The initiation of ring-opening metathesis polymerisation of norbornadiene by seven-coordinate molybdenum(II) compounds. X-ray crystal structure of [Mo(μ-Cl)(SnCl3)(CO)3(η4-NBD)]

The new heterobimetallic complex [Mo(μ-Cl)(SnCl3)(CO)3(η4-NBD)] (1) has been prepared by reaction of [(CO)4Mo(μ-Cl)3Mo(SnCl3)(CO)3] with norbornadiene (NBD) at room temperature. The structure of complex 1 was established by X-ray crystallography. The IR, 1H- and 13C-NMR spectra of 1 are also described and can be correlated with the crystallographically observed geometry. In the presence of an excess of NBD compound 1 initiates the ring-opening metathesis polymerisation (ROMP). The initiation mechanism of ROMP by seven-coordinate molybdenum(II) compounds have been discussed. The microstructure of polynorbornadiene formed was determined by 1H- and 13C-NMR spectroscopy.