Novel 1,3,2-diazabora-[3]ferrocenophanes and a 1,4,2,3-diazadibora-[4]ferrocenophane

N,N′-Dilithiated 1,1′-bis(trimethylsilylamino)ferrocene (2) reacts with boron halide adducts (HBBr2–SMe2; BF3–OEt2 and BBr3–SMe2), boron halides (BCl3, BBr3, BCl2(OPh) and BCl2(Ph)) and 1,1-bis(dimethylamino)dichlorodiborane(4) to give the corresponding 1,3-bis(trimethylsilyl)-1,3,2-diazabora-[3]ferrocenophanes (3)–(8) and the 2,3-bis(dimethylamino)-1,4-bis(trimethylsilyl)-1,4,2,3-diazadibora-[4]ferrocenophane (9). All new complexes were characterised by multinuclear magnetic resonance spectroscopy in solution, and the solid-state molecular structures of the hydride (3), fluoride, chloride (4, 5), and of the phenoxy and phenyl derivatives (7, 8) were determined by X-ray analysis.