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A novel conjugated molecule, L, based on 2,4,5-triphenylimidazole and 6-phenyl-2,2′-bipyridine (HCNN) was synthesized in two steps. The molecule can recognize Fe3+ in aqueous solution (THF/H2O, 1/1, v/v) by the appearance of new emission bands at 416 and 442 nm, which can be attributed to the emission of the newly formed L-Fe3+ complex. The binding constant of the complex was calculated to be (6.6±0.39)×103 M−1, and its formation was also confirmed by the appearance of isosbestic points at 312 and 381 nm in the UV-visible spectral titration experiment. While other transition and rare-earth metal ions, such as Mn2+, Fe2+, Co2+, Ni2+, Zn2+, Cd2+, Hg2+, Pb2+, Eu3+ and Nd3+, can only cause some decrease of L's fluorescence, alkali and alkaline earth metal ions, such as Li+, Na+, K+, Mg2+ and Ca2+, almost have no effect on L's fluorescence. The fluorescence of L can be recovered by the addition of EDTA to the L-Fe3+ system just due to EDTA's stronger chelating ability than that of L.  相似文献
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采用蒙特卡罗MMFF94分子力学力场方法搜索一类新发现的生物活性分子Alboatisin A~C的稳定构象,用梯度校正的B3LYP方法,计算其稳定构象的旋光度、振动圆二色谱(VCD)、电子圆二色谱(ECD)等光学活性,并从微观的角度对VCD谱和ECD谱中强或弱的正或负康登效应进行归属.从分子结构、电子结构和分子振动分析了分子手性的微观起源.结果表明,计算与实验的旋光度值相吻合,OH的取代位置与数目可调控旋光度发生在手性骨架上的振动或电子跃迁转移是手性光谱产生的重要原因.Alboatisin的圆二色谱是手性骨架变形振动的光谱响应,是不对称电子跃迁的光谱响应结果.  相似文献
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