[OMEGA-(PHOSPHANYL)ALKYL]CYCLOPENTADIENYL COMPLEXES

The syntheses and characterisation of the [omega-(phosphanyl)alkyl]cyclopentadienyl 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 detected by IR spectroscopy. The carbonyl chelate complexes are thermally stable. Under photochemical conditions, ligand exchange reactions are possible which in the case of 1,5-cyclooctadiene proceed with decomplexation of the phosphane arm. This does not prevent a reaction at the cobalt(I) atom; treatment of 35 with diphenylethyne gives the corresponding tetraphenylcyclobutadiene complex 36 in good yield, the phosphane arm remaining uncoordinated.