本文選題：雙自由基 + 電子順磁共振　； 參考：《天津醫(yī)科大學(xué)》2017年碩士論文

【摘要】：目的:近年來(lái),由三芳基甲基(trityl,T)自由基和氮氧(nitroxide,N)自由基組成的一類雜化型TN雙自由基受到了廣泛關(guān)注。該類雙自由基具有獨(dú)特的物理化學(xué)性質(zhì),在諸多領(lǐng)域呈現(xiàn)很強(qiáng)的應(yīng)用前景,如生物分子結(jié)構(gòu)領(lǐng)域的自旋標(biāo)記物,氧化還原探針以及動(dòng)態(tài)核極化(DNP)試劑等。DNP是一種增強(qiáng)核磁共振靈敏性的有效方法,結(jié)合魔角旋轉(zhuǎn)固態(tài)核磁技術(shù)已被廣泛應(yīng)用于膜蛋白質(zhì)、淀粉樣蛋白、功能化多孔材料和納米顆粒等的結(jié)構(gòu)動(dòng)力學(xué)研究。類似于氮氧雙自由基,TN雙自由基的自旋-自旋相互作用是其最重要的理化性質(zhì)之一,也是決定其DNP性能的關(guān)鍵因素。諸多研究表明,雙自由基的自旋-自旋相互作用受多因素影響,如兩自旋電子間連接鏈的屬性(長(zhǎng)度、剛?cè)嵝?,自由基部分的構(gòu)象,環(huán)境因素(溫度、溶劑)等。因此,理論上可通過(guò)改變上述條件調(diào)控TN雙自由基的自旋-自旋相互作用強(qiáng)弱,進(jìn)而開(kāi)發(fā)性能更佳的TN雙自由基,增強(qiáng)其應(yīng)用潛質(zhì)。本人所在的課題組在TN雙自由基的自旋-自旋相互作用調(diào)控及其高場(chǎng)DNP應(yīng)用方面已經(jīng)開(kāi)展了深入研究,提出了調(diào)控其自旋-自旋相互作用的兩種方法:1)改變兩個(gè)自由基之間連接鏈的屬性;2)TN雙自由基與環(huán)糊精之間的主-客體超分子相互作用。在本工作中,我們闡述了利用自由基的手性調(diào)控TN雙自由基自旋-自旋相互作用強(qiáng)弱的方法,并研究了自旋-自旋相互作用強(qiáng)弱對(duì)DNP性能的影響。方法:本課題首先以L-脯氨酸和外消旋化合物2,2,5,5-四甲基-3-氨基-吡咯烷-1-氧自由基為原料通過(guò)酰胺縮合得到兩個(gè)非對(duì)映異構(gòu)體NP1和NP2;光學(xué)純氮氧自由基NP1和NP2與外消旋trityl自由基(CT-03,M/P構(gòu)型)共價(jià)偶聯(lián)后分別得到雙自由基的兩個(gè)非對(duì)映異構(gòu)體混合物TNT和TNL。采用制備HPLC方法得到了TNT的兩個(gè)光學(xué)純非對(duì)映異構(gòu)體TNT_1和TNT_2。隨后,采用EPR技術(shù)研究了溫度和溶劑對(duì)TNT和TNL及TNT_1和TNT_2的自旋-自旋相互作用的影響,用于揭示氮氧自由基和trityl自由基部分對(duì)其交換相互作用的影響。在此基礎(chǔ)上,進(jìn)一步考察了TNT和TNL的手性對(duì)其DNP增強(qiáng)性質(zhì)的影響。結(jié)果:合成得到了雙自由基的兩個(gè)非對(duì)映異構(gòu)體混合物TNT和TNL;TNT經(jīng)HPLC制備分離得到了相應(yīng)的兩個(gè)非對(duì)映異構(gòu)體TNT_1和TNT_2。采用上述方法研究了雙自由基TNT和TNL及TNT_1和TNT_2的手性對(duì)其自旋-自旋相互作用的影響,也考察了TNT和TNL的手性對(duì)其DNP增強(qiáng)性質(zhì)的影響。研究結(jié)果表明:1)室溫條件下,雙自由基TNT和TNL的EPR譜圖呈現(xiàn)較大差別;EPR譜圖模擬表明,TNT可用單組分進(jìn)行模擬,其交換相互作用(J)為421 G;相反,TNL僅能通過(guò)雙組分進(jìn)行模擬,其J值分別為12 G(88%)和171 G(12%);2)溶劑對(duì)雙自由基TNT和TNL的自旋交換相互作用有顯著影響,且雙自由基的交換相互作用與溶劑的介電常數(shù)呈負(fù)相關(guān);3)溫度對(duì)雙自由基TNT和TNL的自旋-自旋相互作用影響較大,低溫下TNT和TNL有相似的偶極相互作用,但交換相互作用明顯不同;4)TNT_1和TNT_2的自旋-自旋相互作用存在一定差異,溫度及溶劑對(duì)其自旋-自旋相互作用有適度影響;5)雙自由基TNT和TNL的DNP增強(qiáng)效果展現(xiàn)出明顯不同,表明相對(duì)弱的自旋-自旋相互作用有利于DNP增強(qiáng)效應(yīng)。結(jié)論:1)TNT和TNL的差異證實(shí)氮氧自由基部分的手性對(duì)TN雙自由基自旋-自旋相互作用及DNP增強(qiáng)有顯著影響;2)TNT_1和TNT_2的對(duì)比研究證明trityl自由基部分的M/P構(gòu)型對(duì)其自旋-自旋相互作用的影響較小;3)研究還證實(shí)雙自由基太強(qiáng)的交換相互作用對(duì)雙自由基的DNP增強(qiáng)效果不利。該研究對(duì)雙自由基自旋-自旋相互作用的調(diào)控及開(kāi)發(fā)性能更佳的DNP極化試劑提供了新思路和新方法,有望拓展TN雙自由基在磁共振和磁性材料領(lǐng)域的潛在應(yīng)用。
[Abstract]:Objective: in recent years, a class of hybrid TN double radicals, composed of three aryl methyl (trityl, T) free radicals and nitroxide (N) free radicals, has been widely concerned. This kind of double radical has unique physical and chemical properties, and presents a strong application foreground in many fields, such as spin markers in the field of biomolecular structure, redox The probe and the dynamic nuclear polarization (DNP) reagents, such as.DNP, are an effective method to enhance the sensitivity of nuclear magnetic resonance. The solid-state nuclear magnetic technique combined with the magic angle rotation has been widely used in the structural dynamics of membrane protein, amyloid, functionalized porous materials and nanoparticles. It is similar to the double radicals of nitrogen oxygen and the spin of the TN double radical. Spin interaction is one of the most important physical and chemical properties and a key factor in determining its DNP properties. Many studies have shown that the spin spin interaction of the double radicals is influenced by many factors, such as the properties of the two spin electrons (length, rigid flexibility), the conformation of the free radical part, the environmental factors (temperature, solvent), etc. In view of the above conditions, the spin spin interaction of TN double radicals can be regulated by changing the above conditions, and then the TN double radical with better performance can be developed to enhance the potential of its application. The research group I was located in the spin spin interaction of the TN double free radical and the high field DNP application side have been studied in depth, and the regulation and control have been put forward. Two methods of spin spin interaction: 1) change the properties of the chain between the two free radicals; 2) the interaction between the principal guest supramolecular interaction between the TN double radical and the cyclodextrin. In this work, we expound the method of using the chiral radicals to regulate the spin spin interaction of the TN double radicals and study the spin self. The effect of spin interaction strength on the performance of DNP. Methods: first of all, two non enantiomers NP1 and NP2 were obtained by amidation of L- proline and racemic compound 2,2,5,5- four methyl -3- amino pyrrolidine -1- oxygen radical, and optical pure nitrogen oxygen free radical NP1 and NP2 and racemic trityl free radical (CT-03, M/P configuration). Two non enantiomer mixtures TNT and TNL. with double free radicals were obtained after valence coupling, and two optically pure non enantiomers TNT_1 and TNT_2. were obtained by HPLC method. The effects of temperature and solvent on the spin self spin interaction of TNT and TNL, TNT_1 and TNT_2 were investigated by EPR technology, which was used to reveal the nitrogen and oxygen self. The effects of the radical and trityl radicals on their exchange interactions. On this basis, the effects of the chirality of TNT and TNL on their DNP enhancement properties were further investigated. Results: the synthesis of two non enantiomer mixtures of TNT and TNL with double radicals was synthesized, and TNT was separated by HPLC to obtain the corresponding two non enantiomers TNT_1 and TNT_2. has been used to study the effects of the chiral on the spin spin interaction of the two free radicals TNT and TNL, TNT_1 and TNT_2, and the effect of the chirality of TNT and TNL on its DNP enhancement. The results show that: 1) the EPR spectra of the dual radicals TNT and TNL are quite different at room temperature; EPR spectrum simulation shows that A single component is used to simulate the exchange interaction (J) is 421 G; on the contrary, the TNL can only be simulated by two components, and the J values are 12 G (88%) and 171 G (12%); 2) the solvent has a significant influence on the spin exchange interaction of the double free radical TNT and TNL, and the exchange interaction of the double radicals is negatively correlated with the dielectric constant of the solvent; 3) temperature The spin spin interaction of two free radicals TNT and TNL has great influence. At low temperature, TNT and TNL have similar dipole interactions, but the exchange interaction is obviously different. 4) there is a certain difference in spin spin interaction between TNT_1 and TNT_2, temperature and solvent have a moderate effect on its spin spin interaction; 5) D of TNT and TNL of double free radicals. The enhanced effect of NP shows a distinct difference, indicating that the relatively weak spin spin interaction is beneficial to the DNP enhancement effect. Conclusion: 1) the difference between TNT and TNL confirms that the chirality of the nitrogen and oxygen radicals has a significant influence on the spin spin interaction of the TN double radicals and the enhancement of DNP; and the contrast between TNT_1 and TNT_2 proves M/ of the trityl radical part. The P configuration has little effect on its spin spin interaction; 3) the study also confirmed that the strong exchange interaction of the double radicals is unfavorable to the DNP enhancement of the double radicals. This study provides new ideas and new methods for the regulation of spin spin interaction of the double radicals and the better development of DNP polarization reagents. It is expected to expand the TN double self. Potential applications in the field of magnetic resonance and magnetic materials.
【學(xué)位授予單位】：天津醫(yī)科大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：O621.146

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本文編號(hào)：2075336