The first 1,3,2-diazaalumina-[3]ferrocenophanes

The dilithiated derivative 2 of 1,1′-bis(trimethylsilylamino)ferrocene (1) reacts with various aluminum dichlorides RAlCl2 [R = tBu (3a), CH(SiMe3)2 (3b), Si(SiMe3)2 (3d)] in the presence of pyridine to give the respective 1,3,2-diazaalumina-[3]ferrocenophanes 4a,b,d as pyridine adducts, of which 4a could be isolated in good yield and high purity. The aluminum halide (Me3Si)3CAlCl2 in THF did not react with 2. The molecular structure of 4a, determined by X-ray analysis, shows the tert-butyl group in trans-position relative to the N–Si bond vectors. NMR spectra prove that prominent structural features are retained in solution, including restricted rotation about the Al–N(py) bond, shown by low-temperature NMR spectra.