80594-62-3Relevant academic research and scientific papers
Trimethylsilyl halide adducts of dinuclear phosphine-bridged palladium halide complexes: Synthesis, spectroscopy, and reactions of Pd2X2(dppm)2·Me3SiX′ (X, X′ = Cl, Br, I)
Kirss, Rein U.
, p. 3451 - 3458 (2008/10/08)
Reaction of Pd2X2(dppm)2 (1, X = Cl; 2, X = Br; 3, X = I) with Me3SiX′ (X′ = Cl, Br, I) in dichloromethane produced transient dark green solutions for all combinations of X and X′ with the exception of X = X′ = Cl. Net halide exchange was observed for reactions of 1 with Me3SiBr or Me3SiI and for 2 with Me3SiI, apparently without oxidative addition of the silicon-halide bond. Mono- and dinuclear palladium complexes Pd2(μ-CH2)Cl2(dppm)2 (4) and PdCl2(dppm) (5) also exchanged Pd-Cl bonds for Pd-Br bonds in reactions with Me3SiBr. Low-temperature 1H and 31P NMR spectroscopy provided evidence for formation of adducts of formulas Pd2Cl2(dppm)2·Me3-SiCl, Pd2Br2(dppm)2·Me3SiCl, Pd2Br2(dppm)2·Me3SiBr, Pd2I2(dppm)2·Me3SiBr, and Pd2I2(dppm)2·Me3SiI in the reactions of 1-3 with Me3SiX′. Dark green solids of formula Pd2X2(dppm)2·Me3SiX′ (6: (a) X = Cl, X′ = I; (b) X = Br, X′ = I; (c) X = Br, X′ = Br; (d) X = Cl, X′ = Br; (e) X = I, X′ = Br; (f) X = I, X′ = I) could be isolated from the reaction mixtures. The green color is proposed to result from a weakening of the metal-metal bond in 1-3 upon coordination of the trimethylsilyl halide. The presence of oxygen in reactions of 1-3 with Me3SiX′ (X = Cl, Br, I) did not interfere with the formation of the adduct but led to the formation of siloxanes and mononuclear palladium complexes PdXX′(dppm). There was no evidence for Si-Si bond formation in these systems. Halide exchange was also observed in reactions of 1, 2, and 5 with methyl iodide.
