, following the concept recently demonstrated, these and other ILPs are attractive for the formation of (metal sulfide) nanoparticles with a highly flexible and potentially quite unusual composition [114] …”