Enhanced Luminescence of Asymmetrical Seven‐Coordinate EuIII Complexes Including LMCT Perturbation. Issue 32 (31st August 2017)

• Record Type: Journal Article
• Authors: Yanagisawa, Kei; Kitagawa, Yuichi; Nakanishi, Takayuki; Akama, Tomoko; Kobayashi, Masato; Seki, Tomohiro; Fushimi, Koji; Ito, Hajime; Taketsugu, Tetsuya; Hasegawa, Yasuchika
• Is Part Of: European journal of inorganic chemistry. Issue 32(2017)
• Page Start: 3843
• Page End: 3848
• Publication Date: 2017-08-31
• Subjects: Lanthanides -- Luminescence -- Charge transfer -- Structure elucidation -- Density functional calculations; Chemistry, Inorganic -- Periodicals; Organometallic chemistry -- Periodicals; Bioinorganic chemistry -- Periodicals; Solid state chemistry -- Periodicals; 546
• DOI: 10.1002/ejic.201700815
• Languages: English
• ISSNs: 1434-1948

Abstract

Abstract : Luminescent mononuclear seven‐coordinate Eu III complexes, with monocapped‐octahedral (point group: C 3 v ), monocapped‐trigonal‐prismatic ( C 2 v ), and pentagonal‐bipyramidal ( D 5 h ) coordination structures, are reported. The complexes each consist of a Eu III ion, three tetramethylheptanedionates, and a phosphine oxide derivative. Controlling steric hindrance by means of introducing methyl groups into the phosphine oxide ligands resulted in the formation of three types of coordination polyhedral structures. The coordination geometrical structures of the Eu III complexes were evaluated by single‐crystal X‐ray diffraction analysis and shape‐factor calculations. The radiative rate constant of the Eu III complex with a monocapped‐octahedral structure was larger than those with monocapped‐trigonal‐prismatic and pentagonal‐bipyramidal structures. Characteristic photophysical properties of the seven‐coordinate Eu III complexes are discussed with TD‐DFT calculations and Arrhenius analysis of the ligand‐to‐metal charge transfer. Abstract : Three types of coordination geometrical structures – monocapped octahedron, monocapped trigonal prism, and pentagonal bipyramid – were observed in Eu III complexes constructed by β‐diketonate and phosphine oxide ligands. The characteristic photophysical properties involving LMCT perturbation are discussed.