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]

Abstract

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)°.