Synthesis and Structures of Bis(tetramethylipiperidino)aluminum Halides‐X‐ray Crystal Structures of tmp₂AlX (X = Cl, Br, I) and [tmp₂A1(μ‐F)l₂

N‐Lithio‐2,2,6,6‐tetramethylpiperidine [Li(tmp)] reacts with AlX 3 (X = Cl, Br) in diethyl ether/ n‐hexane solution to generate the products of substitution and ether cleavage, [tmpAl(X)(μ‐OEt)], ( la , X = Cl; 1b , X = Br). However, when the reaction is allowed to proceed in n‐hexane alone, an almost quantitative yield of compounds tmp 2 AlX ( 2a , X = Cl; 2b , X = Br; 2c , X = I) is obtained. According to 27 AI‐NMR spectroscopy, mass spectroscopy, cryoscopy, and X‐ray crystal structure determinations, these compounds are monomeric in the solid state, in solution, and in the gas phase. 2b reacts with AgBF 4 yielding the fluoride‐bridged dimer (tmp 2 AlF), 2d , as shown by X‐ray crystal structure determination.