title: A series of pure-blue-light emitting Cu(i) complexes with thermally activated delayed fluorescence: structural, photophysical, and computational studies.
abstract: Four mononuclear Cu(i)-halide complexes containing phosphines and pyridine ligands with strong electron donor substituents, [CuCl(PPh3)2(4-NMe2py)] (1), [CuI(PPh3)2(4-NH2py)] (2), [CuI(POP)(4-NH2py)] (3), and [CuI(POP)(4-NMe2py)]·0.5(Et2O) (4), (PPh3= triphenylphosphine, 4-NMe2py = 4-(dimethylamino)pyridine, POP = bis[(2-diphenyl-phosphino)phenyl]ether, 4-NH2py = 4-aminopyridine, Et2O = diethyl ether) were synthesized and studied with regard to their structural, photophysical properties and theoretical calculations. The complexes exhibit pure blue thermally activated delayed fluorescence (λmax= 442 (1), 436 (2), 464 (3), and 448 nm (4)) in crystalline at room temperature. Emission lifetime analyses and density functional theory (DFT) calculations show that the blue-light emission at room temperature is the singlet (metal + halide)-to-ligand charge transfer state, (1(M + X)LCT), while that at 77 K is the state of3(M + X)LCT transition character, owing to the small singlet-triplet energy gaps (ΔE = 660-1680 cm-1). X-ray diffraction structure analysis, photophysical studies and theoretical calculations suggest that the much larger torsion angle between the N-heterocyclic rings and N-Cu-X planes of complex 3 than that of 1, 2 and 4 might causes the bathochromic shift of luminescence, although these complexes containing similar heterocycle ligands.
authors.affiliation: Institute of Optical Crystalline Materials, College of Chemistry, Fuzhou University, Fuzhou 350116, P. R. China. xhhuang@fzu.edu.cn.
authors.forename: Chun-Hua
authors.initials: CH
authors.lastname: Huang
authors.affiliation: Institute of Optical Crystalline Materials, College of Chemistry, Fuzhou University, Fuzhou 350116, P. R. China. xhhuang@fzu.edu.cn.
authors.forename: Meng
authors.initials: M
authors.lastname: Wen
authors.affiliation: Institute of Optical Crystalline Materials, College of Chemistry, Fuzhou University, Fuzhou 350116, P. R. China. xhhuang@fzu.edu.cn.
authors.forename: Chun-Ya
authors.initials: CY
authors.lastname: Wang
authors.affiliation: Institute of Optical Crystalline Materials, College of Chemistry, Fuzhou University, Fuzhou 350116, P. R. China. xhhuang@fzu.edu.cn.
authors.forename: Yong-Feng
authors.initials: YF
authors.lastname: Lu
authors.affiliation: Institute of Optical Crystalline Materials, College of Chemistry, Fuzhou University, Fuzhou 350116, P. R. China. xhhuang@fzu.edu.cn and State Key Laboratory of Photocatalysis on Energy and Environment, Research Institute of Photocatalysis, Fuzhou University, Fuzhou 350116, P. R. China.
authors.forename: Xi-He
authors.identifier: http://orcid.org/0000-0002-6919-0397
authors.initials: XH
authors.lastname: Huang
authors.affiliation: Institute of Optical Crystalline Materials, College of Chemistry, Fuzhou University, Fuzhou 350116, P. R. China. xhhuang@fzu.edu.cn.
authors.forename: Hao-Hong
authors.initials: HH
authors.lastname: Li
authors.affiliation: Institute of Optical Crystalline Materials, College of Chemistry, Fuzhou University, Fuzhou 350116, P. R. China. xhhuang@fzu.edu.cn.
authors.forename: Shu-Ting
authors.initials: ST
authors.lastname: Wu
authors.affiliation: Institute of Optical Crystalline Materials, College of Chemistry, Fuzhou University, Fuzhou 350116, P. R. China. xhhuang@fzu.edu.cn.
authors.forename: Nai-Feng
authors.initials: NF
authors.lastname: Zhuang
authors.affiliation: Institute of Optical Crystalline Materials, College of Chemistry, Fuzhou University, Fuzhou 350116, P. R. China. xhhuang@fzu.edu.cn.
authors.forename: Xiao-Lin
authors.initials: XL
authors.lastname: Hu