title: Dual emission behavior of phenyleneethynylene gold(I) complexes dictated by intersystem crossing: a theoretical perspective.
abstract: In commonly studied gold(I) complexes with oligo (o-, p-, or m-phenyleneethynylene) (PE) ligands, an intriguing photophysical behavior is dual emission composed of fluorescence from S1 and phosphorescence from T1 which is dictated by effective intersystem crossing (ISC) process. In order to explore the salient photodynamics of such oligo-PE gold(I) complexes effectively, we have deliberately chosen three model complexes, namely, Ph-C≡C-Au(PMe3) (1a') and Ph-C≡C-(1,m)C6H4-C≡C-Au(PMe3) (m=4, 2a'; m=3, 3a') in place of the real system. Firstly, electronic structure methods based on DFT and TD-DFT are utilized to perform optimization calculations for the ground- and lowest-lying excited states, respectively. Next, basic photophysical properties including absorption and emission spectra are investigated by TD-DFT under the optimized geometries. Besides, on the basis of the electronic spectra herein, we succeed in searching for surface intersections as the minima on the seam of singlet-triplet surface crossings (SCs) at the CASSCF level of theory. By integration of the results available, the process of delayed fluorescence of triplet-triplet annihilation (TTA) and phosphorescence was displayed in detail with SCs playing the lead in monitoring the ISC.
authors.affiliation: Institute of Environmental and Analytical Sciences, College of Chemistry and Chemical Engineering, Henan University, Kaifeng 475004, PR China.
authors.forename: Li
authors.initials: L
authors.lastname: Wang
authors.affiliation: Institute of Environmental and Analytical Sciences, College of Chemistry and Chemical Engineering, Henan University, Kaifeng 475004, PR China.
authors.forename: Yuanyuan
authors.initials: Y
authors.lastname: Li
authors.affiliation: Institute of Environmental and Analytical Sciences, College of Chemistry and Chemical Engineering, Henan University, Kaifeng 475004, PR China.
authors.forename: Yanxin
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Wuhan Center for Magnetic Resonance, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Science, Wuhan 430071, PR China.
authors.forename: Hongqing
authors.initials: H
authors.lastname: He
authors.affiliation: Institute of Environmental and Analytical Sciences, College of Chemistry and Chemical Engineering, Henan University, Kaifeng 475004, PR China. Electronic address: zhangjinglai@henu.edu.cn.
authors.forename: Jinglai
authors.initials: J
authors.lastname: Zhang
mesh_terms: D065966:Absorption, Physicochemical; D000480:Alkynes / Q000737:chemistry*; D004583:Electrons; D004987:Ethers / Q000737:chemistry*; D006046:Gold / Q000737:chemistry*; D008958:Models, Molecular; D008968:Molecular Conformation; D011789:Quantum Theory; D012996:Solutions; D013050:Spectrometry, Fluorescence; D013499:Surface Properties
chemical_list: D000480:Alkynes; D004987:Ethers; D012996:Solutions; C436384:phenyleneethynylene; D006046:Gold
keywords: CASSCF; Delayed fluorescence; Dual emission; Gold(I) complexes; ISC; TD-DFT