Structures and XPS studies of several 3d–4f cyano-bridged LnIII–FeIII/CoIII heterometallic complexes

Characterization and crystal structure determination of 3d–4f cyano-bridged bimetallic assemblies, Ln(DMF)4(H2O)3Co(CN)6 · H2O (DMF = N,N′-dimethylformamide, Ln = Tb, Dy, Ho and Er) have been newly carried out. We have observed their isostructural features and gradual decreasing cell constants and corresponding changes of local bond distances and angles around the cyano-bridges in accord with the ionic radii changes due to lanthanoid contraction. In order to elucidate the reasons that only Nd–Fe and Nd–Co complexes can exhibit photo-induced magnetic functions, we have also investigated the electronic properties for several analogous 3d–4f complexes, Ln(DMF)4(H2O)3M(CN)6 · H2O (Ln = Ce, Nd, Sm, Gd, Tb, Dy, Ho and Er; M = Co and Fe), by means of X-ray photoelectron spectroscopy (XPS). We found that the characteristic bent features of Nd–N–C bond angles and the slight shift of binding energies of Ln 4d3/2 peaks in the 3d–4f systems being closed to mixed-valence states might be the reasons for the novel functions.

We have newly carried out the crystal structure determination of several 3d–4f cyano-bridged bimetallic assemblies, Ln(DMF)4(H2O)3Co(CN)6 · H2O (DMF = N,N′-dimethylformamide; Ln = Tb, Dy, Ho and Er) and X-ray photoelectron spectroscopy (XPS) studies of several analogous 3d–4f complexes, Ln(DMF)4(H2O)3M(CN)6 · H2O (Ln = Ce, Nd, Sm, Gd, Tb, Dy, Ho and Er; M = Co and Fe) systematically. The results revealed that the reasons for photo-induced magnetization of NdIII–FeIII or CoIII complexes could be attributed to characteristic bent structures around cyano-bridges and gradual shifts of binding energies of Ln 4d3/2 peaks being closed to mixed-valence states.Figure optionsDownload as PowerPoint slide