title: Two bisthienylethene-Ir(III) complexes showing acid/base-induced structural transformation and on-off luminescence switching in solution.
abstract: Complexes [Ir(dfppy)2(pbdtiH)](PF6)·2CHCl3 (1-H) and [Ir(dfppy)2(pbdti)] (1) were synthesized by the reaction of bisthienylethene pbdtiH and an [Ir(dfppy)2Cl]2 dimer under neutral and basic conditions, respectively. Thus, the {Ir(dfppy)2}(+) unit is coordinated by pbdtiH in 1-H, and by pbdti(-) in 1, which are confirmed by their crystal structures. The structures of 1-H and 1 could be interconverted in solution, upon alternately adding NEt3 and TFA, thus resulting in reversible luminescence switching between the on-state of 1-H and the off-state of 1 at room temperature. In addition, both 1-H and 1 show solid-state luminescence, with a broad emission at 534 nm and 525 nm, respectively. The free pbdtiH ligand shows photochromic behavior in CH2Cl2 solution. However, no photochromism has been observed in 1-H and 1, indicating that the coordination of the pbdtiH/pbdti(-) ligand to the {Ir(dfppy)2}(+) unit could suppress their photochromic behaviors.
authors.affiliation: State Key Laboratory of Coordination Chemistry, Coordination Chemistry Institute, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, P. R. China. dkcao@nju.edu.cn.
authors.forename: Deng-Ke
authors.initials: DK
authors.lastname: Cao
authors.forename: Jiong-Sheng
authors.initials: JS
authors.lastname: Hu
authors.forename: Min-Qiang
authors.initials: MQ
authors.lastname: Li
authors.forename: Dan-Ping
authors.initials: DP
authors.lastname: Gong
authors.forename: Xiao-Xiong
authors.initials: XX
authors.lastname: Li
authors.forename: Michael D
authors.initials: MD
authors.lastname: Ward