1418274-98-2Relevant academic research and scientific papers
Phosphido-borane and phosphido-bis(borane) complexes of the alkali metals, a comparative study
Izod, Keith,Watson, James M.,Clegg, William,Harrington, Ross W.
, p. 1466 - 1475 (2013/04/10)
Treatment of the secondary phosphine {(Me3Si) 2CH}(Ph)PH with BH3·SMe2 yields the phosphine-borane {(Me3Si)2CH}(Ph)PH(BH3) (12) as colorless crystals. The reactions between 12 and n-BuLi, PhCH2Na or PhCH2K yield the corresponding phosphido-borane complexes [[{(Me3Si)2CH}(Ph)P(BH3)]Li(THF) 2]∞ (13), [{(Me3Si)2CH}(Ph) P(BH3)][Na(12-crown-4)2] (14), or [[{(Me 3Si)2CH}(Ph)P(BH3)]K(pmdeta)]2 (15), respectively, after crystallization in the presence of the appropriate co-ligand. While 13 crystallizes as a chain polymer, 14 crystallizes as a separated ion pair and 15 as a dimer. In both 13 and 15 the phosphido-borane ligands bind the alkali metal cations via both P-M and B-H·M contacts. Unexpectedly, NMR spectroscopy suggests that the separated ion pair 14 undergoes rapid inversion at phosphorus, while 13 and 15 do not. The phosphido- bis(borane) complexes [{(Me3Si)2CH}(Ph)P(BH 3)2]Li(12-crown-4) (16b), [[{(Me3Si) 2CH}(Ph)P(BH3)2]Na(THF)2] 2 (17), and [[{(Me3Si)2CH}(Ph)P(BH 3)2]K(THF)0.5]∞ (18a) were prepared by treatment of the corresponding in situ-generated phosphido-borane complexes with BH3·SMe2 and crystallization in the presence of the appropriate co-ligand. Compound 16b crystallizes as a monomer, while 17 crystallizes as a dimer and 18a crystallizes as a ribbon polymer. These crystallographic studies reveal entirely new binding modes for both phosphido-borane and phosphido-bis(borane) ligands and allow a direct comparison between these two ligand types.
