Palladium-Mediated Substitution Reactions of Polyhedral Borane Anions

Synthesis and X-ray structural characterization of the triphenylphosphine derivative of the closo-dodecaborate anion, closo-[B12H11P(C6H5)3][N(n-C4H9)4]

“…The signal at À17.9 ppm, corresponding to the boron atom bearing the triphenylphosphine group, appears as a doublet due to the coupling with the phosphorus atom (J B-P = 134 Hz). These data are consistent with those reported by Todd and co-workers [25] concerning the chargecompensated cluster 1,7-(PMe 2 Ph) 2 -B 12 H 10 . Consistently, the 31 P NMR spectrum of 2 shows only one quartet centered at 6.8 ppm.…”

“…These multiplets were attributed to the phenyl hydrogen atoms of the triphenylphosphine pendant group. These data are in good agreement with those reported for 1,7-(PMe 2 Ph) 2 -B 12 H 10 [25]. It is interesting to notice that the chemical shifts measured for the phenyl hydrogen atoms of 2 are shifted compared to those of triphenylphosphine (7.1-7.9 ppm) and closer to those of tetraphenylphosphonium bromide (7.6-7.9 ppm), the phosphorus atom of 2 being tetravalent.…”

“…For the preparation of neutral (PMe 2 Ph) 2 B 12 H 10 from [B 12 H 12 ] 2À , Todd and co-workers [25] have also suggested a two-step mechanism involving the formation of PdLBH four-centered intermediate. We assume that using the monoiodo derivative 1 as starting compound and palladium (0) complex as catalyst, instead of L 2 Cl 2 Pd (II), permit to preclude any direct reaction involving BH unit and yield selectively monosubstituted derivative.…”

“…0022-328X/$ -see front matter Ó 2005 Elsevier B.V. All rights reserved. doi:10.1016/j.jorganchem.2005.01.045More recently, Todd and co-workers[25] have shown that the reaction of [B 12 H 12 ]Li 2 with (PMe 2 Ph)…”

Unusual Cationic Tris(Dimethylsulfide)-Substituted closo-Boranes: Preparation and Characterization of [1,7,9-(Me2S)3-B12H9] BF4 and [1,2,10-(Me2S)3-B10H7] BF4

“…A 0.2069 g portion of pure product was obtained (0.667 mmol, 67%). 11 Workup procedures were common to both methods. The reaction flask was removed from the heat source and allowed to cool to ambient temperature.…”