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A series of novel near-infrared (NIR) xanthene-chalcone fluorophores were constructed through a modular synthesis with the electron-donating xanthene moiety and the electron-withdrawing chalcone moiety. These fluorophores are convenient for fluorescence imaging in living cells, benefiting from their NIR emissions (650–710 nm), large Stokes shifts (>100 nm), moderate quantum yields and low cytotoxicity. The substituted hydroxyl group of the xanthene-chalcone fluorophore HCA-E facilitates the development of multifunctional fluorescent probes. As an example, a highly sensitive and selective probe N-HCA-E for glutathione (GSH) detection was developed based on the fluorophore HCA-E. A 4-nitrobenzenesulfonyl (4-Ns) group was introduced to cage the hydroxyl group of HCA-E, which was used as a selective recognition site for the thiol of GSH and an effective fluorescence quencher. Probe N-HCA-E revealed NIR "turn-on" fluorescence (709 nm) for endogenous and exogenous GSH detection in lysosomes with a large Stokes shift (129 nm) and high anti-interference ability. [ABSTRACT FROM AUTHOR]

Hydrazine has been identified as an environmental contaminant and a probable human carcinogen for its high toxicity. Thus, the development of detection methods for mapping hydrazine in solution and biosystems, particularly in vivo , is of great significance. Here, through firstly exploited 2-thiophenecarbonyl moiety as a recognition unit for hydrazine, a novel near-infrared (NIR) fluorescent probe CyOS is obtained based on hemicyanine. The probe shows high selectivity towards hydrazine over various amino acids and common ions with a significant fluorescence enhancement at 701 nm in the presence of hydrazine. Further, it has a sufficiently low detection limit (0.78 ppb). And most importantly, due to its good cell membrane permeability and low cytotoxicity, CyOS has been applied to monitor and image hydrazine in living cells, tissues and mice. To the best of our knowledge, it is the first time to visualize hydrazine in deep living tissues (∼90 μm). [ABSTRACT FROM AUTHOR]

Two functionalized rhodamine based probes have been rational designed and synthesized. The probes have sufficiently high selectivity and sensitivity for the detection of Fe 3+ ion both by fluorescence and ultraviolet spectroscopy with strong ability of anti-interference performance. The detection process has been shown to be reversible and involves the fluoran ring-opening upon complexation with Fe 3+ . The obvious fluorescence image obtained from confocal laser scanning microscopy of the detection of Fe 3+ in living L929 cells demonstrate that the probes could contribute to significant breakthroughs in understanding the critically important functions of Fe 3+ in related cells and biological organs. [ABSTRACT FROM AUTHOR]

A novel rhodamine based 2-guanidinobenzimidazole functionalized probe RhoG was rationally designed and synthesized for the detection of tetravalent tin in environmental, geological, and biological samples with excellent selectivity, sensitivity, photostability and anti-interference performance. The mechanism investigation confirmed that guanidinobenzimidazole provided binding sites for Sn 4+ and facilitate the formation of the complex. Successfully fluorescent imaging experiments in living L929 cells and MG-63 cells by confocal laser scanning microscopy presented a promising candidate for tracking tetravalent tin in biological organisms and processes thus contribute to significant breakthroughs in understanding the critically important functions of tetravalent tin. [ABSTRACT FROM AUTHOR]

Three congeneric fluorescent sensors that utilize Rhodamine B were developed for the detection of mercury (II) ions. This series of sensors are functionalized by various differently substituted cinnamyl aldehyde, with C N Schiff base and C S structural motif as their core segment. The performance of these sensors adjusted by steric hindrance were investigated by absorption and fluorescence spectrum, and illuminated, summarized and confirmed using DFT calculations by frontier orbital theory and Fukui- function. In addition, living cell and living mice imaging demonstrated that all the sensors could serve as a potential fluorescent agent for quantitative mercury (II) ion imaging in living organism. The obvious morphology change reveal that the coordination of HgCl 2 upon these sensors may have a great influence on the material performance to a certain extent. This approach provides a significant strategy for studying structure-property relationships and guiding the synthesis of sensors with various optical properties. [ABSTRACT FROM AUTHOR]