水杨酸键联卟啉的合成及与牛血清白蛋白的相互作用

以溴代烷氧基苯基卟啉(1)为原料与水杨酸作用,分别得到了化合物2和3,再与醋酸钴反应,得到了钴卟啉配合物4和5.新化合物分别由¹HNMR,IR,UV-Vis,MS和元素分析确证.同时,利用荧光光谱考察了金属卟啉与牛血清白蛋白的相互作用.     

Expanding the porphyrin pi-system by fusion with anthracene

Synthesis of beta,meso,beta-anthracene triply fused and beta,meso-anthracene doubly fused porphyrins has been achieved via oxidative intramolecular ring closure of meso-(9-anthryl)porphyrins and meso-(1-anthryl)porphyrins, respectively. Fusion was only possible when the anthracene carried electron-donating alkoxy substituents. The fused porphyrins exhibit strongly red-shifted UV-vis absorption spectra and reduced electrochemical HOMO-LUMO gaps (relative to the unfused tetraaryl porphyrin precursor).     

One-pot synthesis of nickel porphyrins with 2-pyridine-acetyl substituents: the unexpected Sonogashira cross-coupling products

Nickel porphyrins with 2-pyridine-acetyl substituents were synthesized in one step by the Sonogashira cross-coupling method. The structures of the products were determined by elemental analysis, ¹H NMR, UV-Vis, and X-ray spectroscopic techniques. It is suggested that cross-coupling bromonated nickel porphyrins with 2-pyridine-ethyne first yielded nickel porphyrins with 2-pyridine-ethynyl substituents, followed by in situ hydrolysis to the final products, nickel porphyrins with 2-pyridine-acetyl substituents.     

Porphyrins fused with unactivated polycyclic aromatic hydrocarbons

A systematic study of the preparation of porphyrins with extended conjugation by meso,β-fusion with polycyclic aromatic hydrocarbons (PAHs) is reported. The meso-positions of 5,15-unsubstituted porphyrins were readily functionalized with PAHs. Ring fusion using standard Scholl reaction conditions (FeCl(3), dichloromethane) occurs for perylene-substituted porphyrins to give a porphyrin β,meso annulated with perylene rings (0.7:1 ratio of syn and anti isomers). The naphthalene, pyrene, and coronene derivatives do not react under Scholl conditions but are fused using thermal cyclodehydrogenation at high temperatures, giving mixtures of syn and anti isomers of the meso,β-fused porphyrins. For pyrenyl-substituted porphyrins, a thermal method gives synthetically acceptable yields (>30%). Absorption spectra of the fused porphyrins undergo a progressive bathochromic shift in a series of naphthyl (λ(max) = 730 nm), coronenyl (λ(max) = 780 nm), pyrenyl (λ(max) = 815 nm), and perylenyl (λ(max) = 900 nm) annulated porphyrins. Despite being conjugated with unsubstituted fused PAHs, the β,meso-fused porphyrins are more soluble and processable than the parent nonfused precursors. Pyrenyl-fused porphyrins exhibit strong fluorescence in the near-infrared (NIR) spectral region, with a progressive improvement in luminescent efficiency (up to 13% with λ(max) = 829 nm) with increasing degree of fusion. Fused pyrenyl-porphyrins have been used as broadband absorption donor materials in photovoltaic cells, leading to devices that show comparatively high photovoltaic efficiencies.     

The reaction of porphyrins with organolithium reagents

Porphyrins react readily with organolithium reagents, preferentially in the meso positions. The overall reaction is a nucleophilic substitution and proceeds via initial reaction of the organic nucleophile with a meso carbon yielding an anionic species which is hydrolyzed to a porphodimethene (5,15-dihydroporphyrin), formally constituting an addition reaction to two Cm positions. Subsequent oxidation with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) yields meso-substituted porphyrins. The reaction is highly versatile as it is accomplished in high, often quantitative yields with various alkyl or aryl lithium reagents. In addition, LiR can be used for reaction with a variety of metal complexes (best with NiII, but also with ZnII, CuII, and CoII) and most useful with free base porphyrins. Similarly beneficial this reaction can be used in sequence for the introduction of 1, 2, 3, or 4 (different) meso substituents giving for the first time an entry into any desired meso-substituted porphyrin. If meso-substituted porphyrins are used, reaction with LiR can be used for either the preparation of phlorins (already known reaction), porphodimethenes (5,15-dihydroporphyrins, including those with exocyclic double bonds, for example, 5(1),5(2)-didehydroporphyrins) or chlorins (2,3-dihydroporphyrins) depending on the substituent type in the reactant porphyrins. Thus, this reaction presents a generally applicable method for the facile and versatile functionalization of porphyrins.     

Capillary electrophoresis of urinary porphyrins with absorbance and fluorescence detection

Urinary porphyrins are separated in a 72 cm x 50 microns I.D. fused-silica capillary by micellar electrokinetic capillary chromatography with 100 mM sodium dodecyl sulfate and 20 mM 3-(cyclohexylamino)-1-propanesulfonic acid at pH 11. Detection is accomplished by absorbance at 400 nm or fluorescence with excitation at 400 nm and emission at wavelengths above 550 nm. Substantial trace enrichment is found for porphyrins in urine samples or for porphyrin standards prepared without surfactant in the injection buffer. Limits of detection are in the 100 pmol/ml concentration range with an optimized fluorescence system. The method is shown suitable for the determination of porphyrins in clinical urine specimens. Comparisons are made between electrophoretic and chromatographic methods for the separation and detection of urinary porphyrins.     

Efficient light-harvesting antenna with a multi-porphyrin cascade

A light-harvesting antenna 1 comprising three varieties of porphyrins, each having a different number of ethynyl groups at its meso positions, was designed and synthesized. Antenna 1 exhibits intense absorption throughout the visible region up to 700 nm. Steady-state and time-resolved fluorescence studies showed that singlet-excited-state energy transfer occurs from the peripheral porphyrins to the central porphyrin with >90% efficiency and rate constants on the order of 10(10) s(-1).     

Modular self-assembled multiporphyrin cages with tunable shape

Three new molecular cages-a trigonal prism (2) and two cubic-shaped boxes of increasing size (3, 4)-featuring as many as 10 porphyrins were obtained in quantitative yields by self-assembly of a single bis-zincporphyrin metallacycle (1) with appropriate polytopic N-linkers: the trigonal planar tpt or the cruciform porphyrins 4'-TPyP and 4'-TPhPyP.     

钌-菲罗啉卟啉的合成及与DNA的相互作用

以5-(4-羟基苯基)-10,15,20-三苯基卟啉和钌-菲罗啉衍生物为原料, 合成了3个两亲性钌-菲罗啉卟啉化合物, 并通过核磁共振波谱、红外光谱、紫外-可见光谱、质谱和元素分析等对化合物的结构进行了确证. 采用紫外-可见光谱、 荧光发射光谱和圆二色光谱考察了目标化合物与ct-DNA的相互作用, 研究了它们与DNA的结合模式. 实验结果表明, Por1, Por2和Por3与DNA的结合常数分别为1.46×10⁵, 2.75×10⁵和5.69×10⁵ L/mol. 此外, 在不同DNA浓度下, Por1和Por2与DNA的结合模式为插入模式和外部结合模式共存, Por3与DNA的结合模式主要为自堆积的外部键合和静电作用. 结果表明, 钌-菲罗啉卟啉化合物是新型的光动力治疗试剂.     

胞嘧啶核苷键联卟啉的合成及其与牛血清白蛋白的相互作用

基于卟啉化合物的光敏性和对肿瘤细胞有特殊的亲和力以及核苷类化合物的抗肿瘤及抗癌活性, 设计合成了胞嘧啶核苷卟啉化合物6和8, 其结构由¹H NMR, IR, UV-Vis, MS 和元素分析表征. 同时, 利用荧光光谱考察了上述核苷卟啉与牛血清白蛋白(BSA)的相互作用, 结果表明它们对BSA荧光有较强的静态猝灭作用.     

Fluorescence and absorption spectroscopic studies on the interaction of porphyrins with snake gourd (Trichosanthes anguina) seed lectin

The interaction of several free-base porphyrins and their corresponding copper(II) and zinc(II) derivatives with the galactose-specific lectin from snake gourd (Trichosanthes anguina) seeds has been investigated by absorption and fluorescence spectroscopic techniques. The lectin dimer contains two apparently equivalent binding sites for the porphyrins. Association constants obtained for the interaction of various porphyrins with the lectin are in the range 1.7 x 10(4)-6.2 x 10(5) M(-1), with the metalloporphyrins being seen to have higher affinity for the lectin compared with the free-base analogues. Both positively charged and negatively charged porphyrins bind to snake gourd seed lectin (SGSL) with comparable affinities, suggesting that binding occurs primarily via hydrophobic interactions. Further, binding of porphyrins is found to be largely unaffected by the presence of the sugar ligand, lactose, indicating that the binding sites for the carbohydrate and porphyrin are different. This study thus suggests that the lectin may serve as a receptor for some endogenous non-carbohydrate, hydrophobic ligand in vivo, in addition to the saccharide ligands. It also opens up the possibility of employing the T. anguina lectin in applications such as photodynamic therapy, which involve the use of porphyrins.     

Synthesis of "Porphyrin-linker-Thiol" molecules with diverse linkers for studies of molecular-based information storage

The attachment of redox-active molecules such as porphyrins to an electroactive surface provides an attractive approach for electrically addressable molecular-based information storage. Porphyrins are readily attached to a gold surface via thiol linkers. The rate of electron transfer between the electroactive surface and the porphyrin is one of the key factors that dictates suitability for molecular-based memory storage. This rate depends on the type and length of the linker connecting the thiol unit to the porphyrin. We have developed different routes for the preparation of thiol-derivatized porphyrins with eight different linkers. Two sets of linkers explore the effects of linker length and conjugation, with one set comprising phenylethyne units and one set comprising alkyl units. One electron-deficient linker has four fluorine atoms attached directly to a thiophenyl unit. To facilitate the synthesis of the porphyrins, convenient routes have been developed to a wide range of aldehydes possessing a protected S-acetylthio group. An efficient synthesis of 1-(S-acetylthio)-4-iodobenzene also has been developed. A set of porphyrins, each bearing one S-acetyl-derivatized linker at one meso position and mesityl moieties at the three remaining meso positions, has been synthesized. Altogether seven new aldehydes, eight free base porphyrins and eight zinc porphyrins have been prepared. The zinc porphyrins bearing the different linkers all form self-assembled monolayers (SAMs) on gold via in situ cleavage of the S-acetyl protecting group. The SAM of each porphyrin is electrochemically robust and exhibits two reversible oxidation waves.     

离子液体作高效液相色谱流动相添加剂测定水杨酸

建立了以离子液体作反相高效液相色谱流动相添加剂测定水杨酸的方法.实验以ZORBAX ODS反相色谱柱为分离柱,采用紫外检测方法,研究了检测波长、离子液体烷基链长度、离子液体溶液的浓度以及pH值等对分离和测定的影响.优化的色谱条件为:以体积比60:40的甲醇-3.0 mmol/L1-丁基-3-甲基咪唑四氟硼酸盐溶液(乙酸...     

Study on the interaction of new water-soluble porphyrin with DNA

A porphyrin meso-tetrakis{[4-(1-pyridyl)propoxy]phenyl}porphyrin (TPyPP) and its Ni complex (TPyPP(Ni)) have been synthesized and characterized by 1H NMR, UV-vis spectra. The interaction of two porphyrins with calf thymus-DNA (CT-DNA) has been explored by UV-vis, fluorescence and circular dichroic spectroscopy and viscosity measurements. The results suggest that these porphyrins can bind to DNA by the same binding mode. TPyPP outside binds by self-stack with DNA both at low drug load r (=[porphyrin]/[DNA]) and high drug load. Though TPyPP(Ni) has center metal nickel, binding mode with DNA has little difference compared with TPyPP, dominating out-binding mode with different direction along DNA. The binding constants of the TPyPP and TPyPP(Ni) to DNA were 4.65 x 10(5) M(-1) and 3.2 x 10(5) M(-1), respectively. A colored precipitate was found after time in two porphyrin's viscosity measurement. The reasonable interpretation is the porphyrins with alkyl connected N-position of pyridine can strongly interact with the anionic phosphates of DNA and lead to hydrophobic complex.     

烟酸修饰尾式卟啉的合成及其与人血清白蛋白的相互作用

合成了烟酸分子修饰的自由卟啉o-(niacin)C2O-T(3p-OCH3)PP、p-(niacin)C2O-T(3p-OCH3)PP及锌配合物o-(niacin)C2O-T(3p-OCH3)PPZn、p-(niacin)C2O-T(3p-OCH3)PPZn.经元素分析、紫外-可见光谱、核磁共振氢谱(1HNMR)、红外(IR)光谱等对结构进行了表征,并通过量子化学方法计算了锌卟啉的最低能量构型.实验结果表明:o-(niacin)C2O-T(3p-OCH3)PPZn中侧链烟酸基团处于卟啉环上方,烟酸基团中N原子与卟啉环中Zn2+存在着Zn―N间的分子内配位作用,而p-(niacin)C2O-T(3p-OCH3)PPZn中侧链烟酸基团处于卟啉环较远的位置,一个锌卟啉的中心Zn2+与另一个锌卟啉烟酸中N原子之间存在着Zn―N间的分子间配位作用.同时,为模拟金属卟啉的生物功能,采用荧光光谱滴定法测定了金属锌卟啉与人血清白蛋白相互作用的光谱性质.荧光光谱实验结果显示:金属锌卟啉与人血清白蛋白(HSA)之间发生了较强的静态荧光猝灭作用,反应机理是以氢键或van der Waals力结合反应.按照Stern-Volmer方程、Lineweaver-Burk双倒数方程分析和处理实验数据,得到了反应的猝灭常数、结合常数和热力学参数等.     

Benzylic modifications of meso-alkyl-substituted porphyrins via oxidation with DDQ

The reactions at the benzylic positions of meso-alkyl-substituted porphyrins have been achieved via the reaction with DDQ in the presence of alcohol or water for the first time, and ethenyl porphyrins from methoxylated porphyrins and an acetoxy porphyrin from the hydroxyl porphyrin were prepared.     

Selective Hemin Binding by a Non-G-quadruplex Aptamer with Higher Affinity and Better Peroxidase-like Activity

Previous aptamers for porphyrins and metalloporphyrins were all guanine-rich sequences that can fold in G-quadruplex structures. Due to stacking-based binding, these aptamers can hardly tell different porphyrins apart, and they can also bind other planar molecules, hindering their practical applications. In this work, we used the capture selection method to obtain aptamers for hemin and protoporphyrin IX (PPIX). The hemin aptamer (Hem1) features two highly conserved repeating binding loops, and it cannot form a G-quadruplex, which was supported by its Mg²⁺-dependent but K⁺-independent hemin binding and CD spectroscopy. Isothermal titration calorimetry revealed much higher enthalpy change for the new aptamer, and the best aptamer showed a K_d of 43 nM hemin. Hem1 can also enhance the peroxidase-like activity of hemin. This work demonstrates that aptamers have alternative ways to bind porphyrins allowing selective recognition of different porphyrins.     

Decreased Electron Transfer Rates of Manganese Porphyrins with Conformational Distortion of the Macrocycle

Slow electron transfer to manganese(iii) porphyrins results when the macrocycle deviates from planarity. This was demonstrated by measuring the kinetics of homogeneous electron transfer from a series of semiquinone radical anions to synthetic manganese porphyrins (shown schematically; R¹=H, Cl, F; R²=H, F). Three of the four porphyrins studied have nonplanar macrocycles. These results could have implications for the role of manganese in biological electron transfer processes.     

The interaction of cationic and anionic porphyrins with the bovine serum albumin in borate buffer

The interaction of water-soluble porphyrins with the bovine serum albumin in borate buffer at pH 8.6 has been studied. The localization of porphyrins in the protein globule has been determined. It was established that the native conformation of albumin upon binding with the porphyrins is preserved, however, the anionic porphyrins are exhibit wedging effect on the albumin domains. The binding constants were obtained from fluorescence spectroscopy data.     

Synthesis of mono- and disubstituted porphyrins: A- and 5,10-A2-type systems

General syntheses have been developed for meso-substituted porphyrins with one or two substituents in the 5,10-positions and no beta substituents. 5-Substituted porphyrins with only one meso substituent are easily prepared by an acid-catalyzed condensation of dipyrromethane, pyrrole-2-carbaldehyde, and an appropriate aldehyde using a "[2+1+1]" approach. Similarly, 5,10-disubstituted porphyrins are accessible by simple condensation of unsubstituted tripyrrane with pyrrole and various aldehydes using a "[3+1]" approach. The yields for these reactions are low to moderate and additional formation of either di- or monosubstituted porphyrins due to scrambling of the intermediates is observed. However, the reactions can be performed quite easily and the desired target compounds are easily removed due to large differences in solubility. A complementary and more selective synthesis involves the use of organolithium reagents for S(N)Ar reactions. Reaction of in situ generated porphyrin (porphine) with 1.1-8 equivalents of RLi gave the monosubstituted porphyrins, while reaction with 3-6 equivalents of RLi gave the 5,10-disubstituted porphyrins in yields ranging from 43 to 90 %. These hitherto almost inaccessible compounds complete the series of different homologues of A-, 5,15-A(2)-, 5,10-A(2)-, A(3)-, and A(4)-type porphyrins and allow an investigation of the gradual influence of type, number, and regiochemical arrangement of substituents on the properties of meso-substituted porphyrins. They also present important starting materials for the synthesis of ABCD porphyrins and are potential synthons for supramolecular materials requiring specific substituent orientations.