Potassium chlorido-tris-(hypersil-oxy)aluminate dimer.

The tris-(tri-methyl-silylsiloxide) ligand, also known as hypersiloxide, is an extremely bulky group. In an attempt to make the monomeric Al(OSi(SiMe3)3)3, AlCl3 was combined with 3 equiv. of potassium hypersiloxide. The crystalline product isolated (40% yield), namely di-μ3-chlorido-bis-[μ2-tris-(tri-methyl-sil-yl)silanolato]tetra-kis-[tris-(tri-methyl-sil-yl)silanolato]dialuminium-dipotassium, [Al2K2Cl2(C19H27OSi4)6], is a KCl adduct of aluminium tris(hypersilyloxide) that is dimerized through a planar K2Cl2 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 supra-molecular coordination.