Dipodal ligands from chiral spiro[2.4]hepta-4,6-dienes: solid state conformational effects by tether substitution in dipodal η5,η1-CpP–ruthenium(II) complexes

New chiral spiro[2.4]hepta-4,6-dienes were prepared and used in an efficient synthesis of cyclopentadienyl ruthenium complexes with pendant phosphine donors. Solid state structures reveal a conformation trend among three structurally homologous complexes that involves subtle twisting about the tether with increasing substitution at the alpha carbon. These results suggest architectural requirements for future ligand designs.