摘要:
When treated with ultrasound, the reaction of ytterbium powder with INPPh3 in tetrahydrofuran leads to [YbI2(THF)(4)] and to the mixed-valence phosphoraneiminato complex [Yb2I(THF)(2)(NPPh3)(4)].2THF (1), which forms red single-crystals. In the analogous reaction in 1,2-dimethoxyethane (DME) only the ytterbium(II) iodide solvates [YbI2(HNPPh3)(DME)(2)] (2) and [{YbI2(DME)(2)}(2) (mu-DME)] (3) can be isolated, which form yellow single crystals. All compounds were characterized by crystal structure analyses.1: Space group P (1) over bar, Z = 2, lattice dimensions at -80 degrees C: a = 1337.6(5), b = 1389.6(5), c = 2244.2(17) pm; alpha = 86.11(7)degrees, beta = 88.06(7)degrees, gamma = 88.63(4)degrees; R = 0.0759. In 1 the two ytterbium atoms are connected via the N atoms of two phosphoraneiminato groups (NPPh3-) to form a planar Yb2N2 four membered ring. The structure can also be described as an ion pair consisting of [YbI(THF)(2)](+) and [Yb(NPPh3)(4)](-).2: Space group P2(1), Z = 2, lattice dimensions at -80 degrees C: a = 811.9(1), b = 1114.0(1), c = 1741.3(1) pm; beta = 95.458(5)degrees; R = 0.0246. 2 forms molecules in which the ytterbium atom is coordinated in a pentagonal-bipyramidal fashion with the iodine atoms in the axial positions. The O atoms of the two DME-chelates and the N atom of the phosphaneimine ligand HNPPh3 are in the equatorial positions.3. Space group P (1) over bar, Z = 2, lattice dimensions at -70 degrees C: a = 817.5(1), b = 1047.7(1), c = 1115.5(2) pm; alpha = 90.179(10)degrees, beta = 97.543(15)degrees, gamma = 91.087(12)degrees; R = 0.0317. 3 has a dimeric molecular structure, in which the two fragments {YbI2(DME)(2)} are connected centrosymmetrically via a mu-DME bridge. As in 2, the ytterbium atoms are coordinated in a pentagonal-bipyramidal fashion with the iodine atoms in the axial positions, as well as with the two DME chelates and with one O atom each of the mu-DME ligand in the equatorial positions.