Contributions to the chemistry of phosphorus. 218. Monocyclic and polycyclic phosphines

Rare Earth Arene-Bridged Complexes Obtained by Reduction of Organometallic Precursors

“…Apparently, the tautomerization only takes place in highly ionic compounds such as Li3P7 and Cs3P7 (Kraus et al, 2003); no tautomerization was observed for silyl substituted P7R3 compounds (Baudler and Glinka, 1993).…”

“…P7 3-is the major product of P4 activation by strong reductants or nucleophiles as well as the "dead-end" of the decompositions of other polyphosphide species (Baudler and Glinka, 1993;Scheer et al, 2010). Intense experimental and theoretical studies have been performed on its alkali and alkali earth metal complexes.…”

“…Intense experimental and theoretical studies have been performed on its alkali and alkali earth metal complexes. For example, Li3P7 was studied by variable temperature and 2D 31 P NMR spectroscopy (Baudler et al, 1979;Baudler and Hahn, 1990), and it was found that the 31 P NMR spectrum of Li3P7 in THF-d8 is temperature dependent: at low temperature (-60 °C), three distinguishable signals were observed for the three different types of 66 phosphorus atoms in P7 3-; however, upon warming, coalescence took place and, eventually, at high temperature (50 °C) only one peak was observed. That phenomenon was attributed to a fluxional behavior of P7 3- (Baudler and Glinka, 1993).…”

“…For example, Li3P7 was studied by variable temperature and 2D 31 P NMR spectroscopy (Baudler et al, 1979;Baudler and Hahn, 1990), and it was found that the 31 P NMR spectrum of Li3P7 in THF-d8 is temperature dependent: at low temperature (-60 °C), three distinguishable signals were observed for the three different types of 66 phosphorus atoms in P7 3-; however, upon warming, coalescence took place and, eventually, at high temperature (50 °C) only one peak was observed. That phenomenon was attributed to a fluxional behavior of P7 3- (Baudler and Glinka, 1993). The free P7 3-anion can tautomerize to essentially the same tautomer (there are 1680 of them) (Baudler et al, 1979) by simultaneously breaking one Pbottom-Pbottom bond and forming a new P-P bond between two Pedge atoms right next to the two Pbottom atoms of the P-P bond that breaks.…”

“…Despite this difference in the coordination environment, P-P distances (listed in Table 3) followed a trend consistent with the size of the metal ion: the larger the rare earth, the shorter the Pedge-Pbottom distance. In alkali-earth metal stabilized P7 3-compounds, the three distinguishable P-P bonds also have different distances, with the shortest being the Pedge-Pbottom and the longest being the PbottomPbottom distance (Baudler and Glinka, 1993). For instance, in Sr3P14, Papex-Pedge, Pedge-Pbottom, and Pbottom-Pbottom are 2.21, 2.17, and 2.25 Å, respectively.…”