【作者】 赵小菁；

【导师】 朱志昂；

【作者基本信息】 南开大学 ， 物理化学， 2004， 博士

【摘要】 卟啉化学是化学、物理、生命材料和信息等领域学科交叉的研究热点,在生物无机化学、配位化学和主客体化学等领域都具有重要意义,对它的研究一直是倍受关注的课题。且由于金属卟啉在生物化学中的重要地位,使其在仿生化学研究中具有非常特殊的重要意义。本论文研究了金属卟啉以及卟啉-Salen金属锌二聚物的分子识别,并应用理论化学工具,进行了深入的探讨和研究。本论文主要内容如下:1.合成了共六种新型的由氨基酸衍生物修饰的自由卟啉及其金属锌配合物,采用紫外可见光谱、核磁共振波谱、红外光谱以及圆二色光谱等手段对它们进行了表征;合成了共十二种未见报道的不同烷烃链长链接的卟啉-Salen二聚物及其金属锌双核化合物,同样进行了详细的表征。2.研究了手性Boc保护氨基酸修饰的锌卟啉对咪唑类客体的分子识别行为。用紫外-可见光谱滴定法测定了识别体系的缔合常数,研究了各种因素对主客体体系缔合能力的影响。实验结果表明,主客体结构以及温度等均对缔合能力有明显的影响;研究了该反应的热力学性质和焓熵补偿关系;首次用CD光谱对锌卟啉与咪唑客体的分子识别行为进行了研究,并与热力学结果相比较得到一致;首次采用模拟退火法和量化计算相结合的方法研究了识别体系的最低能量构象以及确定了本识别体系中主客体结合的方式应为客体从主体的单支链方面与其结合形成缔合物。3.研究了手性Boc保护氨基酸修饰的锌卟啉对氨基酸酯的手性分子识别行为。测定了识别过程中的缔合常数,研究了该体系的热力学性质和焓熵补偿关系,计算了各体系的对映异构体选择性,其中α,α,α,β-ZnT(o-BocAla)APP对LeuOMe的选择性为6.9,是本识别体系中的最高值;并发现低温有利于提高选择性,为手性分子识别的应用研究提供了实验材料和理论依据;研究了手性识别体系的核磁共振波谱,指出了识别体系主客体的结合方式为卟啉金属锌与客体分子上的氮原子结合形成了Zn-N配位键,并证明体系的核磁变化反映了主客体的结合能力;同样用CD光谱研究了手性识别体系的缔合过程,解释了主体分子和主客体体系CD光谱形成的机理;首次用模拟退火法和量化计算方法相结合对手性识别体系进行了理论研究,从理论上证明了主体对L-/D-氨基酸酯客体的不同结合能力,以期达到理论与实践相结合的最佳研究方式。4.研究了卟啉-Salen双核锌二聚物ZnPSC10与刚性双齿配体DABCO的分子识别行为。首次采用核磁滴定法对二聚物与DABCO的结合方式进行了详尽的研究,以单核锌卟啉ZnTPP与DABCO的配位反应作为对照体系,认为主客体缔合后形成了夹心式的稳定构象,其引起的环流效应极大地影响了主体和DABCO的质子化学位移;首次提出两种不同化合物形成的二聚物在热力学研究过程中的各参数的测定方法,即对组成二聚物两个不同部分分别进行求取;首次得出结论由于卟啉的配位能力强于Salen的配位能力,反映到所求取的热力学参数均为卟啉部分的大于Salen部分,并由所求得的热力学参数可以反映出缔合物的夹心式构象是稳定存在的;采用分子力学和量化计算相结合的方法理论上研究了体系的稳定构象,证明夹心式构象是该识别反应的稳定构象。5.研究了卟啉-Salen双核锌二聚物ZnPSC10与三种含氮客体吡啶、DABCO及吡嗪的分子识别行为。以单核主体ZnTPP与客体分子的分子识别研究作为对照体系,得出该体系的配位能力顺序为:吡啶>DABCO>吡嗪;由理论计算研究得出结论客体的HOMO能级越高,配位能力越强;首次根据分子力学优化和量化计算的结果判断出主客体结合的各种可能构象中存在的最稳定构象。更多还原

【Abstract】 Porphyrin chemistry has already been important in many intersectional investigations such as chemistry, physics, life material and informatics. Metalloporphyrins are of great significance in the field of bioinorganic chemistry, coordination chemistry and host-guest chemistry. Studies on metalloporphyrins have always been a main point. As an important role in biochemistry, metalloporphyrins have been used in biomimic studies of consequence. Molecular recognition of metalloporphyrins and porphyrin-salen dimers have been studied in this thesis, and theoretic chemistry has been performed to investigate. The main content is shown as follows:1. Six new free and zinc porphyrins modified by amino acid derivatives were synthesized and characterized by UV-vis, 1HNMR, IR, CD spectrum; Twelve new free and zinc porphyrin-salen dimers linked by different lenth alkyl chain were synthesized and characterized.2. The molecular recognition of imidazoles by modified zinc porphyrins was studied. The association constants of the system were measured by of UV-vis titration, and affect factors of association constants were discussed, which include the steric configuration of host, guest molecules and temperature; The thermodynamic properties and enthalpy-entropy compensation were considered; The CD spectrum was first time used to study the recognition of this system, according to the results of thermodynamic; The minimal energy conformations and binding mode of host-guest systems were obtained by simulated annealing and quantum chemistry.3. The chiral recognition of amino acid esters by modified zinc porphyrins was investigated. The association constants between hosts and guests were measured. The thermodynamic parameters and enthalpy-entropy compensation relationship were investigated; The enantioselectivities were calculated, among which ZnT(o-BocAla)APP to LeuOMe is as high as 6.9, which is the highest value reported in our system; The relationship between selectivity and temperature has been discussed, which showed that the selectivity will increase when the experimental temperature decreases, and it is expected to be useful to the application of chiral recognition; 1H NMR was investigated and the binding mode of this chiral recognition was revealed; CD spectrum of host-guest complexes was also investigated; Simulated annealing and quantum chemistry were in company with investigating the binding mode of this system theoretically.4. The recognition of DABCO by Zinc porphyrin-salen dimer ZnPSC10 was studied.1H NMR titration was used to study the association process of the system, considering that the ternary sandwich conformations are the stable conformations of this system; The respectively mensuration of thermodynamic parameters of the dimers formed by two different parts was presented first time; Molecular mechanics and quantum chemistry were in company with investigating the stable ternary sandwich conformations of this system theoretically.5. The recognition of three guest molecules pyridine, DABCO and pyrazine by Zinc porphyrin-salen dimer ZnPSC10 was studied. The association ability of three guests was in order pyridine>DABCO>pyrazine; The higher HOMO energy was, the stronger association ability of the guests were; Molecular mechanics and quantum chemistry were used to estimated the most stable conformations of this system.更多还原