回顾与展望:酞菁及其应用

本文介绍了酞菁化合物的简史;综述了酞菁化合物薄膜的制备方法。对酞菁化合物在光电导体,能量转换器,非线性光学,发光,气体传感器,变色和有机超晶格结构等方面的应用和存在的问题作了详细描述;并对酞菁化合物的应用前景作了展望     

1,4,8,11,15,18,22,25-octasubstituted phthalocyanines: the contrasting effects of alkyl and alkoxy substituents on molecular self-assembly

The introduction of eight alkoxy or eight alkyl substituents onto the phthalocyanine (Pc) nucleus at the non-peripheral (1,4,8,11,15,18,22,25) positions produces derivatives which are soluble in a variety of organic solvents. However, other physico-chemical properties of the two series differ. Octa-alkyl derivatives, R₈ Pcs, pack as more ordered molecular assemblies in the solid state and show thermotropic liquid crystal behaviour with transition temperatures dependent upon substituent chain length and the central metal atom. In contrast, octa-alkoxy materials, (RO)₈ Pcs, melt directly into the isotropic liquid. The latter can be deposited as Langmuir-Blodgett films whereas the former cannot. Experiments with examples of the two series in which one or two of the chains are functionalized at the terminal positions with a hydrophilic moiety show that these amphiphilic analogues deposit well by the Langmuir-Blodgett method. A number of the films show a high degree of molecular ordering, as judged by X-ray reflectivity methods, transmission infrared, RAIRS and polarized optical spectroscopy. Results indicate that the type of ordering is controlled by the type of substituent and the length of the chain.     

1,4,8,11,15,18,22,25-octasubstituted phthalocyanines: the contrasting effects of alkyl and alkoxy substituents on molecular self-assembly

The introduction of eight alkoxy or eight alkyl substituents onto the phthalocyanine (Pc) nucleus at the non-peripheral (1,4,8,11,15,18,22,25) positions produces derivatives which are soluble in a variety of organic solvents. However, other physico-chemical properties of the two series differ. Octa-alkyl derivatives, R₈ Pcs, pack as more ordered molecular assemblies in the solid state and show thermotropic liquid crystal behaviour with transition temperatures dependent upon substituent chain length and the central metal atom. In contrast, octa-alkoxy materials, (RO)₈ Pcs, melt directly into the isotropic liquid. The latter can be deposited as Langmuir-Blodgett films whereas the former cannot. Experiments with examples of the two series in which one or two of the chains are functionalized at the terminal positions with a hydrophilic moiety show that these amphiphilic analogues deposit well by the Langmuir-Blodgett method. A number of the films show a high degree of molecular ordering, as judged by X-ray reflectivity methods, transmission infrared, RAIRS and polarized optical spectroscopy. Results indicate that the type of ordering is controlled by the type of substituent and the length of the chain.     

基于酞菁光控自组装的超分子三阶非线性光开关材料

酞菁的三阶非线性光学性能不仅取决于其分子结构，而且与酞菁分子在空间的排列密切相关。因此，控制酞菁化合物在空间的排列状态，就有望在超分子的层次控制酞菁的三阶非线性光学性能。我们设计了三类含有光致变色单元修饰的酞菁化合物。利用紫外光和可见交替照射下光致变色单元光异构过程中空间结构和电子结构的改变，实现了对酞菁自组装行为的有效光控。我们用Z-扫描的方法考察了光照前后这些酞菁光控自组装体系三阶非线性光学性能的改变。发现：这些材料不仅开关效应显著，且在“开”和“关”的状态下，都具有大的二阶分子超极化率（〉10^-30esu），在未来光电子和光子技术领域具有潜在的应用价值。     

The effect of aggregation on the nonlinear optical absorption performance of indium and gallium phthalocyanines in a solution and co-polymer host

The nonlinear optical properties (NLO) of Pcs can be modified by substituting different metal atoms into the ring or altering peripheral and axial functionalities. In this study, nonlinear optical absorption properties of tetra-substituted gallium and indium phthalocyanine complexes both in solution and polymeric film have been investigated by open aperture Z-scan measurements with nanosecond pulses at 532 nm. All investigated compounds exhibited reverse saturable absorption for both solution and film experiments. The investigated compounds in the solution showed better nonlinear optical absorption properties than polymeric films. The observed nonlinear optical absorption differences depending on the aggregation are discussed using the ultrafast dynamics and decay processes of excited states found from femtosecond pump-probe spectroscopy with white light continuum experiments.     

Noncovalent complexes of Ih−C80 fullerene with phthalocyanines

The noncovalent interactions of I_h?C₈₀ fullerene with free-base and 3d transition M(II) phthalocyanines (where M = Mn, Fe, Co, Ni, Cu, Zn) were studied at the PBE-D/DNP level of density functional theory. The optimized complex geometries, formation energies and electronic parameters were analyzed and compared to those reported previously for similar dyads with C₆₀. In the complexes with I_h?C₈₀, the central metal atom (as well as one H atom of H₂Pc) is always coordinated to a C_6:6:6 atom of C₈₀ cage, exhibiting only one general interaction pattern. The shortest M^…C_C80 and N^…C_C80 distances are notably longer than in dyads with C_60, and the distortion of Pc macrocycle is less significant. In none of C₈₀-based dyads the formation of new coordination bonds by metal atoms was observed. The bonding strength for Pc–C₈₀ dyads varies approximately to the same degree of 20 kcal/mol as for their Pc–C₆₀ analogues, however negative formation energies for Pc–C₈₀ dyads are on average by 5–6 kcal/mol lower than for their C₆₀ analogues. While in closed-shell Pc–fullerene systems HOMO is usually found totally on Pc molecule, in the case of C₈₀-based dyads only a minor HOMO fraction can be detected for some dyads on Pc, with the major one always distributed over fullerene cage. As a result, the calculated HOMO-LUMO gap energies turn to be very low, around 0.1 eV. Analysis of spin density plots revealed that H₂Pc+C₈₀, NiPc+C₈₀ and ZnPc+C₈₀ dyads behave as closed-shell systems, like similar noncovalent complexes of Pcs with C₆₀.     

Electrical and optical properties of phthalocyanine films

Thin films of various phthalocyanines (Pcs) were sublimed onto quartz glass in ultrahigh vacuum. The electrical and optical properties were studied without breaking the ultrahigh vacuum. The dyes were purified by repeated sublimation in vacuum.The conductivity varied with pretreatment (modification) and temperature. Exposure to oxygen, iodine and bromine increased the p-type conductivity by orders of magnitude and lithium doping caused n-type conductivity. Heavy exposure to halogens caused not only broadening of the optical absorption band but also bleaching. Annealing in vacuum removed the electrical and optical effects of doping nearly completely.Field effect studies were used to identify p- and n-type conductivity, to determine the drift mobility and to estimate the trap densities. The field effect and the photoconductivity of p- and n-type films increased by several orders of magnitude with the dark conductivity, i.e. with doping. This correlation is attributed either to traps with a continuous distribution in energy or to trapping by at least two discrete defect levels crossing the Fermi level within the surface-induced accumulation layer. Possible consequences for the sensitivity of semiconductor gas sensors are discussed.     

Continuous analogue to iterative optimization for PDE-constrained inverse problems

The parameters of many physical processes are unknown and have to be inferred from experimental data. The corresponding parameter estimation problem is often solved using iterative methods such as steepest descent methods combined with trust regions. For a few problem classes also continuous analogues of iterative methods are available. In this work, we expand the application of continuous analogues to function spaces and consider PDE (partial differential equation)-constrained optimization problems. We derive a class of continuous analogues, here coupled ODE (ordinary differential equation)–PDE models, and prove their convergence to the optimum under mild assumptions. We establish sufficient bounds for local stability and convergence for the tuning parameter of this class of continuous analogues, the retraction parameter. To evaluate the continuous analogues, we study the parameter estimation for a model of gradient formation in biological tissues. We observe good convergence properties, indicating that the continuous analogues are an interesting alternative to state-of-the-art iterative optimization methods.     

Polymer-based nanoparticles for the delivery of nucleoside analogues

Nucleoside analogues, together with nucleobases and nucleotide analogues, are commonly used in the treatment of cancer and viral infections. In both cases, they act as antimetabolite agents and interfere with the synthesis of cellular or viral nucleic acids. However, the need of high doses due to the rapid elimination of these compounds, to their poor activation, and/or to their non-specific distribution, often leads to side effects and resistances. The present paper aims to review the different types of polymer nanoparticles which have been designed as drug delivery devices to address these issues. Thus, poly(alkylcyanoacrylate) nanoparticles have been demonstrated as potential carriers for antiviral nucleoside analogues, especially for anti-HIV agents, regarding both intravenous and oral routes. Nanoparticles based on polyesters such as poly(lactic acid) and poly(lactide-co-glycolide) have been used as nanocarriers for nucleosides analogues too, and especially for their ocular delivery. Albumin has shown interesting properties in the design of nanoparticles for the same application, but also for the oral administration of anticancer analogues. Finally, new hydrophilic nanoparticles consisting of cross-linked polymer network ('Nanogels') open the perspective to deliver nucleoside analogues within their active triphosphate form.     

Testing the hypothesis that amphiphilic antineoplastic lipid analogues act through reduction of membrane curvature elastic stress

The alkyllysophospholipid (ALP) analogues Mitelfosine and Edelfosine are anticancer drugs whose mode of action is still the subject of debate. It is agreed that the primary interaction of these compounds is with cellular membranes. Furthermore, the membrane-associated protein CTP: phosphocholine cytidylyltransferase (CCT) has been proposed as the critical target. We present the evaluation of our hypothesis that ALP analogues disrupt membrane curvature elastic stress and inhibit membrane-associated protein activity (e.g. CCT), ultimately resulting in apoptosis. This hypothesis was tested by evaluating structure–activity relationships of ALPs from the literature. In addition we characterized the lipid typology, cytotoxicity and critical micelle concentration of novel ALP analogues that we synthesized. Overall we find the literature data and our experimental data provide excellent support for the hypothesis, which predicts that the most potent ALP analogues will be type I lipids.     

Predictability,uncertainty, and hyperbolicity in the ocean

Lagrangian predictability of an ocean flow is studied using ideas from dynamical systems theory. Finite-time analogues of invariant manifolds and attractors are utilized to parse the flow field into regions with distinct advective fates or destinations. These analogues take the form of inflowing and outflowing material curves emanating from hyperbolic trajectories. Applications are made to the Gulf of Mexico using a high resolution, data assimilating, primitive equation hydrodynamic model.     

Signaling aptamers created using fluorescent nucleotide analogues

A new approach to creating fluorescent signaling aptamers using fluorescent nucleotide analogues is presented. The fluorescence quantum yield of nucleotide analogues such as 2-aminopurine strongly depends on base stacking interactions when incorporated into double or single stranded DNA. This property is used to generate a binding-specific fluorescence signal. Aptamers for human alpha-thrombin, immunoglobulin E, and platelet-derived growth factor B were modified with fluorescent nucleotide analogues in positions that undergo conformational changes. The resulting signaling aptamers show a specific, binding-induced increase in the fluorescence signal of up to 30-fold. Conformation-changing positions in these aptamers were identified by screening a set of modified aptamer sequences that each included a fluorescent nucleotide analogue at a different position. The positions for these modifications were estimated by modeling the aptamer secondary structure. It is likely that this approach to producing fluorescent signaling aptamers is of general use for protein-binding aptamers because of their "induced fit" binding mechanism.     

Isotope and affinity tags in photoreactive substance P analogues to identify the covalent linkage within the NK-1 receptor by MALDI-TOF analysis

Photoreactive analogues of substance P (biotin sulfone-spacer (amino pentanoic or Gly(3))-Arg-Pro-Lys-Pro-(pBzl)Phe-Gln-Phe-Phe-Gly-Leu-Met(O(2))NH(2)) with or without isotope (deuterium) labeling have been synthesized. Deuteriums were present on (d)-biotin or epibiotin sulfone (D(3)), on the Gly(3) spacer linker (D(6)), or on the Gly in position 9 of SP (D(2)). Therefore, peptide analogues could be either unlabeled or tri-, penta-, or hexadeuterated. Results obtained with the use of these peptide analogues show that (d)-biotin sulfone and epibiotin sulfone are not recognized with the same affinity by streptavidin, with (d)-biotin sulfone displaying better affinity for the protein. Photolabeling of the human NK-1 receptor with a 1:1 molar ratio of nondeuterated and deuterated photoreactive substance P (SP) analogues in position 5, followed by combined digestions, purification, and MALDI-TOF mass spectrometry analysis, made the identification of the domain of the receptor covalently linked by the photoreactive SP analogue easier. Indeed, doublets in mass spectra were specific for the covalent complex whereas single peaks could be attributed to contaminating species. This method is particularly suitable when minute amounts of complex have to be analyzed, as in the case of highly hydrophobic G-protein coupled receptors.     

Adsorption on molecularly imprinted polymers of structural analogues of a template. Single-component adsorption isotherm data

The equilibrium adsorption isotherms on two otherwise identical polymers, one imprinted with Fmoc-L-tryptophan (Fmoc-L-Trp) (MIP), the other nonimprinted (NIP), of compounds that are structural analogues of the template were acquired by frontal analysis (FA) in an acetonitrile/acetic acid (99/1 v/v) mobile phase, over a wide concentration range (from 0.005 to 50 mM). These analogues were Fmoc-L-tyrosine, Fmoc-L-serine, Fmoc-L-phenyalanine, Fmoc-glycine (Fmoc-Gly), Fmoc-L-tryptophan pentafluorophenyl ester (Fmoc-L-Trp(OPfp)), and their antipodes. These substrates have different numbers of functional groups able to interact with the 4-vinylpyridine groups of the polymer. For a given number of the functional groups, these substrates have different hydrophobicities of their side groups (as indicated by their partition coefficients (log P(ow)) in the octanol-water system (e.g., from 4.74 for Fmoc-Trp to 2.53 for Fmoc-Gly)). Statistical results from the fitting of the FA data to Langmuirian isotherm models, the calculation of the affinity energy distribution, and the comparison of calculated and experimental band profiles show that all these sets of FA data are best accounted for by a tri-Langmuir isotherm model, except for the data of Fmoc-L-Trp(OPfp) that are best modeled by a simple Langmuir isotherm. So, all compounds but Fmoc-L-Trp(OPfp) find three different types of adsorption sites on both the MIP and the NIP. The properties of these different types of sites were studied systematically. The results show that the affinity of the structural analogues for the NIP is controlled mostly by the number of the functional groups on the substrates and somewhat by the hydrophobicity of their side groups. These two factors control also the MIP affinity toward the enantiomers of the structural analogues that have a stereochemistry different from that of the template. In contrast, the affinity of the highest affinity sites of the MIP toward the enantiomers of these structural analogues that have the same stereochemistry as the template is highest for the imprinted molecule (Fmoc-L-Trp). The separation of the template from the substrates with the same stereochemistry is influenced by the number of the functional groups on the substrates that can interact with the highest affinity sites on the MIP. The separation of the enantiomers of the analogues of the substrates was also achieved on the MIP, and these enantiomeric separations are influenced by the hydrophobicity of the substrates.     

Desorption chemical ionization, thermospray, and fast atom bombardment mass spectrometry of dihydropyridine in equilibrium with pyridinium salt-type redox systems

Trigonellyl-substituted (pyridinium salt type) compounds decompose during sample introduction using desorption chemical ionization (DCI) and thermospray (TSP) ionization. Thermal dequaternization is the main degradation process in DCI, while hydrolytically sensitive bonds are subject to cleavage in the TSP source, and dequaternization and reduction to the dihydropyridine analogues are also observed. Fast atom bombardment (FAB) is the suggested method of ionization because of its ability to provide an intense intact cation. The neutral dihydropyridine analogues can be effectively ionized by DCI and TSP. These methods are recommended, because bombardment-induced oxidation produces artifacts and shows a matrix effect in positive FAB.     

Effects of oxidizing gases on semiconductivity and thermal stability of phthalocyanine thin films

The effects of oxidizing gases (O₂ and NO₂) on the p-type semiconductivity of the phthalocyanines H₂Pc, PbPc, ZnPc, CuPc, AlPcCl, AlPc-O-AlPc and (AlPc) _n films treated in nitrogen at 350 ° C have been examined. The conductance increased in the presence of oxidizing gases. Reversible effects of oxidizing gases on the conductance were observed for PbPc, CuPc and ZnPc, all of which are thermally and/or chemically less stable than the other Pcs. For the latter, the conductance in nitrogen increased permanently after exposure to NO₂. The reversibility of the former may be related to the thermal and chemical stability of neutral and/or oxidized phthalocyanines. The conductivity is described byG =G ₀ exp (E/kT) The activation energy,E, decreased in the presence of oxidizing gases. The pre-exponential factor,G ₀, was lowered by the introduction of NO₂ especially for PbPc, CuPc and ZnPc. It seems that the adsorption of NO₂ is limited to the surface of fine crystals and the increase in the conductance caused by exposure to NO₂ is strongly influenced by the crystallinity of phthalocyanine.     

Squalenoyl nanomedicines as potential therapeutics

Nucleoside analogues display significant anticancer or antiviral activity by interfering with DNA synthesis. However, there are some serious restrictions to their use, including their rapid metabolism and the induction of resistance. We have discovered that the linkage of nucleoside analogues to squalene leads to amphiphilic molecules that self-organize in water as nanoassemblies of 100-300 nm, irrespective of the nucleoside analogue used. The squalenoyl gemcitabine exhibited superior anticancer activity in vitro in human cancer cells and gemcitabine-resistant murine leukemia cells, and in vivo in experimental leukemia both after intravenous and oral administration. The squalenoylation of other antiretroviral nucleosides also led to more potent drugs when tested in primary cultures of HIV-infected lymphocytes. Thus, the squalenoylation is an original technology platform for generating more potent anticancer and antiviral nanomedicines.     

Indium(III) and Gallium(III) phthalocyanines-based nanohybrid materials for optical limiting

Linear and nonlinear optical properties of a phthalocyanine (Pc)-based nanohybrid material PCIGS [Cu₂(tBu₄PcGa)(tBu₄PcIn)S₂TPP₂] are described. The overall aggregation of phthalocyanines in poly(methylmethacrylate) (PMMA) films was evident, which is indicated by the broadening of linear spectra in the Q-band region and the shift of wavelength. Upon excitation with nanosecond laser pulse at 355 nm, the transient absorption band appeared at about 500 nm is attributed to the triplet–triplet absorption of the Pcs. For PCIGS and its starting materials tBu₄PcGaCl and tBu₄PcInCl, all Z-scans exhibit a decrease in transmittance about the focus typical of an induced positive nonlinear absorption of incident light. The absorption mechanism is due to population of excited states through a multi-step nonlinear absorption. When these Pc compounds were embedded into a commercially available polymer PMMA, all the Pc/PMMA composites display much larger nonlinear absorption coefficient and lower saturable fluence for optical limiting when compared to the same Pc molecules in solution. However, in contrast to tBu₄PcGaCl and tBu₄PcInCl, PCIGS displayed decreased optical limiting response, possibly due to competing electron accepting processes in the In and Ga metals, and the highly ordered structure of the PCIGS complex itself.     

Percutaneous Absorption of Capsaicin and Its Derivatives

Nonivamide (NVA), sodium nonivamide acetate (SNA) and sodium nonivamide propionate (SNP) are analogues of Capsaicin (CAP). The structure and pungent property of NVA are similar to CAP. The solubilities of SNA in different pH value buffer solution were higher than that of NVA and CAP. For the NVA and SNA, the n-octanol/buffer partition coefficients decreased with increasing pH value. The fluxes of CAP and its analogues were determined using excised rat skin and the effect of pH was also investigated. The flux of NVA and SNA mixture was higher than individually NVA or SNA, and the ratio of 70:30 was a better choice. Sodium lauryl sulfate (SLS), an anionic surfactant, had significant effect on SNA skin permeation.     

Recovery of Characteristics of Non-Stationary Dynamic Systems from Three Test Signals

Measurement Techniques - Non-stationary continuous and discrete dynamical systems are modeled, respectively, by Volterra integral equations of the first kind and their discrete analogues....