title: Eu(III) emission band changes caused by peripheral C-H/O hydrogen bonding.
abstract: We synthesized Eu(III) and Sm(III) complexes with tridentate phosphine oxide ligands, Eu(hfa)(3)(TPPM) and Sm(hfa)(3)(TPPM) (hfa: hexafluoroacetylacetonato, TPPM: tris(diphenylphosphinyl)methane), and we then examined their luminescent properties. In the complexes the Eu(III) and Sm(III) centres were fully surrounded by low-vibrational frequency ligands, which led to relatively high emission quantum yields (Φ(Eu) = 30%, Φ(Sm) = 4.7%). The X-ray single crystal structures of the Eu(hfa)(3)(TPPM) revealed nona-coordinated Eu(III) complexes and C-H/O hydrogen bonding formations between the acidic hydrogen atom of the TPPM ligand and oxygen atoms of solvent molecules. The C-H/O hydrogen bonding slightly affected the coordination structure around the Eu(III) ion. Despite the seemingly small effect on the structural change, because the emission band profile of the (5)D(0)→(7)F(2) transition is sensitive to changes in the coordination environment of the Eu(III) complex, we observed a red shift in the emission spectral line.
authors.affiliation: Graduate School of Materials Science, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, Nara 630-0101, Japan. kuramo@kitasato-u.ac.jp
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Kuramochi
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Nakagawa
authors.forename: Toshiaki
authors.initials: T
authors.lastname: Yokoo
authors.forename: Junpei
authors.initials: J
authors.lastname: Yuasa
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Kawai
authors.forename: Yasuchika
authors.initials: Y
authors.lastname: Hasegawa
mesh_terms: D005063:Europium / Q000737:chemistry*; D006860:Hydrogen Bonding; D008024:Ligands; D008163:Luminescent Measurements; D008958:Models, Molecular; D008968:Molecular Conformation; D009942:Organometallic Compounds / Q000138:chemical synthesis / Q000737:chemistry*; D012493:Samarium / Q000737:chemistry
chemical_list: D008024:Ligands; D009942:Organometallic Compounds; D012493:Samarium; D005063:Europium