水溶性磺酸钠苯基卟啉及其金属配合物共价与非共价修饰多壁碳纳米管的研究

合成了meso-四(4-磺酸钠苯基)卟啉及其Zn, Cu, Mn配合物, 通过共价与非共价的方法将其分别修饰到多壁碳纳米管上. 采用红外光谱对产物结构进行表征|通过透射电镜(TEM)考察了卟啉-多壁碳纳米管复合物的形貌特征|通过紫外光谱、荧光光谱对比分析了两类复合物, 发现在卟啉与多壁碳纳米管之间存在较强的电子效应, 同时发现非共价修饰的卟啉-碳纳米管复合物的荧光淬灭率更高|热重分析(TGA)表明非共价的卟啉-碳纳米管复合物中卟啉的含量比较高. 对修饰后的复合物进行了溶解性测试, 结果表明共价修饰的复合物在水中有较好的溶解性和分散性.     

氨基卟啉共价化学修饰多壁碳纳米管

合成了5-(4-氨基)苯基-10,15,20-三苯基卟啉及其铜配合物, 通过化学键将氨基卟啉与活化的多壁碳纳米管(MWNT)发生酰胺化反应, 从而得到卟啉有机共价化学修饰的多壁碳纳米管的复合物. 通过红外光谱对产物的化学结构进行了表征, 证实了复合物体系中酰胺反应的发生. 紫外可见光吸收光谱和荧光光谱分析确定了卟啉与多壁碳纳米管间存在强烈的电子效应. 通过透射电镜(TEM)观察了产物的形貌特征, 发现碳纳米管壁上连接上了氨基卟啉小分子, 进一步证实了酰胺化反应的发生.     

金属卟啉有机共价和非共价修饰多壁碳纳米管

合成了5-(4-羟基苯基)-10,15,20-三苯基卟啉锌配合物, 与活化的多壁碳纳米管(MWNT)发生酯化反应, 从而得到金属卟啉有机共价化学修饰的多壁碳纳米管复合物; 利用金属卟啉环上的π电子与多壁碳纳米管管壁上的π电子通过π-π堆积效应, 得到金属卟啉有机非共价修饰的多壁碳纳米管复合物. 通过透射电镜(TEM)考察了金属卟啉-多壁碳纳米管复合物的形貌特征; 通过红外光谱对产物的化学结构进行了表征; 通过紫外光谱、荧光光谱和热失重分析(TGA)对比分析了两类复合物, 发现非共价修饰的金属卟啉-碳纳米管复合物的荧光淬灭率更高, 非共价修饰的金属卟啉-碳纳米管复合物中卟啉的含量比较高.     

金属卟啉化学共价和非共价修饰多壁碳纳米管

合成了5-(4-羟基苯基)-10,15,20-三苯基卟啉锌配合物,与活化的多壁碳纳米管(MWNT)发生酯化反应,从而得到金属卟啉有机共价化学修饰的多壁碳纳米管复合物;利用金属卟啉环上的π电子与多壁碳纳米管管壁上的π电子通过π-π堆积效应,得到金属卟啉有机非共价修饰的多壁碳纳米管复合物.通过透射电镜(TEM)考察了金属卟啉-多壁碳纳米管复合物的形貌特征;通过红外光谱对产物的化学结构进行了表征;通过紫外光谱、荧光光谱和热失重分析(TGA)对比分析了两类复合物,发现非共价修饰的金属卟啉-碳纳米管复合物的荧光淬灭率更高,非共价修饰的金属卟啉-碳纳米管复合物中卟啉的含量比较高.     

meso-四(4-酰肼基苯基)卟啉及其金属配合物共价和非共价修饰多壁碳纳米管

采用新方法合成了meso-四(4-酰肼基苯基)卟啉及其金属配合物, 通过化学键将酰肼卟啉上的酰肼基与活化的多壁碳纳米管(MWNTs)发生酰胺化反应, 从而得到卟啉共价化学修饰的多壁碳纳米管复合物; 利用卟啉环上的π电子与多壁碳纳米管管壁上的π电子通过π-π堆积效应, 得到卟啉非共价化学修饰的碳纳米管复合物. 通过红外光谱、紫外和荧光光谱对比分析, 发现在卟啉与碳纳米管间存在强烈的电子效应, 且非共价修饰的卟啉-碳纳米管复合物的荧光猝灭率更高.     

卟啉-碳纳米管复合物研究进展

碳纳米管是具有一维纳米结构的新型纳米材料,具有许多独特的物理、化学性质.卟啉对可见光具有强烈吸收,其大π共轭体系使其具有良好的电子给予能力,可作为人工光合作用体系的光捕捉单元.将具有电子接受能力的碳纳米管与卟啉结合起来,通过卟啉对碳纳米管进行共价和非共价修饰,可以改善碳纳米管在溶剂中的溶解分散性能,同时实现卟啉和碳纳米管之间有效的电子传递,形成具有独特光电和光学性质卟啉-碳纳米管复合物.该类物质具备良好的应用前景,是碳纳米管和卟啉研究中的热点.就近年来该类复合物的构筑方法及性质研究等方面的进展进行了综述.     

非离子型水溶性卟啉功能化单壁碳纳米管的研究

合成了两种非离子型水溶性卟啉分子,并利用它们对单壁碳纳米管(SWNTs)进行了非共价表面修饰。功能化后SWNTs能够在水中均匀分散。紫外-可见光谱、荧光光谱、透射电镜的测试结果均证明非离子型水溶性卟啉分子与SWNTs之间存在强烈的相互作用。其中,含有柔性烷基取代链的卟啉分子因与SWNTs之间存在π-π和疏水双重相互作用,所形成的复合物在水中表现出更好的分散稳定性。这种既具有水溶性又具有生物相容性和良好稳定性的功能化SWNTs,在生物医药领域具有潜在的应用前景。     

5-氟尿嘧啶修饰卟啉的合成及抗肿瘤活性

合成了一种5-氟尿嘧啶修饰的自由卟啉(5-[2-(5-氟尿嘧啶-3-基)乙氧基苯基]-10,15,20-三(4-甲氧基苯基)卟啉)及其2种金属卟啉配合物:5-[2-(5-氟尿嘧啶-3-基)乙氧基苯基]-10,15,20-三(4-甲氧基苯基)锰卟啉和5-[2-(5-氟尿嘧啶-3-基)乙氧基苯基]-10,15,20-三(4-甲氧基苯基)锌卟啉。 通过紫外可见光谱(UV-Vis)、红外光谱(IR)和核磁共振谱氢谱(¹H NMR)对目标化合物进行了结构表征。 用噻唑蓝法(MTT法)测定了自由卟啉、锰卟啉及锌卟啉分别对肺腺癌细胞株A549、肝癌细胞株Bel7402和人结肠癌细胞株HCT-8的抑制活性。 其中,锰卟啉对人结肠癌细胞株HCT-8的半抑制浓度为IC₅₀为17.8 mg/L,具有一定的细胞毒作用。     

吡硫醇在单壁碳纳米管修饰电极上电化学行为的研究

研究了吡硫醇在单壁碳纳米管修饰电极上的电化学行为,提出了一种检测吡硫醇的电化学方法.在0.1 mol/L的NaAc-HAc(pH 4.0)缓冲溶液中,吡硫醇在单壁碳纳米管修饰电极上出现一灵敏的氧化峰,峰电位位于0094 V处.与裸玻碳电极相比,单壁碳纳米管修饰电极显著提高了吡硫醇的氧化峰电流.在最佳实验条件下,吡硫醇浓度在9.9×10~(-6)～5.7×10~(-4) mol/L范围内与峰电流呈良好的线性关系,检出限为2.98×10~(-7) mol/L.吡硫醇在单壁碳纳米管修饰电极上的氧化过程受吸附控制,为1电子2质子的过程.     

手性Boc保护氨基酸修饰卟啉的合成及谱学研究

合成了α,α,α,β-四-[邻(叔丁氧羰丙氨酸)氨基苯基]卟啉H₂T(o-BocAla)APP(1)及其锌()配合物ZnT(o-BocAla)APP(Zn^-1),α,α,α,β-四-[邻(叔丁氧羰苏氨酸)氨基苯基]卟啉H₂T(o-BocThr)APP(2)及其锌(Ⅱ)配合物ZnT(o-BocThr)APP(Zn-2),α,α,α,β-四-[邻(叔丁氧羰酪氨酸)氨基苯基]卟啉H₂T(o-BocTyr)APP(3)及其锌()配合物ZnT(o-BocTyr)APP(Zn-3)等6种叔丁氧羰保护氨基酸修饰的卟啉.用元素分析、核磁共振、红外光谱、紫外-可见光谱以及圆二色谱等手段对其组成的结构进行了表征,并对其谱学性质进行了研究.     

Multi-triphenylamine-substituted porphyrin-fullerene conjugates as charge stabilizing "antenna-reaction center" mimics

A new concept of charge stabilization via delocalization of the pi-cation radical species over the donor macrocycle substituents in a relatively simple donor-acceptor bearing multimodular conjugates is reported. The newly synthesized multimodular systems were composed of three covalently linked triphenylamine entities at the meso position of the porphyrin ring and one fulleropyrrolidine at the fourth meso position. The triphenylamine entities were expected to act as energy transferring antenna units and to enhance the electron donating ability of both free-base and zinc(II) porphyrin derivatives of these pentads. Appreciable electronic interactions between the meso-substituted triphenylamine entities and the porphyrin pi-system were observed, and as a consequence, these moieties acted together as an electron-donor while the fullerene moiety acted as an electron-acceptor in the multimodular conjugates. In agreement with the spectral and electrochemical results, the computational studies performed by the DFT B3LYP/3-21G(*) method revealed delocalization of the frontier highest occupied molecular orbital (HOMO) over the triphenylamine entities in addition to the porphyrin macrocycle. Free-energy calculations suggested that the light-induced processes from the singlet excited state of porphyrins are exothermic in the investigated multimodular conjugates. The occurrence of photoinduced charge-separation and charge-recombination processes was confirmed by the combination of time-resolved fluorescence and nanosecond transient absorption spectral measurements. Charge-separated states, on the order of a few microseconds, were observed as a result of the delocalization of the pi-cation radical species over the porphyrin macrocycle and the meso-substituted triphenylamine entities. The present study successfully demonstrates a novel approach of charge-stabilization in donor-acceptor multimodular conjugates.     

Photocatalytic Hydrogen Evolution Based on Efficient Energy and Electron Transfers in Donor–Bridge–Acceptor Multibranched‐Porphyrin‐Functionalized Platinum Nanocomposites

Two donor–bridge–acceptor conjugates (5,10,15,20‐tetrakis[4‐(N,N‐diphenylaminobenzoate)phenyl] porphyrin (TPPZ) and 5,10,15,20‐tetrakis[4‐(N,N‐diphenylaminostyryl)phenyl] porphyrin (TPPX)) were covalently linked to triphenylamine (TPA) at the meso‐position of porphyrin ring. The triphenylamine entities were expected to act as energy donors and the porphyrins to act as an energy acceptor. In this paper, we report on the synthesis of these multibranched‐porphyrin‐functionalized Pt nanocomposites. The conjugates used here not only served as a stabilizer to prevent agglomeration of Pt nanoparticles, but also as a light‐harvesting photosensitizer. The occurrence of photoinduced electron‐transfer processes was confirmed by time‐resolved fluorescence and photoelectrochemical spectral measurements. The different efficiencies for energy and electron transfer in the two multibranched porphyrins and the functionalized Pt nanocomposites were attributed to diverse covalent linkages. Moreover, in the reduction of water to produce H₂, the photocatalytic activity of the Pt nanocomposite functionalized by TPPX, in which the triphenylamine and porphyrin moieties are bonded through an ethylene bridge, was much higher than that of the platinum nanocomposite functionalized by TPPZ, in which the two moieties are bonded through an ester. This investigation demonstrates the fundamental advantages of constructing donor–bridge–acceptor conjugates as highly efficient photosensitizers based on efficient energy and electron transfer.     

Syntheses and excitation transfer studies of near-orthogonal free-base porphyrin-ruthenium phthalocyanine dyads and pentad

A new series of molecular dyads and pentad featuring free-base porphyrin and ruthenium phthalocyanine have been synthesized and characterized. The synthetic strategy involved reacting free-base porphyrin functionalized with one or four entities of phenylimidazole at the meso position of the porphyrin ring with ruthenium carbonyl phthalocyanine followed by chromatographic separation and purification of the products. Excitation transfer in these donor-acceptor polyads (dyad and pentad) is investigated in nonpolar toluene and polar benzonitrile solvents using both steady-state and time-resolved emission techniques. Electrochemical and computational studies suggested that the photoinduced electron transfer is a thermodynamically unfavorable process in nonpolar media but may take place in a polar environment. Selective excitation of the donor, free-base porphyrin entity, resulted in efficient excitation transfer to the acceptor, ruthenium phthalocyanine, and the position of imidazole linkage on the free-base porphyrin could be used to tune the rates of excitation transfer. The singlet excited Ru phthalocyanine thus formed instantly relaxed to the triplet state via intersystem crossing prior to returning to the ground state. Kinetics of energy transfer (k(ENT)) was monitored by performing transient absorption and emission measurements using pump-probe and up-conversion techniques in toluene, respectively, and modeled using a F?rster-type energy transfer mechanism. Such studies revealed the experimental k(ENT) values on the order of 10(10)-10(11) s(-1), which readily agreed with the theoretically estimated values. Interestingly, in polar benzonitrile solvent, additional charge transfer interactions in the case of dyads but not in the case of pentad, presumably due to the geometry/orientation consideration, were observed.     

Photocatalytic hydrogen evolution based on efficient energy and electron transfers in donor-bridge-acceptor multibranched-porphyrin-functionalized platinum nanocomposites

Two donor-bridge-acceptor conjugates (5,10,15,20-tetrakis[4-(N,N-diphenylaminobenzoate)phenyl] porphyrin (TPPZ) and 5,10,15,20-tetrakis[4-(N,N-diphenylaminostyryl)phenyl] porphyrin (TPPX)) were covalently linked to triphenylamine (TPA) at the meso-position of porphyrin ring. The triphenylamine entities were expected to act as energy donors and the porphyrins to act as an energy acceptor. In this paper, we report on the synthesis of these multibranched-porphyrin-functionalized Pt nanocomposites. The conjugates used here not only served as a stabilizer to prevent agglomeration of Pt nanoparticles, but also as a light-harvesting photosensitizer. The occurrence of photoinduced electron-transfer processes was confirmed by time-resolved fluorescence and photoelectrochemical spectral measurements. The different efficiencies for energy and electron transfer in the two multibranched porphyrins and the functionalized Pt nanocomposites were attributed to diverse covalent linkages. Moreover, in the reduction of water to produce H(2), the photocatalytic activity of the Pt nanocomposite functionalized by TPPX, in which the triphenylamine and porphyrin moieties are bonded through an ethylene bridge, was much higher than that of the platinum nanocomposite functionalized by TPPZ, in which the two moieties are bonded through an ester. This investigation demonstrates the fundamental advantages of constructing donor-bridge-acceptor conjugates as highly efficient photosensitizers based on efficient energy and electron transfer.     

Diameter‐Sorted SWCNT–Porphyrin and SWCNT–Phthalocyanine Conjugates for Light‐Energy Harvesting

A non‐covalent double‐decker binding strategy is employed to construct functional supramolecular single‐wall carbon nanotubes (SWCNT)–tetrapyrrole hybrids capable of undergoing photoinduced electron transfer and performing direct conversion of light into electricity. To accomplish this, two semiconducting SWCNTs of different diameters (6,5 and 7,6) were modified via π–π stacking of pyrene functionalized with an alkyl ammonium cation (PyrNH₃⁺). Such modified nanotubes were subsequently assembled via dipole–cation binding of zinc porphyrin with one ( 1 ) or four benzo‐18‐crown‐6 cavities ( 2 ) or phthalocyanine with four benzo‐18‐crown‐6 cavities at the ring periphery ( 3 ), employed as visible‐light photosensitizers. Upon charactering the conjugates using TEM and optical techniques, electron transfer via photoexcited zinc porphyrin and phthalocyanine was investigated using time‐resolved emission and transient absorption techniques. Higher charge‐separation efficiency is established for SWCNT(7,6) with a narrow band gap than the thin SWCNT(6,5) with a wide band gap. Photoelectrochemical studies using FTO/SnO₂ electrodes modified with these donor–acceptor conjugates unanimously demonstrated the ability of these conjugates to convert light energy into electricity. The photocurrent generation followed the trend observed for charge separation, that is, incident‐photon‐to‐current efficiency (IPCE) of a maximum of 12 % is achieved for photocells with FTO/SnO₂/SWCNT(7,6)/PyrNH₃⁺: 1 .     

Dendrimer-functionalized single-wall carbon nanotubes: synthesis, characterization, and photoinduced electron transfer

We describe the synthesis and characterization of a series of single-wall carbon nanotubes (SWNTs) functionalized with polyamidoamine dendrimers. Importantly, the dendrimers are linked directly to the SWNT surface using a divergent methodology. This approach allows the number of functional groups on the nanotubes to be increased without provoking significant damage to the conjugated pi-system of the SWNTs. Several tetraphenylporphyrin moieties can be linked to the periphery of the dendrimers, and the photophysical properties of the resulting nanoconjugates have been investigated with a series of steady-state and time-resolved spectroscopy. The fluorescence kinetics provide evidence for two transient decays, one very short-lived (i.e., 0.04 +/- 0.01 ns) and one long-lived (i.e., 8.6 +/- 1.2 ns). A possible explanation is that some porphyrin units do not interact with the nanotubes, thus exhibiting a fluorescence lifetime similar to that of the free porphyrin. Complementary transient absorption measurements not only corroborate the fast decay of the photoexcited tetraphenylporphyrin but also confirm that intraconjugate charge separation evolves from the excited porphyrin to the SWNTs.     

Zinc phthalocyanine π-conjugately linked with electron-withdrawing benzothiadiazole towards broad absorption

New zinc phthalocyanine, peripherally functionalized with eight electron-withdrawing benzothiadiazole moieties through alkynic bond linkage, has been designed and synthesized. It was found that DBU acts as a ligand to coordinate with the central zinc ion at the axial direction. By this strategy, not only broad absorption covering the range of 300 ~ 900 nm, but also good solubility in common organic solvents and amorphous stability were achieved, making it an attractive candidate for potential application in solution processed small molecule-based organic photovoltaic devices.     

Photosynthetic reaction center mimicry of a "special pair" dimer linked to electron acceptors by a supramolecular approach: self-assembled cofacial zinc porphyrin dimer complexed with fullerene(s)

Biomimetic bacterial photosynthetic reaction center complexes have been constructed using well-defined self-assembled supramolecular approaches. The "special pair" donor, a cofacial porphyrin dimer, was formed via potassium ion induced dimerization of meso-(benzo-[15]crown-5)porphyrinatozinc. The dimer was subsequently self-assembled with functionalized fullerenes via axial coordination and crown ether-alkyl ammonium cation complexation to form the donor-acceptor pairs, mimicking the noncovalently bound entities of the photosynthetic reaction center. The adopted self-assembly methodology yielded supramolecular complexes of higher stability, with defined geometry and orientation. Efficient forward electron transfer from the singlet excited zinc porphyrin dimer to the fullerene entity and relatively slow reverse electron transfer, important steps in the photosynthetic light energy conversion have been achieved in these novel biomimetic model systems.     

Synthesis and electropolymerization of a perylenebisimide-functionalized 3,4-ethylenedioxythiophene (EDOT) derivative

[reaction: see text] We have developed a convenient and straightforward procedure for the preparation of functionalized 3,4-ethylenedioxythiophene (EDOT) systems by using a new chloromethyl-EDOT derivative as a versatile synthon. Based on this procedure, novel suitably functionalized perylenetetracarboxylic diimide (PDI) dye derivatives covalently linked to 3,4-ethylenedioxythiophene moieties have been synthesized and electrochemically polymerized to yield a donor-acceptor PEDOT derivative with an enhanced absorption cross-section.