基于双卟啉的手性超分子体系及三明治型分子转子体系
发布时间：2018-09-04 09:15
【摘要】：卟啉是一类典型的刚性共面型共轭大环分子,具有独特的电子结构和光电性能,同时拥有良好的光热稳定性以及易于裁剪修饰等特点,使其在化学、材料及生命科学等领域具有广泛的应用前景。卟啉类化合物一直是超分子化学和立体化学领域的重要研究对象之一。由于卟啉对结构变化、环境变化及外部刺激具有灵敏的电子和光学响应,所以经常被作为手性光学探针单元用于立体选择性分子识别体系的构筑。尤其是共价连接的双卟啉体系,其中预置的半刚性空腔不但有利于增强主-客体作用的选择性,同时使客体诱导的变构效应表达为两个卟啉单元之间的相对位置和取向变化,从而显著提高(手性)光学响应的灵敏度。另外,三明治型卟啉酞菁类金属配合物具有独特的三维共轭结构体系,其在分子半导体、非线性光学及分子磁学领域取得重要进展。在此类分子中,“夹心”配位的金属离子通过多重配位作用连接两个或多个刚性共轭配体,配体能够以金属离子为轴进行相对转动,构成一类新颖的分子转子体系。本论文主要设计合成了一系列联二萘连接的手性双卟啉分子,研究其分子内手性传递、分子间手性调控现象和对手性二胺的超分子识别作用。另一方面,设计合成了含有共价链连接双卟啉的三明治型稀土配合物的分子转子,研究了三层配合物分子中处在两个卟啉环之间的酞菁环的相对转动行为;通过配位金属离子的选择和连接基团的变化对其转动动力学特性进行了调控。主要研究内容如下:1.系列联二萘酚桥联双卟啉分子内的手性诱导和分子间手性调控研究了一系列手性双卟啉主体(H1-H3)的分子内手性诱导和分子间手性调控现象。三对对映异构体分别由锌卟啉和纯手性的(R)-或(S)-1,1'-联-2-萘酚(BINOL)通过醚键或酯基连接构成。所有双卟啉主体的CD光谱都呈现裂分的科顿效应,而且其CD信号符号与所用BINOL的立体结构一致。从H1到H3,随着BINOL和卟啉之间连接基团的长度和柔性的增加,其CD信号强度逐渐减弱。表明BINOL的手性被表达为两个卟啉单元之间的扭转排列,而且这种分子内手性诱导效应可以通过连接基团的长度和刚性进行调控。通过UV-Vis,1HNMR和CD光谱滴定研究了手性双卟啉主体(H1-H3)与非手性客体(BiPy)及手性客体[(S)-/(R)-DACH]之间的分子间手性调控现象。光谱滴定结果表明:1)BiPy和上述三对双卟啉主体均形成1:1配位的三明治型超分子络合物,其CD信号强度都有所减弱,而CD信号符号都没有变化;2)H1和(S)-/(R)-DACH形成1:2配位的开环结构,CD信号强度减弱而CD符号不变;3)H2和H3与(S)-/(R)-DACH都形成1:1配位的三明治型超分子结构,当主体与客体同手性时CD信号强度增强而符号不变,当主体与客体异手性时CD信号强度增强而且CD符号反转。此外,DFT量子化学理论模拟得到的优化分子构型与光谱滴定指认的配位模式一致,而且主客体络合前后两个卟啉单元之间距离和扭转角的变化趋势与其CD光谱的变化趋势相符合。2.联二萘桥联的双卟啉对二胺的手性识别在上一章研究结果的基础上,经过结构优化设计了一对新的手性双卟啉主体[(R)-/(S)-H1]用于二胺类客体[(R)-/(S)-DACH,(R)-/(S)-PPDA 和(R)-/(S)-DPEA]的手性识别。UV-Vis,CD和1HNMR光谱滴定表明,(R)-/(S)-DACH和(R)-/(S)-PPDA可以被包夹在该双卟啉主体的空腔内,通过双重Zn-N配位相互作用形成三明治型1:1络合物。该络合过程对手性二胺的立体构型有明显的CD光谱响应。(R)-/(S)-H1的手性识别作用也可以通过NMR滴定的方法检测到,其中对(R)-/(S)-DACH的不等价化学位移(△△δ)可以达到0.57ppm,手性识别能(△△G°)达到-4.02kJ mol-1。然而由于较大的位阻效应,另一对手性客体((R)-/(S)-DPEA)不能被包夹在手性双卟啉的空腔内形成三明治型配合物,因此(R)-/(S)-DPEA不能够被(R)-/(S)-H1识别。研究结果表明该手性双卟啉主体同时拥有优异的CD和NMR手性识别能力,而且其手性识别能力对配位模式具有依赖性。3.联二萘酚桥联的手性双卟啉铈配合物的合成及性质研究合成了三明治性手性双卟啉铈配合物(R)-/(S)-1和(R/(S)-2,其中两个卟啉环分别通过(R)-(+)-或(S)-(-)-1,1'-二-2-萘酚(BINOL)桥联。对(R)-/(S)-1和(R)-/(S)-2进行了光谱学和电化学表征。对映异构体之间呈现相互对称的CD光谱,在Soret带(R)-型异构体的CD信号为负而(S)-型异构体的CD信号为正;而且(R)-/(S)-1的CD信号强度比(R)-/(S)-2强。结果表明BINOL基团的C2-手性被传递到了双层配合物结构,表现为两个卟啉单元之间具有确定方向的扭转排列,而且其手性传递效率可以通过改变连接基团的长度进行调节。4.联二萘酚桥联的卟啉酞菁混杂三层稀土三明治型分子转子的构筑合成了联二萘酚连接的混杂卟啉酞菁稀土三明治型配合物(R)-/(S)-1和(R)-/(S)-2作为新型分子转子模型,处于中间的酞菁配体作为转子,而两侧由BINOL连接的两个卟啉单元作为定子。通过变温核磁(VT-NMR)实验研究酞菁配体的转动行为。通过对VT-NMR谱图的线型分析得到(R)-1在氘代甲苯和氘代三氯甲烷中的转动能垒分别为57.8 kJmol-1和60.2kJmol-1,(R)-2在氘代甲苯和氘代三氯甲烷中的转动能垒分别为50.0 kJ mol-1和44.1 kJ mol-1。表明通过改变配位的金属离子可以有效调控酞菁转子的转动行为。5.偶氮苯桥联的光控三明治型分子转子合成了偶氮苯桥连的混杂卟啉酞菁稀土三层三明治型配合物,利用偶氮苯基团的可逆光致顺-反异构性质,以期实现对处于分子中间的酞菁配体的转动行为进行调控。用电子吸收光谱和核磁共振光谱对其光致顺-反异构进行了研究,当用365 nm波长的光照射20分钟后,由全反式变为顺式占主导(cis/trans = 76:24)。分别测试了其在反式结构和顺式为主时的变温核磁谱图,表明反式结构时酞菁环的转动阻力较大,转速较慢;而顺式结构时转动阻力较小,转速较快。该结果为设计新型光调控分子转子提供了基础。
[Abstract]:Porphyrin is a typical rigid coplanar conjugated macrocyclic molecule with unique electronic structure and photoelectric properties. It has good photothermal stability and is easy to tailor and modify. Porphyrins have a wide range of applications in chemistry, materials and life sciences. Porphyrins have always been supramolecular chemistry and stereochemistry. Porphyrins are often used as chiral optical probe units in the construction of stereoselective molecular recognition systems because of their sensitive electronic and optical responses to structural changes, environmental changes and external stimuli. In addition, sandwich-type porphyrin phthalocyanine metal complexes have unique three-dimensional conjugated structure system, which is in the molecular semi-structure. Important progress has been made in the field of conductors, nonlinear optics and molecular magnetism. In these molecules, sandwich coordination metal ions connect two or more rigid conjugated ligands through multiple coordination interactions, and the ligands can rotate relative to the metal ions on the axis to form a novel class of molecular rotor systems. A series of binaphthalene-linked chiral bisporphyrins were synthesized to study their intramolecular chiral transfer, intermolecular chiral regulation and supramolecular recognition of chiral diamines. On the other hand, a sandwich-type rare earth complex with covalent chain-linked bisporphyrins was designed and synthesized. The relative rotation behavior of the phthalocyanine rings between the porphyrin rings was studied. The kinetics of the rotation was regulated by the choice of coordination metal ions and the change of ligand groups. The main contents are as follows: 1. Chiral induction and chiral regulation of a series of chiral bisporphyrins bridged by binaphthol were studied. Intramolecular chiral induction and intermolecular chiral regulation of (H1-H3). The three enantiomers are composed of zinc porphyrin and pure chiral (R) - or (S) - 1,1'-bi-2-naphthol (BINOL) via ether bonds or ester bonds, respectively. The CD spectra of all bisporphyrin hosts exhibit a split Cotton effect, and their CD signals bind to the stereo of the BINOL used. From H1 to H3, the CD signal intensity decreases with the increase of the length and flexibility of the ligand between BINOL and porphyrin. It shows that the chirality of BINOL is expressed as a torsional arrangement between two porphyrin units, and this intramolecular chiral induction effect can be modulated by the length and rigidity of the ligand. The intermolecular chiral regulation between chiral bisporphyrin host (H1-H3) and non-chiral guest (BiPy) and chiral guest [(S) - / (R) - DACH] was studied by MR and CD spectroscopic titration. The results showed that: 1) BiPy and the above three pairs of bisporphyrin host formed a 1:1 coordination sandwich supramolecular complex, and the CD signal intensity was weakened. Signal symbols remained unchanged; 2) H 1 and (S) - / (R) - DACH formed an open-loop structure with 1:2 coordination, and CD signal intensity weakened while CD symbol remained unchanged; 3) H2 and H3 and (S) - / (R) - DACH formed a sandwich supramolecular structure with 1:1 coordination, and CD signal intensity increased and symbol remained unchanged when the host and the guest were chiral; and CD signal was strong when the host and the guest were heterochromatic. In addition, the optimized molecular configuration simulated by DFT quantum chemical theory is consistent with the coordination pattern identified by spectrophotometric titration, and the variation trend of the distance and twist angle between the two porphyrin units before and after complexation conforms to the variation trend of CD spectrum. 2. Binaphthalene bridged diproporphyrin p-diamine On the basis of the results of the previous chapter, a novel chiral bisporphyrin host [(R) - / (S) - H1] for chiral recognition of diamine guest [(R) - / (S) - DACH, (R) - / (S) - PPDA and (R) - / (S) - DPEA] was designed by structural optimization. UV-Vis, CD and 1H NMR spectroscopic titration showed that, (R) - / (S) - DACH and (R) - / (S) - PPDA could be encapsulated in the bisporphyrin. A sandwich-type 1:1 complex is formed in the cavity of the main body of the porphyrin by double Zn-N coordination interaction. The complex process has obvious CD spectral response to the stereoconfiguration of chiral diamines. (R) - / (S) -H 1 chiral recognition can also be detected by NMR titration, in which the unequal chemical shifts (delta) to (R) - / (S) -DACH can be up to At 0.57 ppm, the chiral recognition energy (delta G degrees) reached - 4.02 kJ mol - 1. However, due to the large steric hindrance effect, the other chiral guest ((R) - / (S) - DPEA) could not be encapsulated in the cavity of chiral bisporphyrins to form sandwich complexes, so (R) - / (S) - DPEA could not be recognized by (R) - / (S) - H1. 3. Synthesis and characterization of chiral bisporphyrin cerium complexes bridged by binaphthol have been studied. Trimeric chiral bisporphyrin cerium complexes (R) - / (S) - 1 and (R / (S) - 2 have been synthesized. Two porphyrin rings pass through (R) - (+) - or (S) - (-) - 1, 1, 1, 2, respectively. '-bis-2-naphthol (BINOL) bridged. Spectroscopic and electrochemical characterizations of (R) - / (S) -1 and (R) - / (S) -2 were carried out. CD spectra of the enantiomers were symmetrical. CD signals of the (R) - type isomers in the Sorret band were negative and that of the (S) - type isomers were positive; and the CD signal intensity ratio of (R) - / (S) - 2 of (R) - / (S) - 1 was strong. C2-chirality is transferred to the double-layer complex structure, which is characterized by the twisted arrangement of two porphyrin units in a definite direction, and the chiral transfer efficiency can be adjusted by changing the length of the linked groups. 4. Binaphthol-bridged porphyrin-phthalocyanine hybrid triple-layer rare earth sandwich molecular rotor is synthesized. Rare earth sandwich complexes (R) - / (S) - 1 and (R) - / (S) - 2 of hybrid porphyrin phthalocyanines are used as new molecular rotor models. The intermediate phthalocyanine ligands are used as the rotor and the two porphyrin units connected by BINOL are used as the stators. The rotational behavior of the ligands is studied by variable temperature nuclear magnetic resonance (VT-NMR). The rotational energy barriers of (R) -1 in deuterated toluene and deuterated trichloromethane were 57.8 kJ mol-1 and 60.2 kJ mol-1, respectively. The rotational energy barriers of (R) -2 in deuterated toluene and deuterated trichloromethane were 50.0 kJ mol-1 and 44.1 kJ mol-1 kJ mol-1, respectively. It was shown that the rotational behavior of phthalocyanine rotors could be effectively controlled by changing the coordination metal ions. Azobenzene-bridged photocontrolled sandwich molecular rotors have been used to synthesize azobenzene-bridged hybrid porphyrin phthalocyanine rare earth triple-layer sandwich complexes. The reversible photoinduced cis-trans isomerization of azobenzene groups has been utilized to modulate the rotation behavior of phthalocyanine ligands in the middle of molecules. Electron absorption spectroscopy and nuclear magnetic resonance spectroscopy have been used. The photoinduced cis-trans isomerization was studied. After irradiation with light of 365 nm wavelength for 20 minutes, it changed from all trans to cis-dominant (cis/trans=76:24). The NMR spectra of trans-and cis-dominant phthalocyanines at different temperatures were measured. The results showed that the rotational resistance of trans-structure was higher and the rotational speed was slower than cis-structure. The resistance is small and the speed is faster. The results provide a basis for designing a new type of light controlled molecular rotor.
【学位授予单位】：北京科技大学
【学位级别】：博士
【学位授予年份】：2018
【分类号】：O641
本文编号：2221647
[Abstract]:Porphyrin is a typical rigid coplanar conjugated macrocyclic molecule with unique electronic structure and photoelectric properties. It has good photothermal stability and is easy to tailor and modify. Porphyrins have a wide range of applications in chemistry, materials and life sciences. Porphyrins have always been supramolecular chemistry and stereochemistry. Porphyrins are often used as chiral optical probe units in the construction of stereoselective molecular recognition systems because of their sensitive electronic and optical responses to structural changes, environmental changes and external stimuli. In addition, sandwich-type porphyrin phthalocyanine metal complexes have unique three-dimensional conjugated structure system, which is in the molecular semi-structure. Important progress has been made in the field of conductors, nonlinear optics and molecular magnetism. In these molecules, sandwich coordination metal ions connect two or more rigid conjugated ligands through multiple coordination interactions, and the ligands can rotate relative to the metal ions on the axis to form a novel class of molecular rotor systems. A series of binaphthalene-linked chiral bisporphyrins were synthesized to study their intramolecular chiral transfer, intermolecular chiral regulation and supramolecular recognition of chiral diamines. On the other hand, a sandwich-type rare earth complex with covalent chain-linked bisporphyrins was designed and synthesized. The relative rotation behavior of the phthalocyanine rings between the porphyrin rings was studied. The kinetics of the rotation was regulated by the choice of coordination metal ions and the change of ligand groups. The main contents are as follows: 1. Chiral induction and chiral regulation of a series of chiral bisporphyrins bridged by binaphthol were studied. Intramolecular chiral induction and intermolecular chiral regulation of (H1-H3). The three enantiomers are composed of zinc porphyrin and pure chiral (R) - or (S) - 1,1'-bi-2-naphthol (BINOL) via ether bonds or ester bonds, respectively. The CD spectra of all bisporphyrin hosts exhibit a split Cotton effect, and their CD signals bind to the stereo of the BINOL used. From H1 to H3, the CD signal intensity decreases with the increase of the length and flexibility of the ligand between BINOL and porphyrin. It shows that the chirality of BINOL is expressed as a torsional arrangement between two porphyrin units, and this intramolecular chiral induction effect can be modulated by the length and rigidity of the ligand. The intermolecular chiral regulation between chiral bisporphyrin host (H1-H3) and non-chiral guest (BiPy) and chiral guest [(S) - / (R) - DACH] was studied by MR and CD spectroscopic titration. The results showed that: 1) BiPy and the above three pairs of bisporphyrin host formed a 1:1 coordination sandwich supramolecular complex, and the CD signal intensity was weakened. Signal symbols remained unchanged; 2) H 1 and (S) - / (R) - DACH formed an open-loop structure with 1:2 coordination, and CD signal intensity weakened while CD symbol remained unchanged; 3) H2 and H3 and (S) - / (R) - DACH formed a sandwich supramolecular structure with 1:1 coordination, and CD signal intensity increased and symbol remained unchanged when the host and the guest were chiral; and CD signal was strong when the host and the guest were heterochromatic. In addition, the optimized molecular configuration simulated by DFT quantum chemical theory is consistent with the coordination pattern identified by spectrophotometric titration, and the variation trend of the distance and twist angle between the two porphyrin units before and after complexation conforms to the variation trend of CD spectrum. 2. Binaphthalene bridged diproporphyrin p-diamine On the basis of the results of the previous chapter, a novel chiral bisporphyrin host [(R) - / (S) - H1] for chiral recognition of diamine guest [(R) - / (S) - DACH, (R) - / (S) - PPDA and (R) - / (S) - DPEA] was designed by structural optimization. UV-Vis, CD and 1H NMR spectroscopic titration showed that, (R) - / (S) - DACH and (R) - / (S) - PPDA could be encapsulated in the bisporphyrin. A sandwich-type 1:1 complex is formed in the cavity of the main body of the porphyrin by double Zn-N coordination interaction. The complex process has obvious CD spectral response to the stereoconfiguration of chiral diamines. (R) - / (S) -H 1 chiral recognition can also be detected by NMR titration, in which the unequal chemical shifts (delta) to (R) - / (S) -DACH can be up to At 0.57 ppm, the chiral recognition energy (delta G degrees) reached - 4.02 kJ mol - 1. However, due to the large steric hindrance effect, the other chiral guest ((R) - / (S) - DPEA) could not be encapsulated in the cavity of chiral bisporphyrins to form sandwich complexes, so (R) - / (S) - DPEA could not be recognized by (R) - / (S) - H1. 3. Synthesis and characterization of chiral bisporphyrin cerium complexes bridged by binaphthol have been studied. Trimeric chiral bisporphyrin cerium complexes (R) - / (S) - 1 and (R / (S) - 2 have been synthesized. Two porphyrin rings pass through (R) - (+) - or (S) - (-) - 1, 1, 1, 2, respectively. '-bis-2-naphthol (BINOL) bridged. Spectroscopic and electrochemical characterizations of (R) - / (S) -1 and (R) - / (S) -2 were carried out. CD spectra of the enantiomers were symmetrical. CD signals of the (R) - type isomers in the Sorret band were negative and that of the (S) - type isomers were positive; and the CD signal intensity ratio of (R) - / (S) - 2 of (R) - / (S) - 1 was strong. C2-chirality is transferred to the double-layer complex structure, which is characterized by the twisted arrangement of two porphyrin units in a definite direction, and the chiral transfer efficiency can be adjusted by changing the length of the linked groups. 4. Binaphthol-bridged porphyrin-phthalocyanine hybrid triple-layer rare earth sandwich molecular rotor is synthesized. Rare earth sandwich complexes (R) - / (S) - 1 and (R) - / (S) - 2 of hybrid porphyrin phthalocyanines are used as new molecular rotor models. The intermediate phthalocyanine ligands are used as the rotor and the two porphyrin units connected by BINOL are used as the stators. The rotational behavior of the ligands is studied by variable temperature nuclear magnetic resonance (VT-NMR). The rotational energy barriers of (R) -1 in deuterated toluene and deuterated trichloromethane were 57.8 kJ mol-1 and 60.2 kJ mol-1, respectively. The rotational energy barriers of (R) -2 in deuterated toluene and deuterated trichloromethane were 50.0 kJ mol-1 and 44.1 kJ mol-1 kJ mol-1, respectively. It was shown that the rotational behavior of phthalocyanine rotors could be effectively controlled by changing the coordination metal ions. Azobenzene-bridged photocontrolled sandwich molecular rotors have been used to synthesize azobenzene-bridged hybrid porphyrin phthalocyanine rare earth triple-layer sandwich complexes. The reversible photoinduced cis-trans isomerization of azobenzene groups has been utilized to modulate the rotation behavior of phthalocyanine ligands in the middle of molecules. Electron absorption spectroscopy and nuclear magnetic resonance spectroscopy have been used. The photoinduced cis-trans isomerization was studied. After irradiation with light of 365 nm wavelength for 20 minutes, it changed from all trans to cis-dominant (cis/trans=76:24). The NMR spectra of trans-and cis-dominant phthalocyanines at different temperatures were measured. The results showed that the rotational resistance of trans-structure was higher and the rotational speed was slower than cis-structure. The resistance is small and the speed is faster. The results provide a basis for designing a new type of light controlled molecular rotor.
【学位授予单位】：北京科技大学
【学位级别】：博士
【学位授予年份】：2018
【分类号】：O641
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