不同类型卟啉自组装膜的制备及表征

制备了不同类型的巯基卟啉自组装膜,借助多种表征技术（紫外可见光谱、电化学和X射线光电子能谱）研究了不同类型卟啉自组装膜的结构特点;研究结果表明,卟啉分子中巯基取代基数目的不同（-[SH]n-,n=1,4）,导致了卟啉环在自组装膜表面的构型不同,从而表现出不同巯基卟啉自组装膜性能的差异。 在此基础上,提出了不同巯基卟啉自组装膜的结构模型。     

表面增强喇曼光谱检测卟啉单分子膜

利用轴向配位作用将5,10,15－20－四苯基钴（Ⅱ）卟啉（CoTPP)固定在4－巯基吡啶自组装膜表面上,形成CoTPP单分子膜,通过组装金纳米粒子的方法,成功地获得了膜中CoTPP分子的喇曼光谱。研究结果表明,CoTPP分子是通过钴原子与氮原子之间的配位作用与巯基吡啶分子结合的,且其分子平面与基底表面近似平行。     

巯基卟啉自组装膜的制备及应用研究进展

详细介绍了巯基卟啉自组装膜的几种制备方法,评述了不同制备方法的优缺点;对卟啉自组装膜在电荷转移、分子氧电催化、分子光电器件等领域的研究进展进行了评述,引用文献54篇。     

羧基卟啉锌-铜超分子体系的荧光增强特性

通过稳态荧光光谱滴定和紫外-可见光谱考察了5-(对羧基苯基-甲酰氨基)苯基10，15，20-三苯基卟啉(p-CPTPP)锌(Ⅱ)、铜(Ⅱ)配合物体系通过氢键的超分子自组装行为。在荧光光谱滴定中，当Cu(p-CPTPP)浓度在一定范围内时，随着Cu(p-CPTPP)浓度增大，Zn(p-CPTPP)-Cu(p-CPTPP)体系荧光强度逐渐增大并稍有红移。根据荧光光谱滴定数据计算了超分子的结合常数，由小波变换方法分解得到的超分子电荷分离态荧光光谱解释了体系荧光增强现象。     

Meso-四对甲氧基苯基卟啉荧光被Hg（Ⅱ）猝灭后荧光恢复的研究

通过 meso-四对甲氧基卟啉荧光被Hg2 猝灭后荧光恢复这一现象证明了卟啉的自组装行为.meso-四对甲氧基苯基卟啉丙酮溶液荧光加入Hg2 后猝灭,少量水的引入使卟啉通过氢键发生自组装,这时荧光恢复.Hg2 加入后立即发生猝灭,但是恢复却是比较缓慢的,连续加入Hg2 ,荧光呈周期性的猝灭和恢复.并且通过荧光光谱和紫外光谱论证了这一现象.     

铜电极表面硅烷膜的自组装及其性能研究

应用自组装技术在铜电极表面上制备3巯基丙基三甲氧基硅烷自组装膜.红外光谱研究该自组装膜结构,电化学方法考察3-巯基丙基三甲氧基硅烷膜在5%NaCl溶液中对铜电极的缓蚀性能.结果表明,于不同浓度的3-巯基丙基三甲氧基硅烷乙醇溶液中自组装的硅烷膜表现出较好的抗腐蚀性.     

卟啉纳米材料制备及在可视化传感器中的应用

在水/油体系中,利用表面活性剂辅助自组装制备出5,10,15,20-四苯基卟啉锌(ZnTPP)和5,10,15,20-四苯基卟啉钴(CoTPP)纳米材料,改变陈化时间制备多种形貌卟啉纳米材料,如纳米球、纳米棒和纳米片等。利用紫外-可见光谱和荧光光谱分析两种卟啉纳米材料的光学性质,ZnTPP纳米材料的荧光强度是其单体的4.5倍,具有良好光敏性。基于两种卟啉纳米材料构建可视化阵列芯片对挥发性气体己醛检测,卟啉纳米的响应度是它们单体的2倍。     

疏基烷氧基喹啉化合物的合成

自组装单分子膜 ( Self- Assembled Monolayer,SAM)由于其致密和高度有序性在分子器件、修饰电极、纳米电子学以及仿生科学等领域有着广泛的应用前景。可用于自组装的材料有脂肪醇、有机硅烷和烷基硫醇类衍生物 [1]。自组装膜的研究大多数集中于巯基化合物在金表面共价吸附形成的单分子膜 ,为了得到具有不同功能的自组装膜就需要合成带有不同功能基团的巯基化合物。广泛使用的是具有X( CH2 ) n SH结构的巯基化合物 [2 ] ( X为所感兴趣的官能团 )。文献 [3] 报道了含酰胺键、偶氮苯基的 SAM材料的合成。巯基烷氧基喹啉化合物是一类新型…     

卟啉多枝分子合成与分子内能量转移、双光子吸收性能研究

以三苯胺或硝基苯为端基, 合成了三个卟啉多枝分子: 5-(4-硝基苯甲酰氧基)苯基-10,15,20-三-(4-溴苯基)卟啉(TPP-NO₂)、5-(4-硝基苯甲酰氧基)苯基-10,15,20-三-(4-二苯胺基-1-苯乙烯基)苯基卟啉(TPP-X₃)和5,10,15,20-四-(4-二苯胺基-1-苯乙烯基)苯基卟啉(TPP-X₄), 进行了红外光谱、核磁共振光谱和质谱表征. 比较研究了分子“枝”、“核”不同键合方式与不同对称结构对分子的线性光谱、非线性光谱以及分子内能量转移行为的影响. 在钛宝石激光器(800 nm)和Nd∶YAG倍频光(532 nm)泵浦下, 样品溶液均发出卟啉环特有的红色荧光——前者系双光子吸收机制“上转换”荧光, 后者则为双光子吸收与分子内能量转移机制“下转换”荧光. 飞秒Z-scan技术测得样品双光子吸收截面最大可达130 GM, 与四苯基卟啉(TPP)同等测试条件下的双光子吸收截面相比增大了两个数量级.     

卟啉-噁二唑二元体系光诱导能量及电子传递研究

以5-对氨基苯基-10,15,20-三苯基卟啉及2-苯基-5-(对氨基苯基)-1,3,4-噁二唑为原料合成了系列卟啉-噁二唑二元化合物, 其结构通过¹H NMR, ESI-MS, IR, UV-Vis确定. 对合成化合物进行光谱性能测定, 结果表明, 在卟啉与噁二唑混合体系中, 存在着卟啉激发态分子向噁二唑基态分子的分子间电子传递过程, 导致卟啉激发态的荧光猝灭; 在卟啉-噁二唑二元体系中, 315 nm激发下发生了由激发态噁二唑基团至卟啉基团的能量传递, 导致噁二唑基团荧光猝灭, 卟啉基团荧光增强. 420 nm激发下不存在分子内卟啉基团向噁二唑基团的电子回传竞争; 电化学性能测定进一步表明从噁二唑基团向卟啉基团的电子传递是可能的. 因此卟啉-噁二唑二元化合物可能作为一种模型, 模拟光合作用中电子给体至叶绿素之间的电子传递过程.     

Characterization of self-assembled monolayers of porphyrins bearing multiple-thiol and photoelectric response

Self-assembled monolayers(SAMs) of thiol-derivatized porphyrin molecules on Au substrate have attracted extensively interest for use in sensing,optoelectronic devices and molecular electronics.In this paper,tetra-[p-(3-mercaptopropyloxy)-phenyl]porphyrin was synthesized and self-assembled with thiol on Au substrate for porphyrin SAMs(PPS 4).The electrochemical results demonstrated that PPS 4 could form excellent SAMs on gold surface.Self-assembled nanojunctions of PPS 4 were fabricated by using gold nanogap electrodes(gap width:ca.100 nm).With the light on/off,the nanojunctions showed current high/low as nanometer scaled photo switch.     

Structure and photophysical properties of porphyrin-modified metal nanoclusters with different chain lengths

Three-dimensional porphyrin-monolayer-protected gold clusters with different chain lengths (MPCs) have been prepared to examine the structure and photophysical properties, in comparison with self-assembled monolayers (SAMs) of the porphyrins on a flat gold surface. The three-dimensional porphyrin MPCs exhibit electrochemical and photophysical properties that are much closer to those of a porphyrin reference compound in solution than those of two-dimensional porphyrin SAMs on the flat gold surface. The three-dimensional architectures of porphyrin MPCs with large surface area have improved the light-harvesting efficiency relative to the corresponding porphyrin SAM on the two-dimensional flat gold surface. Time-resolved single photon counting fluorescence and transient absorption spectroscopic studies have demonstrated that undesirable quenching of the porphyrin excited singlet state via energy transfer to the gold surface of the three-dimensional MPCs is much suppressed, as compared to the quenching of the porphyrin SAMs on the two-dimensional flat gold surface. Both the quenching rate constants of the porphyrin excited singlet state by the surfaces of bulk gold and gold nanoclusters reveal weak chain length dependence of the energy transfer quenching.     

Scanning tunneling microscopy observation of self-assembled monolayers of strapped porphyrins

In this paper, we reveal that the free-base and zinc strapped porphyrins possessing long alkyl chains, C 24OPP-HQ and Zn(C 24OPP-HQ), respectively, can be arranged on surfaces. We used scanning tunneling microscopy (STM) to observe alkyl-chain-assisted self-assembled monolayers (SAMs) of these strapped porphyrins at the solid-liquid interface. STM images revealed that the strapped benzene moiety was detectable on the porphyrin core: that is, the strapped porphyrins could be differentiated from nonstrapped analogues. We compared the population of the nonstrapped porphyrin (C 24OPP) and either of the strapped porphyrins C 24OPP-HQ or Zn(C 24OPP-HQ) in the mixed SAMs. We then confirmed that Zn(C 24OPP-HQ) is more favorably incorporated in the mixed SAMs than C 24OPP-HQ. From (1)H NMR spectroscopic and X-ray crystallographic analyses, we concluded that the factors increasing the population of Zn(C 24OPP-HQ) in the mixed SAMs are the enhanced rigidity of the porphyrin core by the zinc coordination and the flat structure of the porphyrin moiety in the saddle conformation. This study demonstrates that strapped porphyrins possessing long alkyl chains are available to arrange the functional modules on the surface via chemical modification on the strapped moiety.     

Non-covalent immobilization of C60 on gold surfaces by SAMs of porphyrin derivatives

Three porphyrin derivatives, one containing thioctic ester groups (3) and the other two with thioether chains (4 and 5), were synthesized. The cyclic voltammograms of the porphyrin compounds exhibit two reversible reduction processes and one reversible oxidation. Stable self-assembled monolayers (SAMs) of the porphyrin compounds were formed on gold surfaces. Non-covalent immobilization of C₆₀ was accomplished upon incubation of some of the porphyrin SAMs in solutions of C₆₀.     

Photovoltaic properties of self-assembled monolayers of porphyrins and porphyrin-fullerene dyads on ITO and gold surfaces

A systematic series of ITO electrodes modified chemically with self-assembled monolayers (SAMs) of porphyrins and porphyrin-fullerene dyads have been designed to provide valuable insight into the development of artificial photosynthetic devices. First the ITO and gold electrodes modified chemically with SAMs of porphyrins with a spacer of the same number of atoms were prepared to compare the effects of energy transfer (EN) quenching of the porphyrin excited singlet states by the two electrodes. Less EN quenching was observed on the ITO electrode as compared to the EN quenching on the corresponding gold electrode, leading to remarkable enhancement of the photocurrent generation (ca. 280 times) in the porphyrin SAMs on the ITO electrode in the presence of the triethanolamine (TEA) used as a sacrificial electron donor. The porphyrin (H(2)P) was then linked with C(60) which can act as an electron acceptor to construct H(2)P-C(60) SAMs on the ITO surface in the presence of hexyl viologen (HV(2+)) used as an electron carrier in a three electrode system, denoted as ITO/H(2)P-C(60)/HV(2+)/Pt. The quantum yield of the photocurrent generation of the ITO/H(2)P-C(60)/HV(2+)/Pt system (6.4%) is 30 times larger than that of the corresponding system without C(60): ITO/H(2)P-ref/HV(2+)/Pt (0.21%). Such enhancement of photocurrent generation in the porphyrin-fullerene dyad system is ascribed to an efficient photoinduced ET from the porphyrin singlet excited state to the C(60) moiety as indicated by the fluorescence lifetime measurements and also by time-resolved transient absorption studies on the ITO systems. The surface structures of H(2)P and H(2)P-C(60) SAMs on ITO (H(2)P/ITO and H(2)P-C(60)/ITO) have been observed successfully in molecular resolution with atomic force microscopy for the first time.     

卟啉类自组装膜在电分析化学中的应用

评述了卟啉及其金属配合物自组装膜在电分析化学领域的应用研究进展,并简要介绍了卟啉的结构及其金属配合物的特点。对卟啉类自组装膜在电分析化学领域内的应用作了展望。     

Diverse redox-active molecules bearing identical thiol-terminated tripodal tethers for studies of molecular information storage

To examine the effects of molecular structure on charge storage in self-assembled monolayers (SAMs), a family of redox-active molecules has been prepared wherein each molecule bears a tether composed of a tripodal linker with three protected thiol groups for surface attachment. The redox-active molecules include ferrocene, zinc porphyrin, ferrocene-zinc porphyrin, magnesium phthalocyanine, and triple-decker lanthanide sandwich coordination compounds. The tripodal tether is based on a tris[4-(S-acetylthiomethyl)phenyl]-derivatized methane. Each redox-active unit is linked to the methane vertex by a 4,4'-diphenylethyne unit. The electrochemical characteristics of each compound were examined in solution and in SAMs on Au. Redox-kinetic measurements were also performed on the SAMs (with the exception of the magnesium phthalocyanine) to probe (1) the rate of electron transfer in the presence of an applied potential and (2) the rate of charge dissipation after the applied potential is disconnected. The electrochemical studies of the SAMs indicate that the tripodal tether provides a more robust anchor to the Au surface than does a tether with a single site of attachment. However, the electron-transfer and charge-dissipation characteristics of the two tethers are generally similar. These results suggest that the tripodal tether offers superior stability characteristics without sacrificing electrochemical performance.     

Characterization of self-assembled monolayers of porphyrins bearing multiple thiol-derivatized rigid-rod tethers

A series of multithiol-functionalized zinc porphyrins has been prepared and characterized as self-assembled monolayers (SAMs) on Au. The molecules, designated ZnPS(n) (n = 1-4), contain from one to four [(S-acetylthio)methyl]phenylethynylphenyl groups appended to the meso-position of the porphyrin; the other meso-substituents are phenyl groups. For the dithiol-functionalized molecules, both the cis- and the trans-appended structures were examined. The ZnPS(n) SAMs were investigated using X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, and various electrochemical methods. The studies reveal the following characteristics of the ZnPS(n) SAMs. (1) The ZnPS(n) molecules bind to the Au surface via a single thiol regardless of the number of thiol appendages that are available per molecular unit. (2) The porphyrins in the ZnPS(3) and ZnPS(4) SAMs bind to the surface in a more upright orientation than the porphyrins in the ZnPS(1), cis-ZnPS(2), and trans-ZnPS(2) SAMs. The porphyrins in the ZnPS(3) and ZnPS(4) SAMs are also more densely packed than those in the cis-ZnPS(2) and trans-ZnPS(2) SAMs. The packing density of the ZnPS(3) and ZnPS(4) SAMs is similar to that of the ZnPS(1) SAMs, despite the larger size of the molecules in the former SAMs. (3) The thermodynamics and kinetics of electron transfer are generally similar for all of the ZnPS(n) SAMs. The general similarities in the electron-transfer characteristics for all of the SAMs are attributed to the similar binding motif.     

Electrochemical characterization of self-assembled thiol-porphyrin monolayers on gold electrodes by SECM.

Herein, the scanning electrochemical microscopy (SECM) approach is applied to study the formation of thiol-porphyrin self-assembled monolayer (SAMs). Using cyclic voltammetry (CV), the formation process is characterized adopting different probe molecules. The observed phenomena indicate that the formation process is affected by solution properties and the molecular structure of the probe molecules. In K(3)Fe(CN)(6) , the SAMs show a strong electron-transfer (ET) blocking effect on a pure porphyrin-modified electrode. However, addition of metal ions to the porphyrin molecules leads to ET. A consistent tendency is observed throughout the modification process using CV and SECM methods. Furthermore, k(eff) values, the apparent heterogeneous rate constants, obtained for different modification periods affirm the validity of these results. SECM images are used to collect surface information in the course of the modification process when the substrate potential is 0.5 V versus Ag/AgCl. The effect of the substrate potential indicates that the oxidation of the porphyrin molecules is supported by more positive potentials because of the similar bimolecular reaction of the porphyrin ring with positive charge and the probe molecules with negative charge.