Organolanthanoids XXIII complexes of tris(cyclopentadienyl)lanthanoids with tertiary phosphine oxides and the X-ray crystal structures of [YbCp3(OPPh3)] and [NdCp3(OPBun3)]

Treatment of [LnCp3(THF)] (Ln=La, Nd, Sm, or Yb) (Cp, cyclopentadienyl and THF, tetrahydrofuran) and [Nd(MeCp)3(THF)] (MeCp, methylcyclopentadienyl) with OPR3 (R=Ph, o-tolyl, Bun) in either THF or DME (DME, 1,2-dimethoxyethane) gave the complexes [LnCp3(OPPh3)] (Ln=La, Nd, Sm and Yb), [Nd(MeCp)3(OPPh3)], [SmCp3(OP(o-tolyl)3)], [Nd(MeCp)3(OP(o-tolyl)3)], and [LnCp3(OPBun3)] (Ln=La, Nd). An attempt to react [GdCp3(THF)] with OPPh3 in either THF or DME crystallised unsolvated GdCp3, whilst a mixture of [GdCp3(OPPh3)] and OPPh3 was recovered from the filtrate. Attempted synthesis of [YbCp3(OPBun3)] yielded [{YbCp2(OPBun3)}2O], the connectivity established by X-ray crystallography, and impure [YbCp3(OPBun3)]. Single crystal X-ray structure determination of [YbCp3(OPPh3)] (monoclinic, space group P21, a=8.4187(7), b=17.019(11), c=9.450(7) A, β=97.97(6)°, Z=2, R=0.043 for 1576 observed data) showed the complex to contain formal ten coordinate ytterbium with distorted pseudo tetrahedral stereochemistry whilst the structure of [NdCp3(OPBun3)] (trigonal, space group P31/c, a=b=12.973(4), c=9.657(6) A, Z=2, R=0.052 for 602 observed data) showed ten coordinate neodymium with a distinctly trigonal pyramidal arrangement of oxygen and the centroids (Ct) of the Cp rings (Ct–Nd–Ct 119.8°).