title: Design, synthesis and properties of near-infrared molecular switches containing a fluorene ring.
abstract: Three molecular switches containing a fluorene ring were designed and synthesized. The introduction of the amino group substituted fluorene ring resulted in the target molecular switches having some optical properties in the near-infrared region. It was demonstrated that the N-substituents on the fluorene rings and the switch units both had great influence on the molecular switch optical properties including the absorption maximum, absorption intensity and fluorescence quantum yield. The open-ring forms and showed obvious solvatochromic behaviour. The closed-ring forms and showed obvious hydrochromic behaviour in MeCN/water binary solvent systems and acidichromic behaviour in MeCN solution with high reversibility. Especially, the distinct off-on fluorescence signal in the near-infrared region using the stimuli of acid means that the designed compounds have great potential application value in the field of biological sensing.
authors.affiliation: State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun 130012, People's Republic of China. seanzhang@jlu.edu.cn and State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, College of Chemistry, Jilin University, Changchun 130012, People's Republic of China.
authors.forename: Peng
authors.initials: P
authors.lastname: Chen
authors.affiliation: State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun 130012, People's Republic of China. seanzhang@jlu.edu.cn.
authors.forename: Hai-Ming
authors.initials: HM
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun 130012, People's Republic of China. seanzhang@jlu.edu.cn.
authors.forename: Guo-Jie
authors.initials: GJ
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun 130012, People's Republic of China. seanzhang@jlu.edu.cn.
authors.forename: Sean Xiao-An
authors.initials: SX
authors.lastname: Zhang