Funktionelle trimethylphosphanderivate: XIX. Phosphinomethylsubstituierte zirconiuimverbindungen als nucleophile: Synthese, reaktion mit CO und molekülstruktur von [(C 5H 5) 2Zr(CH 2PMe 2) 2] 2Ni

Abstract

The organozircomum-substituted phosphines Cp 2Zr(X)CH 2PMe 2 (Cp = η 5-C 5H 5; X = Cl, CH 2PMe 2) have been prepared from Cp 2ZrCl 2 and LiCH 2PMe 2. In these compounds, the phosphinomethyl group acts as a monohapto (η 1-) ligand. On reaction with CO, the bis(phosphinomethyl)zirconium complex forms a red complex, which by means of NMR spectroscopy is shown to contain a novel zircona heterocycle. With Ni(COD) 2, Cp 2Zr(CH 2PMe 2) 2 forms the 2:1 complex [Cp 2Zr(CH 2PMe 2) 2] 2Ni. Crystals (from tetrahydrofuran) are triclinic, space group P 1 , with parameters a 13.433(5), b 18.062(3), c 19.505(2) Å, α 64.35(2), β 76.82(1), γ 71.28(2)°, V 4018.12 Å 3, d x 1.445 g cm −3 for Z = 4, μ(Mo- K α) 11.5 cm −1, T 21°C. Refinement of 743 parameters on 8826 reflections converged at R = 0.055. The molecular structure consists of monomeric units with two bidentate C 2Zr(CH 2PMe 2) 2 molecules acting as chelating ligands to a tetrahedral Ni 0 centre. The six-membered Zr(CH 2PMe 2) 2Ni rings adopt a chair conformation. Steric strain by interaction of the axial cyclopentadienyl and methyl ligands at Zr and P, respectively, causes these rings to be considerably flattened.