Potassium chloridotris(hypersiloxy)aluminate dimer

The tris(trimethylsilylsiloxide) ligand, also known as hypersiloxide, is an extremely bulky group. In an attempt to make the monomeric Al(OSi(SiMe 3 ) 3 ) 3 , AlCl 3 was combined with 3 equiv. of potassium hypersiloxide. The crystalline product isolated (40% yield), namely di-μ 3 -chlorido-bis[μ 2 -tris(trimethylsilyl)silanolato]tetrakis[tris(trimethylsilyl)silanolato]dialuminiumdipotassium, [Al 2 K 2 Cl 2 (C 19 H 27 OSi 4 ) 6 ], is a KCl adduct of aluminium tris(hypersilyloxide) that is dimerized through a planar K 2 Cl 2 ring, with K—Cl distances of 3.1131 (8) and 3.319 (3) Å, and ring angles of 77.41 (2) and 102.60 (2)°. This ring is on an inversion center, and there is no supramolecular coordination.