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Abstract: Two novel 6-phenyl-2,2′-bipyridine derivatives based on aza-crown ether groups were synthesized and characterized, one of which was characterized by single crystal X-ray diffraction determination. Their linear photophysical properties were systematically investigated in various solvents. The nonlinear photophysical properties were investigated by two-photon induced fluorescence method. Both dyes exhibited large two-photon absorption cross-section (δ 2PA ). The cytotoxicity of the dyes was evaluated in HepG2 cell line to assess the potential application for biomedical imaging. Two-photon fluorescence microscopy (TPFM) imaging of two dyes in HepG2 cell line was demonstrated, which indicated that introduction of the hydrophilic aza-crown ether facilitates biological compatibility of dyes. [Copyright &y& Elsevier]

Abstract: The interaction of daunorubicin (DNR) with herring sperm DNA in cyclomaltooctaose (γ-cyclodextrin, abbrev. γ-CD) supramolecular system was studied by UV–vis absorption spectroscopy, fluorescence spectroscopy and viscosity method. On the condition of physiological pH, the results indicate that DNR prefers to form the 1:1 inclusion complex with γ-CD. These results are further supported by infrared spectrometry (IR), and X-ray diffraction (XRD). An inclusion constant (K) for the formation of γ-CD–DNR inclusion complex has been evaluated to be 9412.39Lmol−1 from the absorbance changes. It is observed that the interaction mode between γ-CD–DNR and DNA are a mixed binding, which contains partial intercalation and groove binding. The binding ratio of γ-CD–DNR with DNA is n γ-CD–DNR:n DNA =10:1, binding constant is K Θ 298.15K =2.44×105 Lmol−1, enthalpy and entropy work as driven force in this action. [Copyright &y& Elsevier]