Synthesis, characterisation and stereochemistry of indenyl complexes of iridium(I) containing chiral diphosphines

Indenyl iridium(I) complexes of the type (eta(5)-C9H7)Ir(diphos) (diphos=PPh3, dppe, rac-cypenphos, (S,S)-chiraphos, (R)-prophos, (R,R)-renorphos and (R)-phenphos) have been synthesised by reacting (eta(5)-C9H7)Ir(C2H4)(2) with the appropriate diphosphine. The complexes show a dynamic behaviour in solution the energy barrier being in the range 8-13 kcal mol(-1) comparable with that observed for the corresponding rhodium(I) analogues. For complexes in which the diphosphine has a C-1 symmetry, the energy differences between the two diastereomeric conformations that are recognised at low temperature depend on the diphosphine used, not being substantially influenced by the metal centre.