An Investigation of the Symmetric and Asymmetric Cleavage Products in the System Aluminum Trihalide/1‐Butylimidazole

Abstract

Mixtures of AlX (X=Cl, Br) with 1-butylimidazole (BuIm) in various ratios were investigated. The mixtures were characterized by multinuclear ( H, Al, C, and N) NMR, IR, and Raman spectroscopy and in part by single-crystal X-ray diffraction. Depending on the molar fraction x(AlBr ) of the AlBr -based mixtures, the cationic aluminum complexes [Al(BuIm) ] and [AlBr (BuIm) ] , the neutral adduct [AlBr (BuIm)], as well as the anions Br , [AlBr ] , and [Al Br ] could be identified as the products of the symmetric and asymmetric cleavage of dimeric Al Br . Furthermore, there are hints at the formation of [AlBr (BuIm) ] or related cations. Comparison of the AlBr /BuIm system with AlCl -based mixtures revealed the influence of the halide: In contrast to AlBr , the trication [Al(BuIm) ] could not be detected as main product in a 1:6 mixture of AlCl and BuIm. Additionally, [AlCl (BuIm)] crystallizes from a mixture with x(AlCl )=0.60 at room temperature, whereas the corresponding AlBr -based mixture remains liquid even at +6 °C. Three AlBr -based mixtures are liquid at room temperature, whereas all other mixtures are solids with melting points between 46 and 184 °C. The three liquid mixtures exhibit medium to high viscosities (117 to >1440 mPa s), low conductivities (0.03-0.20 mS cm ), but high densities (1.80-2.21 g cm ). Aluminum could be successfully deposited from one of the neat Lewis acidic mixtures of the AlBr -based system.

Rechargeable aluminum batteries: effects of cations in ionic liquid electrolytes

“…The peaks at 311 cm À1 and 433 cm À1 increased in intensities and the peak at 350 cm À1 decreased in intensity as more AlCl 3 was added, indicating that more Al 2 Cl 7 À and fewer AlCl 4 À were formed at higher AlCl 3 /EMIC or AlCl 3 /Py13Cl ratios. The chemical equations govern these reactions were as follows: [23][24][25] AlCl 3 + EMIC / EMI + + AlCl 4 À (AlCl 3 ratio # 1) (1a)…”

How a Transition‐Metal(II) Chloride Interacts with a Eutectic AlCl3‐Based Ionic Liquid: Insights into the Speciation of the Electrolyte and Electrodeposition of Magnetic Materials

“…It has been observed that both [AlCl 4 ] À and [Al 2 Cl 7 ] À could be present in the Lewis acidic mixtures. [33] Ac hange in the intensities of the peaks at 299 and 415 cm À1 was observed upon adding FeCl 2 to L/AlCl 3 (1:1.2:0.05 mol ratio). Quite ab road peak was observed at 344 cm À1 for L/AlCl 3 /FeCl 2 (1:1.2:0.15 mol ratio).…”

“…[33] The authorsf ound differences in the 27 Al chemical shifts upon varying the mole fraction of AlCl 3 and 1-butylimidazole, which can be due to the formationo fd ifferent Al complexes. [33] Ad ifference in Al complexation was also noticed for mixtures of AlCl 3 with amides. [21] Thus, the asymmetricc leavage of metal halides and the nature of the coordination show ad ependence on both the donor ligandsa nd on metal halides.…”

“…[29] For metal-ion speciation in ILs (or DESs), we refer to ac ritical review by Estager et al and to other relevant articles that are available in the literature. [30][31][32][33][34] The influence of ligands on the asymmetric cleavage and on the nature of the coordination and the number of coordination sites is still required forad etailed understandingo fL CCs. For instance, complexes formed from AlCl 3 and neutral ligands ( 4-propylpyridine or N-butylpyrrolidine) are different upon varying the concentration of AlCl 3 in the mixtures.…”

“…For metal‐ion speciation in ILs (or DESs), we refer to a critical review by Estager et al. and to other relevant articles that are available in the literature …”