title: Emission properties and Cu(i)-Cu(i) interaction in 2-coordinate dicopper(i)-bis(N-heterocyclic)carbene complexes.
abstract: The synthesis, characterization, and emission properties of 2-coordinate dicopper(i) complexes bearing two trimethylene-bridged bis-NHC ligands, [Cu2(L3Me)2](PF6)2 (1), [Cu2(L3Et)2](PF6)2 (2), [Cu2(L3Bu)2](PF6)2 (3), [Cu2(L3MeOPh)2](PF6)2 (4) and [Cu2(L3Mes)2](PF6)2 (5), where L3R denotes trimethylene-bridged bis(N-heterocyclic)carbene (NHC) ligand substituted by two R groups at the nitrogen atoms of NHC, have been investigated. The quantum yield, Φ, and the lifetime, τ, of the emission of 2, are 0.21 and 25 μs, respectively in methanol, which is a well-known solvent for quenching the luminescence of many copper(i) complexes. The 8-shaped geometry of the dicopper(i) complexes brings a considerable copper(i)-copper(i) interaction which affects the luminescent properties. Additionally, we find that methoxyphenyl and mesityl groups substituted at the nitrogen atom of the NHC moiety drastically stabilize the bis(NHC) copper(i) complexes even in air-saturated acetone-d6.
authors.affiliation: Department of Materials and Life Science, Seikei University, Kichijoji-kitamachi, Musashino, Tokyo 180-8633, Japan. tsubomura@st.seikei.ac.jp.
authors.forename: Michihiro
authors.initials: M
authors.lastname: Nishikawa
authors.affiliation: Department of Materials and Life Science, Seikei University, Kichijoji-kitamachi, Musashino, Tokyo 180-8633, Japan. tsubomura@st.seikei.ac.jp.
authors.forename: Taichi
authors.initials: T
authors.lastname: Sano
authors.affiliation: Department of Materials and Life Science, Seikei University, Kichijoji-kitamachi, Musashino, Tokyo 180-8633, Japan. tsubomura@st.seikei.ac.jp.
authors.forename: Masaya
authors.initials: M
authors.lastname: Washimi
authors.affiliation: Research Laboratory for Nuclear Reactors, Tokyo Institute of Technology, 2-12-1 Ōokayama, Meguro-ku, Tokyo 152-8550, Japan.
authors.forename: Koichiro
authors.initials: K
authors.lastname: Takao
authors.affiliation: Department of Materials and Life Science, Seikei University, Kichijoji-kitamachi, Musashino, Tokyo 180-8633, Japan. tsubomura@st.seikei.ac.jp.
authors.forename: Taro
authors.initials: T
authors.lastname: Tsubomura