N-Heterocyclic Tetrylenes with a 1,1′-Ferrocenylene Backbone and Bis(2,4,6-triisopropylphenyl)boryl N-Substituents

The diaminoferrocene derivative fc[NH(BTrip2)]2 (1H2; fc = 1,1′-ferrocenylene, Trip = 2,4,6-triisopropylphenyl) was prepared from fc(NH2)2 and Trip2BF and used for the preparation of the N-heterocyclic tetrylenes fc{[N(BTrip2)]2E} (1E, E = Ge, Sn, Pb) via the TMEDA-coordinated lithium amide 1Li2(TMEDA)2 (TMEDA = N,N,N′,N′-tetramethylethylenediamine). The N-heterocyclic plumbylene fc{[N(BMes2)]2Pb} (2, Mes = mesityl), which was obtained analogously, reacts with 4-(dimethylamino)pyridine (DMAP) to afford the adduct fc{N(BMes2)]2Pb(DMAP)} (3). No reaction with DMAP was observed with the sterically more congested plumbylene 1Pb. 1Pb and 2 both undergo immediate ammonolysis with NH3. All new compounds were structurally characterised by single-crystal X-ray diffraction.