Luminescent metal complexes. 4—13C NMR spectra of the tris chelates of substituted 2,2′‐bipyridyls and 1,10‐phenanthrolines with ruthenium(II) and osmium(II)

Abstract 13 C Chemical shifts are reported for the ruthenium(II) tris complexes of thirteen 2,2′‐bipyridyls and three 1,10‐phenanthrolines and for the osmium(II) tris complexes of five 2,2′‐bipyridyls. Chelation induced shifts (δ complex – δ ligand ) are discussed in terms of models for π back‐bonding. 13 C NMR is shown to be a convenient tool for the direct observation of the geometrical isomerism of complexes formed from monosubstituted ligands.