NEW HYDROGEN-CONTAINING ZIRCONIUM CLUSTERS WITH PHOSPHINE LIGANDS

Abstract Reaction of ZrCl4 with 2 equiv. of HSnBu3 followed by addition of phosphines yields hexazirconium cluster compounds [Zr6Cl14H4(PR3)4] (2a: PR3 = PMe2Ph; 2b: PR3 = PEt2Pgh; 2c: PR3 = PEt3) and pentazirconium cluster compounds [Zr5Cl12H4(PR3)5] (3a:PR3 = PMe2Ph; 3c; PR3 = PEt2). Treatment of compound 2a with Na/Hg in the presence of PMe2Ph results in the formation [Zr6Cl12H2(PMe2Ph)6] (4a). When the phosphine ligand is PEt3, a similar reaction leads to the isolation of two new cluster compounds, [Zr6Cl12H3(PEt3)6][ZrCl5(PEt3)] (5c) and [Zr6Cl13H3(PEt3)5] (6c). In MeCN solution, compound 2a decomposes to form an ionic cluster compound, [HPMe2Ph]4[Zr6Cl18H4] (7a). Cluster hydrogen atoms were observed by 1H NMR spectroscopy for all cluster compounds and by X-ray diffraction study for compound 3c where two hydrogen atoms ate μ3-bridging and the other two edge-bridging. In compound 7a, there is evidence for the hydrogen atoms distributed near the centers of the one of the eight triangular faces of the Zr6 octahedron. When ZrCl4 reacts with 1 equiv. of HSnBu3 followed by addition of PR2Ph, only dinuclear compounds [Zr2Cl4(μ-Cl)2(PR2Ph)4] (8a: R = Me; 8b; R = Et) are isolated. All compounds were characterized by X-ray crystallography and 1H NMR spectroscopy. Compound 2a∗d0.75CH2Cl2 crystallized in the monoclinic space group C2/c with cell dimensions (−100°C) of a = 31.434(9), b = 15.255(6), c = 14.582(8) A , β = 106.08(2)°, V = 6719(9) A 3 and Z = 4. Compound 2b∗d2CH2Cl2 crystallized in the monoclinic space group P21/c with cell dimensions (−60°C) of a = 11.310(1), b = 17.412(5), c = 17.807(2) A , β = 91.55(1)°, V = 3505(1) A 3 and Z = 2. Compound 2c∗d2C6H6 crystallized in the monoclinic space group P21/n with cell dimensions (−150°C of a = 15.322(6), b = 12.186(3), c = 16.969(7) A , β = 91.09(2)°, V = 3117(2) A 3 and Z = 4. Coumpound 2c crystallized in the monoclinic space group C2/c with cell dimensions (−150°C) of a = 26.128(9), b = 16.826(1), c = 13.411(4) A , β = 117.07(1)°, V = 5250(2) A 3 and Z = 4. Compounds 3c∗dC6H5CH3 crystallized in the monoclinic space group C2/c with cell dimensions (−75°C) of a = 48.06(1), b = 12.667(3), c = 22.829(5) A , β = 113.36(2)°, V = 12758(5) A 3 and Z = 8. Compound 4a crystallized in the triclinic space group P 1 with cell dimensions (−60°C) of a = 12.918(3), b = 15.493(2), c = 18.90(1) A , α = 90.31(6), β = 104.37(2), γ = 109.89(3)°, V = 3429(2) A 3 and Z = 2. Compound 5c∗d0.5C6H6 crystallized in the monoclinic space group P2/c with cell dimensions (−60°C) of a = 23.707(6), b = 14.521(2), c = 25.109(3) A , β = 92.08(1)°, V = 8633(3) A 3 and Z = 4. Compound 6c∗dC6H6 crystallized in the orthorhombic space group Pna2t with cell dimensions (−100°C) of a = 23.496(9), b = 23.973(2), c = 11.638(1) A , V = 6555(3) A 3 and Z = 4. Compound 7a∗d2MeCN crystallized in the triclinic space group P 1 with cell dimensions (20°C) of a = 12.881(2), b = 22.859(3), c = 12.208(2) A , α = 98.6614(1), β = 109.99(1), γ = 81.39(1)°, V = 3320.8(9) A 3 and Z = 2. Compounds 8b∗d0.67C6H5CH3 crystallized in the rhombohedral spacve group r 3 m with cell dimensions (−100°C) of a = 20.947(3), b = 20.947(3), c = 30.87(1) A , V = 11730(4) A 3 and Z = 6.