Bis(cyclopentadienyl)yttrium complexes of the ligand [N(QPPh₂)₂]^- (Q = S, Se): synthesis, structure, and NMR properties of Cp₂Y[η³-N(QPPh₂)₂]

The compounds Cp₂Y[η³-N(QPPh₂)₂] (Q = S (1), Se (2)) have been synthesized in good yield from the protonolysis reaction between Cp₃Y and HN(QPPh₂)₂ in tetrahydrofuran. In both compounds, the [N(QPPh₂)₂]^- ligand is bound η³ to the Y center which, in 1, represents the first example of that mode of binding for the sulfur-containing ligand. The Y atom is also coordinated to two (C₅H₅)^- ligands and so is formally 9-coordinate. Both 1 and 2 are stable in inert environments for prolonged periods of time. Each is soluble in THF and CH₂Cl₂. ¹H, ³¹P, ⁷⁷Se, and ⁸⁹Y NMR data were collected to lend insight into the solution properties of these molecules. Crystallographic data for 1 (-120 °C): C₃₄H₃₀NP₂S₂Y, triclinic, P1̄, a = 9.685(5) Å, b = 12.176(6) Å, c = 13.978(7) Å, α = 87.382(9)°, β= 87.358(9)°, γ = 68.689(9)°, V = 1533(1) ų, Z = 2, and R₁(F) = 0.047 for the 4023 reflections with I > 2σ(I). Crystallographic data for 2 (-120 °C): C₃₄H₃₀NP₂Se₂Y, triclinic, P1̄, a = 9.745(5) Å, b = 12.222(6) Å, c = 13.930(7) Å, α = 88.024(9)°, β= 87.380(9)°, γ = 69.137(9)°, V = 1548(1) ų, Z = 2, and R₁(F) = 0.056 for the 4324 reflections with I > 2σ(I).