PREPARATION AND SOME PROPERTIES OF CYCLOPENTADIENYLCOBALT(I)-OLEFIN COMPLEXES

Article abstract of DOI:10.1016/S0022-328X(00)86851-5

Cyclopentadineylcobalt(I) olefin complexes, (η⁵-C5H5)Co(L)(olefin) were prepared by reactions of (η⁵-C5H5)Co(L)2 (I) with olefins having electron-withdrawing groups.In the reaction of fumaronitrile with Ia (L=PPh3) the maleonitrile complex (IIe) was obtained together with the fumaronitrile complex (IId).The phosphine ligand of (η⁵-C5H5)Co(PPh3)(olefin) (II) was readily displaced by isocyanides to afford (η⁵-C5H5)Co(CNR)(olefin) (IV).In the cases of the cis-olefin complexes the presence of two conformational isomers (A and B) was observed, and their structures were assigned by the 1H NMR spectra.From the ratio of the isomers relative bulkiness of ligands around the cobalt atom was estimated.The bulkiness decreases in the order: triphenylphosphine > η⁵-cyclopentadienyl > isocyanide > carbon monoxide.