Synthesis of mixed phospholyl/cyclooctatetraenyl–lanthanide complexes. Crystal and molecular structure of (cyclooctatetraenyl)[3,4-dimethyl-2,5-bis(trimethylsilyl)-phospholyl](tetrahydrofuran)neodymium

New mixed phospholyl/cyclooctatetraenyl lanthanide complexes have been prepared by metathesis of phospholylpotassium salts with cyclooctatetraenyllanthanide halide precursors: [(cot)Sm(Tmp)(THF)] (5), [(cot)Sm(Dsp)] (6), and [(cot)Nd(Dsp)(THF)] (7) have been thus prepared (cot=cyclooctatetraenyl, Tmp=2,3,4,5-tetramethylphospholyl, Dsp=3,4-dimethyl-2,5-bis(trimethylsilyl)-phospholyl). Complex 7 has been structurally characterised. Formation of 5 has also been observed in the reaction of [(Tmp)2Sm] with cyclooctatetraene. An alternative synthesis of the [{(cot)SmCl(THF)}2] precursor has been reported, and the X-ray crystal structure of this complex determined.