title: Spectra, energy levels, and energy transition of lanthanide complexes with cinnamic acid and its derivatives.
abstract: High resolution spectra and luminescent lifetimes of 6 europium(III)-cinnamic acid complex {[Eu2L6(DMF)(H2O)]·nDMF·H2O}m (L=cinnamic acid I, 4-methyl-cinnamic acid II, 4-chloro-cinnamic acid III, 4-methoxy-cinnamic acid IV, 4-hydroxy-cinnamic acid V, 4-nitro-cinnamic acid VI; DMF=N, N-dimethylformamide, C3H7NO) were recorded from 8 K to room temperature. The energy levels of Eu(3+) in these 6 complexes are obtained from the spectra analysis. It is found that the energy levels of the central Eu(3+) ions are influenced by the nephelauxetic effect, while the triplet state of ligand is lowered by the p-π conjugation effect of the para-substituted functional groups. The best energy matching between the ligand triplet state and the central ion excited state is found in complex I. While the other complexes show poorer matching because the gap of (5)D0 and triplet state contracts.
authors.affiliation: College of Science, Chongqing University of Posts and Telecommunications, Chongqing 400065, China.
authors.forename: Kaining
authors.initials: K
authors.lastname: Zhou
authors.affiliation: College of Science, Chongqing University of Posts and Telecommunications, Chongqing 400065, China.
authors.forename: Zhongshan
authors.initials: Z
authors.lastname: Feng
authors.affiliation: College of Science, Chongqing University of Posts and Telecommunications, Chongqing 400065, China.
authors.forename: Jun
authors.initials: J
authors.lastname: Shen
authors.affiliation: College of Science, Chongqing University of Posts and Telecommunications, Chongqing 400065, China.
authors.forename: Bing
authors.initials: B
authors.lastname: Wu
authors.affiliation: College of Science, Chongqing University of Posts and Telecommunications, Chongqing 400065, China.
authors.forename: Xiaobing
authors.initials: X
authors.lastname: Luo
authors.affiliation: College of Science, Chongqing University of Posts and Telecommunications, Chongqing 400065, China.
authors.forename: Sha
authors.initials: S
authors.lastname: Jiang
authors.affiliation: College of Science, Chongqing University of Posts and Telecommunications, Chongqing 400065, China.
authors.forename: Li
authors.initials: L
authors.lastname: Li
authors.affiliation: College of Science, Chongqing University of Posts and Telecommunications, Chongqing 400065, China. Electronic address: zhouxj@cqupt.edu.cn.
authors.forename: Xianju
authors.initials: X
authors.lastname: Zhou
keywords: Cinnamic acid; Energy level; Lanthanide complex; Luminescence; Triplet-state