Synthesis, characterization and luminescence properties of LnIII (Ln = Eu, Tb, Ce, Sm, Dy) complexes containing a terpyridine ligand and a 3d–4f type conjugated terpyridine-alkyne bridging EuIII–Co0 carbonyl cluster complex

Abstract

Seven new organic trivalent lanthanide complexes containing a terpyridine or terpyridine-alkyne ligand, [Ln(L1)(CH3OH)(NO3)3] (Ln=Eu 1, Tb 2, Ce 3, Sm 4, Dy 5; L1=4-(4-bromophenyl)-2,2′:6′,2″-terpyridine) and [Ln(L2)(NO3)3] (Ln=Eu 6, Tb 7; L2=4-(4-trimethylsilyl phenylacetylene)-2,2′:6′,2″-terpyridine), were synthesized by the reaction of Ln(NO3)3·6H2O (Ln=Eu, Tb, Ce, Sm, Dy) with L1 and L2, respectively. In addition, a new 3d–4f type conjugated EuIII–Co0 carbonyl cluster complex, [(NO3)3Eu(η3-L2-μ)(Co2(CO)6)] 8, was obtained by the reaction of complex 6 with Co2(CO)8 in THF. All of these complexes were characterized and X-ray single-crystal diffraction reveals that the CeIII ion is ten-coordinated and lies approximately in the center of a polyhedron with 16 faces in the structure of complex 3. The molecular conformation is stabilized by intra- and intermolecular hydrogen bonds, and intermolecular π–Br and π–π interactions. The luminescence properties of these complexes were also investigated in the solid state.