Synthesis\nand Characterization of Solvated Lanthanide(II)\nBis(triisopropylsilyl)phosphide Complexes

Lanthanide (Ln) silylamide chemistry is well-developed,\nbut the\ncorresponding silylphosphide chemistry is immature; there are only\nten structurally characterized examples of Ln(II) bis(trimethylsilyl)phosphide\ncomplexes to date and no reported derivatives with bulkier R-groups.\nHere, we report the synthesis of the first f-block bis(triisopropylsilyl)phosphide\ncomplexes, [Ln{P(Si<sup><i>i</i></sup>Pr<sub>3</sub>)<sub>2</sub>}<sub>2</sub>(THF)<sub><i>x</i></sub>] (<b>1-Ln</b>; Ln = Sm, Eu, <i>x</i> = 3; Ln = Yb, <i>x</i> = 2), by the respective salt metathesis reactions of parent [LnI<sub>2</sub>(THF)<sub>2</sub>] with 2 equiv of [Na{P(Si<sup><i>i</i></sup>Pr<sub>3</sub>)<sub>2</sub>}]<sub><i>n</i></sub> in\ntoluene. Complexes <b>1-Ln</b> were characterized by a combination\nof NMR, EPR, ATR–IR, electronic absorption and emission spectroscopies,\nelemental analysis, SQUID magnetometry, and single crystal X-ray diffraction.\nThese data contrast with those obtained for related Ln(II) bis(trimethylsilyl)phosphide\ncomplexes due to the bulkier ligands in <b>1-Ln</b> and also\nwith Ln(II) bis(triisopropylsilyl)amide complexes due to a combination\nof longer Ln–P vs. Ln–N bonds and the softer nature\nof P- vs. N-donor ligands.