Molecular architecture of polynuclear ruthenium bipyridyl complexes with controlled metal helicity

Di- and trinuclear ruthenium(II) complexes of the 'Chiragen' ligand series were synthesized. The results revealed that the reaction of the ligands with Ru(bpy)2Cl2 generates a mixture of diastereomers whereas the use of enantiomerically pure delta- or lamda-(Ru(bpy)2(py)2)(dibenzoyltartrate) or delta-Ru(CG(m-xyl))Cl2 yield products of nearly complete stereoselectivity. The results of a circular dichroism study also showed that the complexes consist of one helical diastereomer with the expected absolute configuration predetermined by the chiral building block used. C2 point group symmetry was the observed configuration of the structures.