Received 24 November 2012
The title compound, [Al2K2(C2H6N)8(C4H8O)]n, formed during the sonochemical reaction between Al(NMe2)3 and sodium-potassium alloy in the presence of tetrahydrofuran (THF). Its asymmetric unit has two inequivalent K+ sites. One site is coordinated by a THF ligand, and crystallizes as a one-dimensional polymer with a backbone of catenated AlN2K rings. A twofold rotation axis bisects one K+ site and the THF ligand; the second K+ site is situated on an inversion centre, resulting in a planar four-coordination by N atoms. The latter symmetry operation generates the second half of the THF molecule and fills out the coordination sphere of the potassium sites. The chains extend along the c-axis direction and zigzag at the THF-coordinated K+ sites by an angle of 106.02 (5)°.
Several (RR'N)4AlM (M = Li, Na) compounds that have catenated AlN2M chains have been reported previously (Eisler & Chivers, 2006); Rings et al. 2000). The structure of tris(dimethylamino)aluminium is a molecular dimer, see: Ouzounis et al. (1983). Heavily solvated tetraaminoalanates tend to have separated cations instead of catenated chain structures, see: Hensen et al. (1999). For details of the synthesis, see: Ruff (1960); Ouzounis et al. (1983).
Data collection: APEX2 (Bruker, 2008); cell refinement: SAINT (Bruker, 2008); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Sheldrick, 2008); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL.
Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: NK2195 ).
We thank The Office of Naval Research for financial support.
Bruker (2008). APEX2, SADABS and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA.
Eisler, D. J. & Chivers, T. (2006). Can. J. Chem. 84, 443-452.
Hensen, K., Lemke, A., Stumpf, T., Bolte, M., Fleischer, H., Pulham, C. R., Gould, R. O. & Harris, S. (1999). Inorg. Chem. 38, 4700-4704.
Ouzounis, K., Riffel, H., Hess, H., Kohler, U. & Weidlein, J. (1983). Z. Anorg. Allg. Chem. 504, 67-76.
Rings, S., Ischenko, V. & Jansen, M. (2000). Z. Naturforsch Teil B, 55, 730-734.
Ruff, J. K. (1960). J. Am. Chem. Soc. 83, 2835-2839.
Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.