Pentamethylcyclopentadienyl ruthenium(II) complexes containing chiral diphosphines: Synthesis, characterisation and electrochemical behaviour. X-ray structure of (η5-C5Me5)Ru(S,S)-Ph 2PCH(CH3)CH(CH3)PPh;2Cl

Some pentamethylcyclopentadienyl ruthenium(II) diphosphine chloride complexes have been prepared by ligand exchange starting with the parent triphenylphosphine derivatives and their reactivities compared with those of the corresponding cyclopentadienyl compounds. The pentamethyl ligand causes a greater extent of asymmetric induction when the (R)-prophos and (R)-phenphos ligands are used as well as a higher lability of the stereochemistry at the stereogenic ruthenium centre. A shift of about 200 mV in the oxidation potential is caused by the substitution at the penta-hapto ligand. The order of basicity of the diphosphine ligands was also evaluated and was found to be consistent with previous determinations. The crystal structure of (η5-C5Me)Ru(S,S)-chiraphosC1 shows a coordination around the ruthenium atom similar to that found for the (η5-C5H5)Ru(S,S)-chiraphosCl complex. © 1998 Elsevier Science S.A. All rights reserved.