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Phosphanimine and phosphoraneiminato complexes of beryllium. Crystal structures of [BeCl2(HNPPh3)2], [BeCl(HNPPh3)2(Py)]Cl, and [Be3Cl 2(NPPh3)4]
Neumueller, Bernhard,Dehnicke, Kurt
, p. 369 - 376 (2008/10/09)
Tetraphenylphosphonium hexachlorodiberyllate, (Ph4P) 2[Be2Cl6], reacts with lithium phosphoraneiminate, [LiNPPh3]6, in dichloromethane to give the three-nuclear beryllium phosphoraneiminate [Be3Cl 2(NPPh3)4] (3). As a by-product the phosphaneimine complex [BeCl2(HNPPh3)2] (1) can be isolated, which reacts with pyridine to give the ionic complex [BeCl(HNPPh3)2(Py)]Cl (2). On the other hand, the silylated phosphanimine Me3SiNP(p-tolyl)3 (5) does not react with BeCl2 or (Ph4P)2[Be 2Cl6] forming the expected phosphoraneiminates. From CH2Cl2 solutions only the amino-phosphonium salt [(C 7H7)3PNH2]Cl (4) can be obtained. The compounds 1-5 are characterized by single X-ray analyses and by IR spectroscopy. 1·C7H8: Space group C2/c, Z = 4, lattice dimensions at 193 K: a = 1408.9(2), b = 1750.9(2), c = 1633.2(2) pm, β = 106.50(1)°; R1 = 0.0385. 1 forms a molecular structure with short Be-N distances of 169.8(3) pm. 2·Py: Space group P, Z = 4, lattice dimensions at 193 K: a = 969.5(1), b = 2077.1(2), c = 2266.4(2) pm, α = 72.24(1)°, β = 87.16(1)°, γ = 77.42(2)°, R 1 = 0.0776. 2 forms ion pairs in which the NH atoms of the phosphaneimine ligands act as hydrogen bridges with the chloride ion. The HNPPh3 ligand realizes short Be-N bonds of 169.0(6) pm, the Be-N distance of the pyridine molecule is 182.5(6) pm. 3·3CH 2Cl2: Space group P, Z = 2, lattice dimensions at 193 K: a = 1333.2(2), b = 1370.2(2), c = 2151.8(3) pm, α = 107.14(1)°, β = 91.39(1)°, γ = 105.15(1)°, R1 = 0.0917. The structure of the three-nuclear molecule 3 corresponds with a Be2+ ion which is tetrahedrally coordinated by the nitrogen atoms of two {ClBe(NPPh 3)2}- chelates. 4·CH2Cl 2: Space group P21/c, Z = 4, lattice dimensions at 193 K: a = 1206.6(2), b = 1798.0(2), c = 1096.2(1) pm, β = 97.65(1)°, R 1 = 0.0535. 4 forms dimeric units in which the NH2 groups of the [(C7H7)3PNH2]+ cations act as hydrogen bridges with the chloride ions to give centrosymmetric eight-membered rings. 5: Space group P21/n, Z = 4, lattice dimensions at 193 K: a = 1074.3(2), b = 2132.2(3), c = 1075.5(2) pm, β = 110.68(1)°, R1 = 0.0664. 5 forms molecules with distances PN of 154.6(3), SiN of 168.8(3) pm, and bond angle SiNP of 134.4(2)°.
