Synthese und Kristallstrukturen der Palladium(II)-Komplexe cis- und trans-PdCl₂[P(OSiMe₃)₃]₂, {PdCl[PO(OSiMe₃)₂][P(OSiMe₃)₃]₂} und (NMe₂H₂)₂{Pd₂Cl₄[P₄O₅(OSiMe₃)₄]} / Synthesis und Crystal Structures of the Palladium(II) Complexes cis- and trans-PdCl₂[P(OSiMe₃)₃]₂, {PdCl[PO(OSiMe₃)₂][P(OSiMe₃)₃]₂} and (NMe₂H₂)₂{Pd₂Cl₄[P₄O₅(OSiMe₃)₄]}

Abstract

The molecular complex PdCl 2 [P(OSiMe 3 ) 3 ] 2 was obtained both as cis- (la) and trans- (lb) isomer from palladium(II) chloride with the equivalent amount of tris(trimethylsilyl)phosphite in a THF suspension at room temperature. With excess P(OSiMe 3 ) 3 the complex {PdCI[PO(OSiMe 3 ) 2 ][P(OSiMe 3 ) 3 ] 2 } (2) is formed with elimination of trimethylchlorosilane. By partial hydrolysis the anionic binuclear palladium complex (NMe 2 H 2 ) 2 {Pd 2 Cl 4 [P 4 O 5 (OSiMe 3 ) 4 ]} (3) is generated from palladium(II) chloride and excess P(OSiMe 3 ) 3 in THF in the presence of dimethylamine. All complexes form colourless, moisture-sensitive crystals, which were characterized by X-ray structure determinations. 1a: Space group C2/c, Z = 4,2973 observed unique reflections, R = 0.044. Lattice dimensions at —80°C: a =1052.9(2), b =1675.3(5), c = 2240.1(7) pm, β = 99.88(2)°. The compound has a molecular structure with cis-arrangement of the P(OSiMe 3 ) 3 groups with Pd—P bond lengths of 222.9 pm. 1b: Space group P1̄, Z = 1, 3796 observed unique reflections, R = 0.053. Lattice dimensions at-70°C: a = 959.5(2), b = 998.3(2), c =1162.6(2) pm, α=86.99(3)°, β = 81.63(3)°, γ = 62.91(3)°. The compound has a molecular structure with trans-arrangement of the P(OSiMe 3 ) 3 groups with Pd—P bond lengths of 230.4 pm. 2: Space group P2 1 2 1 2 1 , Z = 4,4444 observed unique reflections, R = 0.055. Lattice dimensions at —70°C: a =1050.0(2), b = 2090.5(3), c = 2357.8(6) pm. The complex has a molecular structure with trans-arrangement of the P(OSiMe 3 ) 3 groups with Pd — P bond lengths of 233.6 and 232.1 pm. The Pd—P bond length of the [PO(OSiMe 3 ) 2 ]- ligand is 224.8 pm. 3: Space group P1̄, Z = 2,4762 observed unique reflections, R = 0.071. Lattice dimensions at —80°C: a = 1169.3(6), b = 1299.6(6), c = 1641.7(12) pm, α = 69.19(4)°, β = 87.37(5)°, γ = 80.01(4)°. In the dimeric anion {Pd 2 Cl 4 [P 4 O 5 (OSiMe 3 ) 4 ]} 2 - the two cis-PdCl 2 units are bridged by the four phosphorus atoms of the [P 4 O 5 (OSiMe 3 3 ) 4 ] 2- ligand with average Pd— P bond lengths of 221.5 pm.