【作者】 张晓琳；

【导师】 肖义； 钱旭红；

【作者基本信息】 大连理工大学 ， 应用化学， 2009， 博士

【摘要】 荧光共振能量转移(FRET)在荧光染料分子的设计中起着举足轻重的作用,已成为有机化学在各个领域应用的不可或缺的重要桥梁。在FRET体系中,最重要也是最核心的部分就是供体和受体的选择。本文基于氟硼吡咯荧光团优异的光化学和光物理性质,采用其衍生物做为供体和受体部分设计并合成了多种FRET体系,并通过实验测试初步评估了其应用价值。1.设计并合成了一系列基于FRET机理的多种氟硼吡咯衍生物光捕集天线系统。其中首次实现了三种不同吸收波长的氟硼吡咯衍生物组合分子----光捕集天线A11。该分子利用不同取代基的氟硼吡咯衍生物作为FRET的供体和受体,使其不仅具有氟硼吡咯荧光团的强吸收性质,而且由于多氟硼吡咯衍生物的组合弥补了单个氟硼吡咯本身吸收谱带狭窄的缺陷,使其吸收光谱可覆盖300～700 nm这一太阳能的强辐射范围。在这个系统中,从供体到受体的能量转移可高达99%。“Click”化学反应在合成中的引用大大提高了反应的产率,简化了合成的难度,使这一系列光捕集天线的进一步应用成为可能。这个研究表明氟硼吡咯衍生物作为太阳能光捕集天线具有很好的实用性。2.分别构建了氟硼吡咯和罗丹明6G以及氟硼吡咯和罗丹明B的两种FRET体系BRB和BR6G,通过罗丹明隐色体部分与汞离子的高效专一反应来实现对FRET由“关”到“开”状态的逆转。在正常生理条件上,BRB探针和BR6G探针对汞离子具有高度的选择性,竞争性以及高度灵敏性。识别汞离子后可使BRB探针以及BR6G探针的荧光最大发射波长分别红移46 nm和75 nm,确保了比率识别的灵敏度。与此同时,荧光颜色从绿色荧光分别了变成红色荧光和黄色荧光,便于肉眼直接观察。值得一提的是,BRB检测极限甚至可达ppb级,达到了环境保护局(EPA)对汞离子的检测要求。在细胞荧光成像实验中,探针BR6G和BRB都显示出了非常好的汞离子比率检测性能,真正做到了实用性。3.设计并合成了以萘酰亚胺和氟硼吡咯衍生物作为FRET供体和受体的pH荧光探针C6,其在pH于2.07-3.68范围的强酸环境下可实现对pH的窄响应范围比率检测,斯托克位移可达近200 nm。荧光量子效率在强酸性条件下可比在中性条件下提高23倍。随着能量受体氟硼吡咯衍生物部分的质子化,其在567 nm处的荧光发射显著增强,而与此同时,供体萘酰亚胺的荧光发射光谱由于与受体氟硼吡咯部分的吸收光谱交盖程度更大,其在515 nm处的荧光发射则有下降趋势。这是FRET机理应用于探针设计的新思路,即通过与被识别对象的作用改变供体的发射光谱和受体的吸收光谱重叠程度,进而改变荧光共振能量转移效率,最后导致荧光光谱的变化实现识别过程。更多还原

【Abstract】 Fluorescence resonance energy transfer （FRET） plays an important part in the design of fluorescent dyes and has become an essential bridge connecting organic chemistry and other fields. In the system based on FRET, the most importment part is the selectivity of donor and acceptor. In this paper, a few systems based on FRET were designed and synthesized, which adopted BODIPY fluorophore as donor or acceptor due to its excellent photophysical and photochemical properties.1. A series of light harvesting systems based on BODIPY derivatives were designed and synthesized. Among them, light harvesting system A11 first realized the combination of three kinds of BODIPY derivatives with different wavelengths. It has strong absorption covering 300-700 nm. Furthermore, the energy transfer efficiency from donor to acceptor can arrive to 99%. The introduction of "Click" chemistry simplied the difficulty of synthesis and made its application possible.2. Building two kinds of FRET systems BRB and BR6G with BODIPY as donor （Rhodamine 6G and Rhodamine B as acceptor respectively） and inspecting their application. BRB and BR6G can realize FRET from "off to "on" through an irreversible Hg²⁺-promoted oxadiazole forming reaction of leuco Rhodamine derivatives. In the normal physiological conditions, BRB and BR6G showed highly selectivity and sensitivity for mercury ions. After detecting mercury ions, maximum fluorescence-emission made blue shift about 46 nm and 75 nm respectively. Meanwhile, fluorescent color changed from green to red and yellow respectively, which was readily detectable visually. One thing worthy of note is that the detection limit of BRB is at the parts per billion level, which can satisfy the requirement of Environmental Protection Agency （EPA）. Fluorescent imaging experiments in animal cells show that BRB and BR6G can realize the fluorescent ratio detection of mercury ions.3. Fluorescent probe C6 for pH based on 1, 8-naphthalimide and BODIPY derivatives was designed and synthesized. It can realize pH detection in 2.07 - 3.68. Furthermore, stoke shift can arrive to 200 nm and fluorescence quantum efficiency can icrease 23 times as much. It indicated that fluorescent ratio detection of pH through change of overlapping spectra was possible.更多还原