RESUMO
The fluorescent ligand 1,1'-((1E,1'E)-(1,2-phenylenebis(azanylylidene))bis(methanylylidene)) bis(naphthalen-2-ol) (H2L) was used to prepare lanthanide(iii) metal complexes. These were found to self-assemble as triple decker sandwich complexes of the type (Ln2L3), where Ln = Pr(iii), Nd(iii), Sm(iii), Eu(iii), Gd(iii), Tb(iii), Dy(iii), Ho(iii), Er(iii), Yb(iii), or Lu(iii). The structures of the complexes Nd2L3, Gd2L3, Tb2L3, Dy2L3, Ho2L3, Yb2L3, and Lu2L3 are structurally characterized by single crystal X-ray diffraction. In the Nd2L3 complex, both metals are 8 coordinate. Yb2L3, Tb2L3, Dy2L3, and Lu2L3 are isostructural. In these, as in the Gd2L3 and Ho2L3 complexes, one metal is 8 coordinate, one 7 coordinate. The ligand was found to have tunable emission in the solid state across the lanthanide series with a maximum at 556 nm for the Sm2L3 complex to 617 nm for Er2L3. Of these, most demonstrate only ligand-centered fluorescence at room temperature. The ligand was found to have much greater fluorescence in the complex Lu2L3. Here, we describe these distinctive triple decker complexes and their absorption and emission properties as both solids and solutions.
RESUMO
The synthesis, characterization, and electronic spectroscopy of two ML2 sandwich complexes, where M = Ce(iv) or Th(iv) and L = napthylsalophen2- are described. The ThL2 complex, unlike the isovalent CeL2, complex possesses unusual fluorescence properties in both solution and solid-state. These observations are explained with TD-DFT.
RESUMO
Examples of compounds with gallium-boron donor-acceptor bonds, HC[MeC(2,6-pri2C6H3)N]2Ga-->B(C6F5)3 3 and (eta 5-C5Me5)Ga-->B(C6F5)3 4 have been prepared by treatment of the free gallanediyls with B(C6F5)3; the structures of both compounds were determined by X-ray crystallography.