Dipl.-Chem. Michael Hog
Room: 340 (Chemie I) Telephone: +49 (0) 761 203-6116 e-mail: michael.hog@ac.uni-freiburg.de
Keywords: Ionic liquids, redox-flow batteries, haloaluminates |
The cleavage of the halide-bridged dimeric compounds Al2X6 (X = Cl, Br, I) with O-, N-, or P-ligands (L) can lead to two different types of products. Neutral Compounds such as (Py)AlCl3[1] are formed, if the Lewis-base cleaves the aluminum halide symmetrically in two identical species. The asymmetric cleavage results in an ionic product. Aluminum is the central atom in the cation and has a coordination number of four (e.g. [(en)AlCl2][AlCl4][2]) or six (e.g. [(Py)4AlCl2][AlCl4][3]). The melting point of the products can be decreased by the use of asymmetric ligands. Liquid cleavage compounds are called liquid coordination complexes (LCCs)[4].
Figure 1: Asymmetric and symmetric cleavage of Al2X6 (X = Cl, Br, I).
I synthesize mixtures of different Lewis-bases with aluminum halides. The main interest is the dependence of the products on the mole fraction of the metal halide. Another part of this project is the deposition of aluminum from the pure mixtures or the dissolved complexes. The reduction of the metal can occur from the cationic species. This should change significantly the deposition character of these mixtures compared to the deposition of aluminum from haloaluminate ionic liquids, in which the dominating metal containing species is the anion [Al2X7]− (X = Cl, Br).
References:
[1] A. Dimitrov, D. Heidemann, E. Kemnitz, Inorg. Chem. 2006, 45, 10807–10814.
[2] C. Trinh, M. Bodensteiner, A. V. Virovets, E. V. Peresypkina, M. Scheer, S. M. Matveev, A. Y. Timoshkin,
Polyhedron 2010, 29, 414–424.
Polyhedron 2010, 29, 414–424.
[3] P. Pullmann, K. Hensen, J. W. Bats, Z. Naturforsch. 1982, 37B, 1312–15.
[4] F. Coleman, G. Srinivasan, M. Swadźba-Kwaśny, Angew. Chem. Int. Ed. 2013, 52, 12582–12586.