Synthesis of carbaalane halogen derivatives

The carbaalane halogen derivatives [(AlX)(6)(AlNMe3)(2)(CCH2CH2SiMe3)(6)] (X = F (9), Cl (7), Br (10), I (11)) were prepared in toluene from [(AlH)(6)(AlNMe3)(2)(CCH2CH2SiMe3)(6)] (6) and BF3.OEt2, BX3 (X = Br, I), Me3SnF, and Me3SiX (X = Cl, Br, I), respectively. A partially halogenated product [(AlH)(2)(AlX)(4)(AlNMe3)(2)(CCH2CH2SiMe3)(6)] (12) (X = Cl (similar to40%), Br (similar to60%)) was obtained from 5 and impure BBr3. [(AlH)(6)(AlNMe3)(2)(CCH2Ph)(6)] (5) was converted to [(AlX)(6)(AlNMe3)(2)(CCH2Ph)(6)] (X = F (13), Cl (14), Br (15), I (16)) using BF3.OEt2 and Me3SiX (X = Cl, Br, I), respectively. The X-ray single-crystal structures of 11.C6H6, 12.3C(7)H(8), 13.6C(7)H(8), and 15.4C(7)H(8) were determined. Compounds 7 and 9-11 are soluble in benzene/toluene and could be well characterized by NMR spectroscopy and MS (EI) spectrometry. The results demonstrate the facile substitution of the hydridic hydrogen atoms in 5 and 6 by the halides with different reagents.