【作者】 郭志前；

【导师】 朱为宏；

【作者基本信息】 华东理工大学 ， 应用化学， 2010， 博士

【摘要】 化学传感器是超分子化学领域最活跃的研究领域之一,特别是化学传感器在生物方面的应用日益受到研究者的重视。自de Silva报道了第一个分子型AND逻辑门以来,分子逻辑门的研究取得了巨大的进展。传统的半导体硅材料通过电压变化实现逻辑运算,超分子化学则通过客体与主体的相互作用过程及对应的光谱信号变化,与逻辑计算过程的输入及输出一一对应。相对于传统半导体,在分子水平上构建逻辑操作最大的优势在于尺度小、可重构性好。故基于化学传感器构建分子逻辑门有着非常巨大的应用前景。分子荧光的优势在于灵敏度高、响应快、可在单分子水平上远距离监测及易于实现人与分子之间的联系等。本论文主要设计合成了以吡喃腈和菁染料为受体的系列衍生物,在分子结构中引入了不同的受体基团以及对吡喃腈母体的结构进行了修饰。根据典型的D-π-A体系中的受体基团对不同客体的识别作用,调控分子体系内的电荷转移(ICT)过程,利用在光谱上表现出不同的响应信号,成功地构建了具有序列响应、逻辑存储功能的分子键盘和具有比较功能的半减法器等组合逻辑门及荧光传感器。本论文的主要研究内容概括如下：第一章重点介绍了化学传感器的基本原理,以及对分子逻辑门的重要进展进行了综述,并提出本论文的研究内容。第二章设计、合成了以吡喃腈为受体的含有哌嗪单元的两个化合物DCMP和DCPP。研究发现,只有DCPP对Hg2+表现为选择性的荧光增强,而对Cu2+表现出强烈的荧光淬灭效应,并对其它测试金属离子表现出很好的选择性。进一步研究发现,化合物DCPP与Cu2+和Hg2+的配合常数为同一数量级,导致DCPP与一定当量的Hg2+和Cu2+配位时存在动力学竞争,表现为加入离子次序不同得到的荧光信号输出不同。利用DCPP与Hg2+和Cu2+在配位过程中的动力学差异,成功地构建了一个具有序列响应、逻辑存储功能的分子键盘。第三章设计、合成了含有二甲基吡啶(DPA)单元和pH响应的“V”型双边化吡喃腈衍生物DADPP,详细研究了DADPP作为Zn2+探针的性能。DADPP在不同酸碱条件下与Zn2+作用产生了DADPP、DADPP-、DADPP--Zn2+及DADPP-Zn2+四种不同状态,并伴随产生不同的光谱变化。利用DADPP四种不同状态之间的转换,实现在光谱上的变化作为响应输出,成功构建了含有比较功能的半减法器。第四章基于吡喃腈荧光单元,通过自由基聚合合成了温度敏感性聚合物poly(NIPMAM-co-MDCPDP).研究发现,该聚合物对Cu2+的荧光选择性荧光淬灭与pH密切相关,只有在pH<7时才表现出强烈的荧光淬灭作用,而pH=10时,却对Cu2+没有响应。利用聚合物在不同的pH值下其吸收和荧光光谱表现出截然不同的温度响应,选择以pH值作为一个信号输入,温度(Temp)和Cu2+两者之一作为另外一个输入,成功的模拟了两个INHIBIT逻辑门；以pH值、温度(Temp)及Cu2+为三个输入成功地实现了两个NOR逻辑门并行的组合逻辑门。第五章设计、合成了亲水型的荧光聚合物poly(HEMA-co-MDCPDP).该聚合物对Cu2+表现出快速的选择性荧光淬灭效应,且配位后的薄膜在EDTA的水溶液中能重复使用。进一步合成了聚合物的金属配合物poly(HEMA-co-MDCPDP)-Cu2+,研究其对阴离子识别作用发现,其对焦磷酸根(PPi)表现为选择性荧光增强,并对PPi、AMP、ADP和ATP表现出很高的选择性,并且poly(HEMA-co-MDCPDP)-Cu2+的薄膜与PPi作用在5 min左右达平衡。成功地发展了基于"ensemble"法PPi阴离子的荧光探针,其具有近红外、荧光增强、高选择性等优点,有望对生物过程中在线监测PPi的浓度变化具有潜在的应用价值,极大地解决了荧光传感膜的成膜性、膜的通透性、亲水性和溶涨等一系列制约微型化反应器实际应用的问题。第六章基于汞促进硫脲成胍的反应,设计合成了三个菁染料的近红外比值型荧光探针IR-877、IR-897及IR-925,并研究三个不同的异氰硫脲基团的取代基效应。IR-877和IR-897与Hg2+作用时有明显的吸收光谱偏移,分别产生176和162 nm的波长红移,在荧光光谱上780 nm处荧光淬灭而在830 nm处荧光增强,而IR-925在合理的有效检测时间内光谱上几乎没有变化。通过激发光谱模式的双激发、等吸收光点激发的双发射等方法,IR-897和IR-877可作为近红外的比色法和荧光比率型探针检测无机Hg2+和有机的甲基汞离子,并具有高选择性和高灵敏性的等优点,检测最低限可达到纳摩尔(nmol)级,成功地开发快速定性检测Hg2+和MeHg+试纸,极大地避免微环境测量时的荧光单元的浓度、光程以及激发光强度的漂移会引起错误的读出。另外,通过细胞成像研究发现该类探针具有很好的膜渗透性,可作为近红外、生物检测的比率型荧光探针,提供了一种新的设计思路。第七章设计合成了基于喹啉为受体的四个化合物DDCM、DDCP、DECM及DECP,研究了其分子聚集荧光增强(AIE)效应,并采用单晶结构进一步研究了DDCM的堆积方式。对长碳链的DDCM、DDCP作为阴离子表面活性的探针进行初步检测。另外,合成一系列基于苯并吡喃腈和多吡啶的化合物,总结了一些尝试性的工作。更多还原

【Abstract】 The development of highly sensitive and selective chemosensors has become an active area in supramolecular chemistry, especially in the biology and microenviroment. The remarkable progress in the development of molecular logic gates has brought chemists closer to the realization of molecular-scale calculator since the first report of molecular AND logic gate based on chemosensors by de Silva et al. Compared with the modern semiconductor IT industry, molecular logic gates can be viewed as computational devices that process physical or chemical "inputs" to generate "outputs" based on a set of logical operators. The molecular logic systems can also make themselves to convenient reconfiguring, especially for application in the life sciences. The "bottom-up" method exhibits a distinct advantage over conventional semiconductor counterparts. As a consequence, molecular logic function can be designed in chemical and intracellular sensing, small object recognition and intelligent diagnostics.Molecular fluorescence has many remarkable advantages, such as high sensitivity down to the single molecule, easy detection and wide dynamic ranges. With further understanding molecular recognition and increasing skills in molecular design, several Donor-π-Acceptor (D-π-A) chemosensors based on dicyanomethylene-4H-pyran and cyanine derivatives were synthesized for the detection of cations and anions, and successfully constructed as memory keypad and half-substractor with comparator function. The main contents and results are outlined as follows:In Chapter 1, the major sensing principles of optical chemosensors are introduced, and the progress of molecular switches and logic gates performing distinct signalling output is reviewed.In Chapter 2, a novel fluorescent probe DCPP possessing both DCMP and 2,6-bis(amiomethyl)pyridine moieties was designed for detecting Hg2+and Cu2+. The characteristic fluorescence of Hg+-selective OFF-ON and Cu+-selective ON-OFF can be monitored, and controlled reversibly by the sequence and ratio of Hg2+and Cu2+inputs, which has been successfully constructed as a keyboard capable of crossword puzzles and logic memory at the molecular level based on the above logic operation. It provides a characteristic signaling pattern which can perform distinct algebraic operations solely in the fluorescence mode with the same excitation wavelength and be detectable in fluorescence for straightforward "reading" of the arithmetic results. The concept of such crossword puzzle based on fluorophores can be expected to greatly develop the combinatorial logic operations in sequential logic circuits with memory function.In Chapter 3, a V-shaped molecule of DADPP was designed, containing two receptors such as an aromatic unit possessing bis(2-pyridyl-methyl)amine (DPA) moiety and a phenolic moiety, via double bonds as bridges to incorporate a dicyanomethylene-4H-pyran unit as chromophore. A half-subtractor with a combination of comparator has been constructed based on intramolecular charge transfer (ICT) process resulting from hosting two different guests with the binding of Zn2+and the deprotonation of phenolic hydroxyl group in a unimolecular system. The corresponding spectral shifts in absorption and a variation in fluorescence intensity were well elucidated. An XOR (exclusive OR) logic gate generates the difference digit of half-subtractor reading at 445 run, and two INHIBIT logic gates are achieved for the borrow digit of half-subtractor when the output signals are monitored at 400 and 525 nm, respectively. Taken together, the comparison and subtraction operations are practically performed in parallel without mutual interference due to the same inputs and different outputs within the same molecule system.In Chapter 4, a novel thermometer fluorescent sensor poly(NIPMAM-co-DCPDP) consisting of N-isopropyl methacrylamide as a thermoresponsive unit and dicyanomethylene-4H-pyran derivative as a dipolar-sensitive fluorophore unit was designed. Poly(NIPMAM-co-DCPDP) performs fluorescence quenching merely by coordination with Cu2+ions or increasing temperature in neutral or acid aqueous solution.The ON-OFF fluorescence response of poly(NIPMAM-co-DCPDP) is driven by a temperature-induced phase transition from coil to globule and the capture of Cu2+ions resulting in a decrease of the ICT efficiency in neutral solution. The combinational serial NOR logic operation as well as two INHIBIT logic gates was constructed with three inputs:various pH, temperature change, and Cu2+ions. The proposed combinational logic circuits play a key role in mimicking comprehensive arithmetic operations at the nano-scale level.In Chapter 5, a new strategy of incorporating ion-sensitive fluorescent unit to form hydrophilic copolymer poly(HEMA-co-MCPDP) has been developed as film sensor for Cu2+ and PPi.2-hydroxyethyl methacrylate (HEMA) as a neutral hydrophilic chain segment is chosen as monomer for its high hydrophilicity to improve ion permeability into the polymer matrix. Using the ensemble method, the related metal complex, poly(HEMA-co-MCPDP)-Cu2+, shows turn-on fluorescence and high sensitivity for PPi both in solution and thin film over other anions such as adenosine triphosphate (ATP) and phosphate (Pi). The low-cost hydyophilic copolymer film of poly(HEMA-co-MCPDP)-Cu2+ exhibits high sensitivity and rapid response to PPi with turn-on orange-red fluorescence, showing an ideal hydrophilic film strategy for low-cost anion chemosensors or chips to the on-line monitor and high-throughput bio-processing in continuous system.In Chapter 6, three tricarbocyanine derivative dyes (IR-897, IR-877, and IR-925) with different isothiocyanate substituents as dosimeter units via the specific Hg2+-induced desulfurization have been synthesized for developing near-infrared (NIR) colorimetric and ratiometric chemodosimeters to mercury ion. The distinct response is dependent upon the electron-donating effect of isothiocyanate substituents, that is, the stronger in the electron-donating capability of isothiocyanate substituents, the faster in the Hg2+-promoted cyclization. IR-877 and IR-897 with Hg2+exhibit large red shifts in absorption (176 and 162 nm, respectively), fully meeting "naked-eye" colorimetric changes and successfully developed as Hg2+and MeHg+indicator paper. Moreover, measuring either a single emission with two excitation sources (excitation spectra mode) or dual emission with an isosbestic absorption point as single excitation source, these chemodosimeters can be successfully constructed as the first NIR ratiometric Hg2+sensors, allowing for fast and accurate measurements with eliminating the influence of dye concentration and microenvironmental fluctuations in pH, refractive index and photobleaching.In chapter 7, a series of novel Aggregation-induced Emission (AIE) luminescent materias (DECM, DDCM, DECP and DDCP) were designed and synthesized. The structure is a typical D-π-A structure containing quinoline unit as electron-receptors, N,N-dimethylaniline and triphenylamine unit as electron-donor. Their AIE effects were fully studied with absorption and fluorescence spectra. Moreover, the potential application was done for detection of anionic surfactants.In addition, some other synthetic work was introduced. A new series of DCM derivatives based on dicyanomethylene-4H-chromene with different receptors was designed.更多还原