Reactions of the stable bis(amino)silylene Si[{N(CH2tBu)}2C6H4-1,2] with group 3 or lanthanide metal organic compounds.: Crystal structures of [Ln(η5-C5H5)3Si{[N(CH2tBu)]2C6H4-1,2}]•C7H8 (Ln = Y or Yb)

Treatment of the thermally stable aminosilylene Si[{N(CH(2)tBu)}(2)C6H4-1,2] [= Si(NN)] with a tris(cyclopentadienyl)- group 3 or -lanthanide metal compound LnCp(3) (Cp = eta (5)-C5H5 and Ln = Y or Yb) in toluene at ambient temperature afforded the first earliest transition or f-block metal-silylene complexes [LnCp(3){Si(NN)}].C7H8 (Ln = Y (1) or Yb (2)), characterized by NMR spectroscopy and X-ray crystallography: complex 1 (monoclinic, space group P2(1)/c (no. 14), a = 15.641(5), b = 15.895(7), c = 14.876(5) +, beta = 112.93(3), Z = 4, R1 = 0.067 for 6194 observed data), and2 (monoclinic, space group P2(1)/c (no. 14), a = 15.635(3), b = 15.795(2), c = 14.842(2) A, beta = 112.87(2), Z = 4, R1 = 0.044 for 9829 observed data). The Ln atom in each of the isoleptic complexes 1 and 2 has distorted trigonal monopyramidal geometry, with the approximately trigonal silicon atom in the apical position. The Ln-Si bond length is 3.038(2) (1) or 2.984(2) A (2). Variable temperature Si-29{H-1} NMR spectra in toluene-d(8) show that each complex readily dissociates (Y > Yb) into its factors; at 188 K, the Si-29{H-1} signal for (1) was a doublet centred at delta 119.5, (1)J(Si-29-Y-89) = 59 Hz.