NEW OBSERVATIONS ON DICYCLOPENTADIENYLMOLYBDENUM COMPLEXES DERIVED FROM DIMETHYL ACETYLENEDICARBOXYLATE. CRYSTAL STRUCTURE OF 5-C5H5)2MoOC(O)CH=CCO2CH3>

Article abstract of DOI:10.1016/S0022-328X(00)99681-5

Addition of chloroform to a solution of (η-C5H5)2MoH2 and dimethylacetylenedicarboxylate (CH3CO2C<*>CCO2CH3) in THF at 0 deg C gives two new complexes: (i) chloro-?-alkenyl (η⁵-C5H5)2MoCl and (ii) metallacyclic <(η⁵-C5H5)2MoOC(O)CH=CCO2CH3>.An X-ray diffraction study of the latter product revealed the presence of one water molecule per one organometallic molecule in the unit cell: space group P2₁, a 12.111(9), b 7.374(2), c 7.830(5) Angstroem, β 93.43(4) deg, Z = 2.The Mo-C bond length is 2.180(6) Angstroem.A mechanism involving an intramolecular elimination of CH4 from the initially formed insertion product (η⁵-C5H5)2MoH is proposed for its formation.