【作者】 邹文生；

【导师】 晋卫军；

【作者基本信息】 山西大学 ， 分析化学， 2008， 硕士

【摘要】 第一章卤键是发生在卤素原子（路易斯酸）与中型或阴离子路易斯碱之间的一种非共价弱相互作用力,本章主要对卤键发展的历史与现状及主要特征进行了综述,并突出其与氢键的相似性,介绍了基于卤键晶体工程发展中的一些启示性原理,焦点集中于卤碳的卤键超分子体系,显示了卤键在合成化学、材料科学、化学传感与分子识别及生物有机化学领域的应用潜力。第二章在HF/6-31（d）水平上对气相中的CBr4/甲醇、乙醇、乙醚、四氢呋喃、二氧六环的单体和配合物的构型进行优化得到了配合物的键长、键角、相互作用能等参数,键长位于范得华半径之内表明Br…O间的卤键弱相互作用力的存在。对四溴化碳溶于甲醇、乙醇、丙酮、四氢呋喃等含氧孤电子对有机溶剂的光电性能的研究表明:当浓度超过7.8×10^-3M～1.6×10^-2M的临界浓度范围时,高浓度依赖性的卤键特殊溶剂效应与最高浓度的一般溶剂效应共存,相反地,当浓度低于此临界浓度范围时,溶液中仅存在一般溶剂效应。卤键供/受体间的电荷转移（CT）相互作用如同氢键一样导致了光谱的红移,其中,电荷转移配合物的紫外-可见吸收光谱在丙酮溶剂中易于辨认,而其它五个溶剂的光谱则必须通过特殊溶剂效应曲线减去最高浓度的一般溶剂效应曲线才能得到。适合二组分体系的Benesi-Hildebrand方程证实了四溴化碳与各种溶剂间形成丁1:1的配合物。四溴化碳溶解在甲醇、乙醇、丙酮、四氢呋喃中的氧化电位与相应的吸收能量的线性关系建立了CBr4/溶剂的高浓度依赖性的电荷转移性能间的关系。试验过程中发现:环境光辐射使四溴化碳脱溴从而导致了350～390nm范围内的光谱拖尾。第三章得到了DPY/5-Isal和Py/DIF₄B分子间自组装晶体,单晶衍射结果表明:前者以5-碘水杨酸分子间的C-I...O（羰基）卤键作为两侧“梯柱”,两侧“梯柱”羧酸上的羟基与4,4-二吡啶以氢键结合形成“梯梁”的“梯”状晶体;后者是由两个Py分子中包含两个碘反向的DIF₄B分子的“夹心”柱状无限链结构,Py及DIF₄B间以π-π堆积为驱动力,柱状链间则通过I…I作用连接。研究表明卤键与氢键及π-π堆积等弱作用间的协同作用对人类生命起源的认识、药物设计及生物体内分子间识别具有重大的意义。第四章本文报道了1,2-2（4-吡啶）乙烯（BPE）随pH变化的光谱特性。当pH值从7.20减少到-1.0时,紫外-可见吸收以及荧光光谱在四个不同的连续的pH区间8.45～7.20,7.20～5.62,5.62～2.60,2.60～-1.0呈现相同的变化趋势。即不变,减弱,增强,再减弱。其中,在7.20～5.62的范围内,紫外-可见吸收波长由298nm红移到313nm,荧光发射由418nm蓝移到359nm;当pH2.60低到-1.0左右,阳离子-π作用降低了π电子云密度使荧光强度减弱直至猝灭。通过拟合得到两级解离常数pKa₁=4.30±0.01和pKa₂=5.65±0.04,光谱变化显示:该化合物按pH值由高到低显示了“关-开-关”的荧光发射性能,可应用于荧光分子开关,同时又是一个较好的pH探针。α-,β-环糊精的存在对光谱几乎无影响。更多还原

【Abstract】 Chapter 1 Halogen bonding is the noncovalent interaction between halogen atoms（Lewis acids） and neutral or anionic Lewis bases.History,current situation and main features of the interaction were given,and the close similarity with the hydrogen bonding became apparent.Some heuristic principles are presented to develop a rational crystal engineering based on halogen bonding.The focus was on halogen-bonded supramolecular architect- tures given by halocarbons.The potential of the interaction was shown by useful applications in the field of synthetic chemistry,material science,chemical sensing and molecular recognition,bioorganic chemistry.Chapter 2 The data about geometries and interaction energies for the carbon tetrabromide complexes with methanol,ethanol,dioxane,dietyl ether, tetrahydrofuran using ab initio methods were obtained.C-Br…O distances are within the van der Waals radius sum,which revealed the existence of the weak halogen bonding interaction between Bromine and Oxygen atoms.The photoelectrical characters of carbon tetrabromide（CBr₄） dissolved in methanol,ethanol,acetone,dioxane,dietyl ether,tetrahydrofuran were investigated.High concentration-dependent halogen bonding（XB） specific solvent effect co-existed with the highest concentration general solvent effect when concentration of CBr₄ was over 7.8×10^-3M～1.6×10^-2M critical concentration range,in contrary,below this concentration range only did general solvent effect occur.Charge-transfer（CT） interaction between halogen bonding donor-acceptor resulted in spectral red-shift as hydrogen bonding （HB）.Among these,UV-Vis spectrum of specific solvent effect was resolved easily in acetone,as for other five solvents,only could by spectral digital subtractions of the critical concentration absorption of CBr₄ from the spectra of solutions containing both reagents obtain the distinct spectra of specific solvent effect due to the spectra overlaping between the highest concentration general solvent effect and specific one.1:1 complexes formed were testified by modified Benesi - Hildebrand equation.The linear correlation of anodic potentials with the spectral energies of four organic solvents complexes established the high concentration-dependent charge-transfer character of the CBr₄/solvent associations.Ambient light made CBr₄ disassociate bromine which lead to spectral tail in the range of 350～390nm.Chapter 3 In this chapter the intermolecular crystals self-aggregated by DPY/5-Isal and Py /DIF₄B were obtained,respectively.The results from single crystal diffraction indicated:The former was ladder-like crystal with the feature of both bilateral "ladder columns" constructed by the C-I…O （carbonyl） halogen-bonding from 5-Isal molecules and "ladder girder" did by hydroxide from carboxylic group and nitrogen from 4,4-Bipyridyl.The latter was "sandwiched column-like" infinite chain containing two DIF₄B molecules with reverse iodine between two Py molecules,π-πstacking drove the self-aggregation of Py and DIF₄B molecules,but the two neighboring columns were connected by I…I interaction.Synergetically interaction by halogen-bonding with hydrogen-bonding,π-πstacking and other weak interactions had great meaning for the understanding for life initiation, medical design and intermolecular recognition in biological bodies.Chapter 4 With decrease ofpH from 7.20 to-1.0,the UV-Vis absorption and fluorescent spectra of the 1,2-bis（4-pyridyl） ethylene（BPE） took on same changing trends at four different successive pH stages:8.45～7.20,7.20～5.62, 5.62～2.60,2.60～-1.0,namely corresponding to no change,decrease,increase, decrease again.Among these,at the range of 7.20～5.62,the wavelength of fluorescence blueshifted from 418nm to 359nm,but that of UV-Vis,in contrast,redshifted from 285nm to 298nm.Fluorescence had a drop even to quench upon pH from 2.60 to -1.0 due to its cation-πinteraction to reduceπelectron cloud density of BPE Two dissociation constants,pKa₁ 4.30±0.01 and pKa2 5.65±0.04,were obtained based on fluorescence data.The changes of spectra indicated that BPE had "off-on-off’ fluorescence emission behavior.The spectra of BPE were nearly independent on the presence ofαandβ-cyclodextrins.更多还原