[OMEGA-(PHOSPHANYL)ALKYL]CYCLOPENTADIENYL COMPLEXES

The syntheses and characterisation of the [omega-(phosphanyl)alkyl]cyc lopentadienyl anions 2,3, 6-8, 10, and 11 are described. These anions form metallocenes 12-15 and 17-19 with FeCl2 . 2 THF and with ZrCl4 . 2 THF, respectively. With ICo(CO)4 chelated carbonyl complexes 23-25, 28, and 29 are formed. The unchelated intermediate 20 has been detecte d by IR spectroscopy. The carbonyl chelate complexes are thermally sta ble. Under photochemical conditions, ligand exchange reactions are pos sible which in the case of 1,5-cyclooctadiene proceed with decomplexat ion of the phosphane arm. This does not prevent a reaction at the coba lt(I) atom; treatment of 35 with diphenylethyne gives the correspondin g tetraphenylcyclobutadiene complex 36 in good yield, the phosphane ar m remaining uncoordinated.