Synthesis and molecular structure of lanthanum tris[cyclopentadienylmolybdenotricarbonylate] tetrahydrofuranate, (THF)5La[CpMo(CO)3]3 · THF

Abstract The interaction of activated La powder with [CpMo(CO) 3 ] 2 or Hg[CpMo(CO) 3 ] 2 in THF resulted in the formation of crystalline (THF) 5 La[CpMo(CO) 3 ] 3 · THF (I), which oxidized readily on exposure to air with cleavage of [CpMo(CO) 3 ) 2 . Complex I was characterized by X-ray structural analysis. The La atom is bound to three equivalent CpMo(CO) 3 fragments via almost linear carbonyl bridges, MoCOLa (MoCO 177.9(7)°). The coordination of La with the terminal CO group (LaO av 2.444(5) A) leads to elongation of the CO bond from an average value of 1.16(1) to 1.21(1) A, and to shortening of the MoC bond from an average value of 1.943(9) to 1.874(9) A, compared with the unbridged CO. The coordination of La is complemented to CN = 8 at the expense of binding of five THF molecules (LaO(THF) av = 2.580(6) A; the sixth THF molecule is crystallizable).