title: Experimental and theoretical study on the sensing mechanism of a fluorescence probe for hypochloric acid: a Se···N nonbonding interaction modulated twisting process.
abstract: In this article, the sensing mechanism of a fluorescence probe for hypochloric acid, NI-Se, has been investigated using experimental and theoretical methods. Based on the results of the steady-state and time-resolved emission spectra of NI-Se and its oxidized form NI-SeO, we suggested that there was twist internal charge transfer (TICT) state with faint fluorescence in NI-Se. Subsequently, the ground and excited state minimum geometries of NI-Se and NI-SeO were optimized with DFT/TD-DFT methods. The results demonstrated there was a twisting process in the excited state of NI-Se and that this twist process was induced by the nonbonding interaction between the Se and N atoms. In addition, the calculated spectra and molecular orbitals confirmed the charge transfer character of the TICT state in NI-Se. To further investigate the driving force behind the twist in NI-Se, we synthesized NI-O, which has no Se···N nonbonding interaction, as a control sample. Herein, we also present the characterization, fluorescence properties and the optimized geometries of NI-O. Moreover, the results showed that Se···N nonbonding interaction plays a significant role in the twisting process of NI-Se.
authors.affiliation: State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics (DICP), Chinese Academy of Sciences (CAS), 457 Zhongshan Road, Dalian 116023, P. R. China. klhan@dicp.ac.cn.
authors.forename: Zhangrong
authors.initials: Z
authors.lastname: Lou
authors.forename: Songqiu
authors.initials: S
authors.lastname: Yang
authors.forename: Peng
authors.initials: P
authors.lastname: Li
authors.forename: Panwang
authors.initials: P
authors.lastname: Zhou
authors.forename: Keli
authors.initials: K
authors.lastname: Han
mesh_terms: D005456:Fluorescent Dyes / Q000737:chemistry*; D006997:Hypochlorous Acid / Q000737:chemistry*; D008958:Models, Molecular; D008968:Molecular Conformation; D009584:Nitrogen / Q000737:chemistry; D011789:Quantum Theory; D012643:Selenium / Q000737:chemistry; D012997:Solvents / Q000737:chemistry
chemical_list: D005456:Fluorescent Dyes; D012997:Solvents; D006997:Hypochlorous Acid; D012643:Selenium; D009584:Nitrogen