catena-Poly[[(tetra­hydro­furan-κO)potas­sium]-di-μ-dimethyl­amido-κ4N:N-aluminium-di-μ-dimethyl­amido-κ4N:N-potassium-di-μ-dimethyl­amido-κ4N:N-aluminium-di-μ-dimethyl­amido-κ4N:N]

Purdy, A.; Parrish, D.

doi:10.1107/S1600536813003553

Volume 69
Part 3
Page m147
March 2013

Received 24 November 2012
Accepted 4 February 2013
Online 13 February 2013

Key indicators
Single-crystal X-ray study
T = 173 K
Mean (C-C) = 0.003 Å
R = 0.036
wR = 0.107
Data-to-parameter ratio = 31.8
Details

catena-Poly[[(tetrahydrofuran-O)potassium]-di--dimethylamido-⁴N:N-aluminium-di--dimethylamido-⁴N:N-potassium-di--dimethylamido-⁴N:N-aluminium-di--dimethylamido-⁴N:N]

Andrew Purdy ^a ^*⁺ and Damon Parrish ^a ⁺⁺

^aNaval Research Laboratory, 4555 Overlook Av, SW, Washington, DC 20375, USA
Correspondence e-mail: andrew.purdy@nrl.navy.mil

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)°.

Related literature

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).

Experimental

Crystal data

[Al₂K₂(C₂H₆N)₈(C₄H₈O)]
M_r = 278.44
Monoclinic, C 2/c
a = 13.247 (4) Å
b = 12.075 (4) Å
c = 20.822 (7) Å
= 90.979 (5)°
V = 3330.1 (19) Å³
Z = 8
Mo K radiation
= 0.36 mm^-1
T = 173 K
0.74 × 0.57 × 0.42 mm

Data collection

Bruker SMART APEXII CCD diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2008) T_min = 0.776, T_max = 0.863
18795 measured reflections
4928 independent reflections
3986 reflections with I > 2(I)
R_int = 0.023

Refinement

R[F² > 2(F²)] = 0.036
wR(F²) = 0.107
S = 1.03
4928 reflections
155 parameters
H-atom parameters constrained
_max = 0.25 e Å^-3
_min = -0.30 e Å^-3

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 ).

Acknowledgements

We thank The Office of Naval Research for financial support.

References

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.

metal-organic compounds

catena-Poly[[(tetrahydrofuran-O)potassium]-di--dimethylamido-4N:N-aluminium-di--dimethylamido-4N:N-potassium-di--dimethylamido-4N:N-aluminium-di--dimethylamido-4N:N]