title: Design and syntheses of electron-transfer photochromic metal-organic complexes using nonphotochromic ligands: a model compound and the roles of its ligands.
abstract: The model compound [Zn(HCOO)2(4,4'-bipy)] (1; 4,4'-bipy = 4,4'-bipyridine) is selected in this work to demonstrate the effectiveness of our previously proposed design strategy for electron-transfer photochromic metal-organic complexes. The electron-transfer photochromic behavior of 1 has been discovered for the first time. Experimental and theoretical data illustrate that the photochromism of 1 can be attributed to the electron transfer from formato to 4,4'-bipy and the formation of a radical photoproduct. The electron transfer prefers to occur between formato and 4,4'-bipy, which are combined directly by the Zn(II) atoms. A high-contrast (up to 8.3 times) photoluminescence switch occurs during the photochromic process. The similarity of photochromic behaviors among 1 and its analogues as well as viologen compounds has also been found. Photochromic studies of this model compound indicate that new electron-transfer photochromic metal-organic complexes can be largely designed and synthesized by the rational assembly of nonphotochromic electron-donating and electron-accepting ligands.
authors.affiliation: State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences , Fuzhou, Fujian 350002, People's Republic of China.
authors.forename: Cui-Juan
authors.initials: CJ
authors.lastname: Zhang
authors.forename: Zi-Wei
authors.initials: ZW
authors.lastname: Chen
authors.forename: Rong-Guang
authors.initials: RG
authors.lastname: Lin
authors.forename: Ming-Jian
authors.initials: MJ
authors.lastname: Zhang
authors.forename: Pei-Xin
authors.initials: PX
authors.lastname: Li
authors.forename: Ming-Sheng
authors.initials: MS
authors.lastname: Wang
authors.forename: Guo-Cong
authors.initials: GC
authors.lastname: Guo