Jun 2010, Volume 5 Issue 2
    

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  • Research articles
    The research front on molecular functional switches
    He TIAN,
    2010, 5(2): 113-114. https://doi.org/10.1007/s11458-010-0100-1
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  • Research articles
    High effective sensors based on photonic crystals
    Mingzhu LI, Yanlin SONG,
    2010, 5(2): 115-122. https://doi.org/10.1007/s11458-010-0104-x
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    Photonic crystals have been extensively studied as high effective sensors for environmental monitoring and chemical and biological detections. This paper reviews recent achievements on photonic crystal sensors. Especially, the band gap responsiveness and the ability in amplifying spontaneous emission are demonstrated in the reported photonic crystal monitors/sensors. They are of great importance for optical monitors/sensors visualized by the naked eye and sensors based on fluorescence applications. The photonic crystal sensors are promising for low-cost and high effective sensors and detection methods, although challenges still exist in practical applications.
  • Research articles
    Fluorescent molecular probes for the detection of chemical warfare agents and their mimics
    Yanchun BAI, Chao ZHANG, Chunhu XU, Chunhua YAN,
    2010, 5(2): 123-133. https://doi.org/10.1007/s11458-010-0107-7
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    Owing to their direct toxic effects on human beings, animals, and plants, chemical warfare agents (CWAs) and their mimics have become widespread in chemical warfare and agriculture. The considerable concerns about their entry into biological systems and the residues in environment stimulate the development of rapid and sensitive methods for the detection and analysis of this family of compounds. In the progress of sensitive, selective, and fast responsive detection, fluorescent molecular probes have been widely used in the detection of CWAs in recent years. Here the recent reports on the design of fluorescent molecular probes and their advantages in the detection of CWAs were reviewed. Furthermore, the extensive interests accelerate the development of novel fluorescent molecular probes and detection techniques in this field.
  • Research articles
    Chromophore-functionalized dendrimers for sensing applications
    Jing YAN, Jian PEI,
    2010, 5(2): 134-149. https://doi.org/10.1007/s11458-010-0116-6
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    Chromophore-functionalized dendrimer sensors represent a new class of highly sensitive sensing materials. Here we review various strategies regarding dendrimer sensors, with specific attention being paid to how to achieve signal amplification using dendrimers’ unique geometric features.
  • Research articles
    Structure-property relationships of organic dyes with D-π-A structure in dye-sensitized solar cells
    Zhong-Sheng WANG, Fang LIU,
    2010, 5(2): 150-161. https://doi.org/10.1007/s11458-010-0113-9
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    Organic dyes with a D-π-A structure have drawn increasing attention as sensitizers in dye-sensitized solar cells (DSSCs), due to their rich photophysical properties, easy molecular tailoring, and low-cost production. This review mainly focuses on the relationship between dye structure and photovoltaic properties for organic dyes containing cyanoacrylic acid as both an anchor and an acceptor. This review also introduces different donors and π-conjugation units as building blocks for sensitizer synthesis.
  • Research articles
    A novel fluorescence enhancing F - probe based on intermolecular energy transfer
    Quanguo WANG, Yubin DING, Weihong ZHU, Yongshu XIE,
    2010, 5(2): 162-165. https://doi.org/10.1007/s11458-010-0105-9
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    A supramolecular fluorescent sensor of F− based on intermolecular energy transfer is described. The maximum absorption wavelength of a pyrrolic compound 1 is 472 nm, which is coincident with the emission wavelength of a dipyridylamine-anthracene compound 2. In the CH2Cl2 solution of 1 and 2, the fluorescence of 2 was quenched because of the presence of intermolecular energy transfer from 2 to 1. When F− was added to this solution, the absorption maximum wavelength of 1 shifted from 472 to 594 nm due to a deprotonation process. Simultaneously, the fluorescence of 2 was recovered because of the interruption of the intermolecular energy transfer. Based on these observations, the combination of 1 and 2 can be regarded as a novel supramolecular fluorescence enhancing F− probe.
  • Research articles
    A conjugated polymer - Gd (III) complex as pH sensitive contrast agent in magnetic resonance imaging
    Qingling XU, Libing LIU, Minghui YU, Qiong YANG, Shu WANG, Litao ZHU,
    2010, 5(2): 166-170. https://doi.org/10.1007/s11458-010-0108-6
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    A novel pH-responsive contrast agent (PFP-aa/Gd) for magnetic resonance imaging (MRI) was prepared by binding Gd(III) to a water-soluble conjugated polyfluorene with pendant carboxylate and amine moieties. The PFP-aa is a good chelator for Gd3+ and the PFP-aa/Gd complex has good stability. As the pH changes from 10.0 to 4.0, both the carboxylate and amine are protonated, thus PFP-aa exhibits positive charges and forms tight aggregation, which reduces molecular tumbling and accelerates the exchange of bound water leading to the increase of relaxivity R1. More importantly, the R1 increases by about eight fold as the pH changes from 8.0 to 6.0, which makes PFP-aa/Gd suitable as a potential marker of the pH below physiological level. In comparison to other contrast agents, the unique sensitivity of the water relaxivity of PFP-aa/Gd indicates that this complex could be used in MRI experiments to monitor physiological pH change.
  • Research articles
    Photo-induced electron transfer study of rhenium(I) bipyridyl complexes with covalently linked phenothiazine donor through different bridge
    Shiguo SUN, Lei SHI, Jiangli FAN, Xiaojun PENG, Fengyu LIU,
    2010, 5(2): 171-177. https://doi.org/10.1007/s11458-010-0111-y
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    A novel rhenium(I) bipyridyl complex 1a, [(4,4’-di-COOEt-bpy)Re(CO)3(py-NHCO-PTZ)PF6] and a model 1b, [(4,4’-di-COOEt-bpy)Re(CO)3(py-PTZ)PF6] (bpy is 2, 2’-bipyridine, py-NHCO-PTZ is phenothiazine-(10-carbonyl amide) pyridine and py-PTZ is 10-(4-picolyl) phenothiazine) were synthesized. Their photo-induced electron transfer (ET) reaction with electron acceptor methyl viologen (MV2+) in acetonitrile was studied by nanosecond laser flash photolysis at room temperature. Photoexcitation of 1 in the presence of MV2+ led to ET from the Re moiety to MV2+ generating Re(II) and methyl viologen radical (MV•+). Then Re(II) was reduced either by the charge recombination with MV•+ or by intramolecular ET from the attached PTZ, regenerating the photosensitizer Re(I) and forming the PTZ radical at 510 nm. In the case of 1b, the absorption for PTZ radical can be observed distinctly accompanied intermolecular ET, whereas not much difference at 510 nm can be detected for 1a on the time scale of the experiments. This demonstrates that the linking bridge plays a key role on the intramolecular ET in complex 1.
  • Research articles
    A novel intramolecular charge transfer fluorescent chemosensor highly selective for Cu 2+ in neutral aqueous solutions
    Qingxian LIAO, Aifang LI, Zhao LI, Yibin RUAN, Yunbao JIANG,
    2010, 5(2): 178-183. https://doi.org/10.1007/s11458-010-0114-8
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    A selective and sensitive intramolecular charge transfer (ICT) fluorescent chemosensor was designed for Cu2+ in neutral aqueous solutions of pH 7.0. The design of this totally water-soluble fluorescent chemosensor was based on the binding motif of Cu2+ to aminoacid, which is coupled to an ICT fluorophore bearing a 1,3,4-thiodiazole moiety in the electron acceptor. The formation of a 1:1 complex of Cu2+ to 2 was suggested to lead to fluorescence quenching. The quenching obeyed Stern-Volmer theory in neutral aqueous solution of pH 7.0 for Cu2+ over 5.0 × 10−7 to 3.0 × 10−5 mol·L−1, with a quenching constant of 1.8 × 105 L·mol−1 and a detection limit of 2.0 × 10−7 mol·L−1. The binding of Cu2+ to 2 can be fully reversed by addition of chelator EDTA, affording a reversible sensing performance.
  • Research articles
    Zn 2+ cation triggers self-assembly of cyclen into a stable metallogel
    Tianmin SHU, Junchen WU, Ying ZOU, Keyin LIU, Liqing CHEN, Tao YI,
    2010, 5(2): 184-192. https://doi.org/10.1007/s11458-010-0109-5
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    A novel type of ligands contained 1,4,7,10-tetrazacyclododecane and functionalized by two azobenzene moieties grafted with two alkyl chains was designed and synthesized. The ligands with long alkyl chains can form metallogels in the presence of Zn2+ cations. The formation of metallogel was followed by NMR and electronic spectral detection. The morphology of the xerogels is varied with the equivalent of Zn2+ cations and the concentration of the gel. Spectral and structural analysis indicated that the driving forces of the gel formation were attributed to intermolecular hydrophobic interactions between alkyl chains and π-π interaction between azobenzenes.
  • Research articles
    Synthesis of polypyridyl ruthenium complexes with 2-(1-aryl)-1H-imidazo[4,5-f]-1,10-phenanthroline ligand and its application for luminescent oxygen sensing
    Shaomin JI, Wanhua WU, Wenting WU, Qi YANG, Quan WANG, Xin ZHANG, Yubo WU, Jianzhang ZHAO, Huimin GUO,
    2010, 5(2): 193-199. https://doi.org/10.1007/s11458-010-0103-y
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    Polypyridyl ruthenium (Ru) complexes 1–3 were prepared. Their photophysical properties were investigated by UV-Vis absorption and luminescence emission spectra. The luminescent lifetimes of these Ruthenium complex were prolonged by more than 5 folds (t = 2.50 ms for complex 3) when compared with the parent Ru complex 1 (t = 0.45 ms). We propose that the extended luminescent lifetime of complex 3 is due to the equilibrium between 3MLCT state and the pyrene localized 3π-π* triplet state (3IL). The luminescent O2-sensing property of the complexes in solution and the IMPEK-C polymer film were studied, and the O2 sensing was quantified with the two-site model. The oxygen-sensing property of the Ru complexes can be improved by 104-fold with extension of the luminescent lifetimes. For example, the quenching constant KSV was improved from 0.0023 Torr−1 of 1 to 0.2393 Torr−1 for 3. Our results demonstrated a versatile approach for the preparation of Ru (II) polypyridine complexes with extended luminescent lifetimes as functional materials, for example, for luminescent oxygen-sensing applications.
  • Research articles
    A novel NIR violanthrone derivative with high electron-deficiency: effect of fluorescence on dicyanomethylene substitution
    Bo LIU, Duo FAN, Qiong ZHANG, Yu CHEN, Weihong ZHU,
    2010, 5(2): 200-207. https://doi.org/10.1007/s11458-010-0115-7
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    Near infrared (NIR) dyes attracted increasing interests in widely potential applications, such as fluorescent probe and living organism imaging, due to their low background signals from biomolecules, low light scattering and deep penetration, and low-cost excitation light sources. A novel NIR violanthrone derivative (VA-CN) with dicyanomethylene substitution was synthesized and fully characterized by 1H NMR, 13C NMR, HRMS, and IR spectrometry. It is demonstrated that the original planar conformation of violanthrone ring (the nine fused benzene rings) becomes twisted and unsymmetrical upon the incorporation of two strong electron-withdrawing dicyanomethylene units. Photophysical, electrochemical performances as well as distinct solvatochromic effects were studied in detail. Considering the low reduction potential (−0.56 V vs NHE), VA-CN could be considered as a good electron acceptor due to the strong electron deficiency resulted from dicyanomethylene group. A distinct increase in fluorescence was observed with 30-fold enhancement upon the addition of n-butyl amine. The reversible fluorescence “off-on” shows that VA-CN might be served as a promising fluorescent sensor for electron-rich amines.
  • Research articles
    Cooperative recognition of Cu 2+ based on amino acids tethered benzothiadiazoyl-bistriazoles
    Yi-Bin RUAN, Stephane MAISONNEUVE, Juan XIE, Chun LI, Jie TANG,
    2010, 5(2): 208-213. https://doi.org/10.1007/s11458-010-0117-5
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    Fluoroionophoric properties of benzothiadiazoyl-bistriazoyl amino acids derivatives toward metal ions were investigated by UV-Vis and fluorescence spectroscopy. Our results show that the water soluble lysine derivative 2 exhibited a significant selectivity toward Cu2+ in “on-off” type response in buffer solution at pH 7.4.
  • Research articles
    Single-source precursor route for overcoating CdS and ZnS shells around CdSe core nanocrystals
    Guanjiao CHEN, Wenjin ZHANG, Xinhua ZHONG,
    2010, 5(2): 214-220. https://doi.org/10.1007/s11458-010-0106-8
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    We reported a facile route for overcoating CdS and ZnS shells around colloidal CdSe core nanocrystals. To synthesize such double shelled core/shell nanocrystals, first, CdSe core nanocrystals were prepared in a much “greener” and cheap route, which did not involve the use of hazardous and expensive trioctylphosphine. Then, a low-cost and labor-saving route was adopted for the CdS and ZnS shell growth with the use of thermal decomposition of commercial available air stable single-source precursors cadmium diethyldithiocarbamate and zinc diethyldithiocarbamate in a non-coordinating solvent at intermediate temperatures. Powder X-ray diffraction patterns and transmission electron microscopy images confirm the epitaxial growth of the shell in the core/shell nanocrystals. The photoluminescence quantum yield of the resulting CdSe/CdS/ZnS core/shell nanocrystals can be as high as 90% in organic media and up to 60% after phase transfer into aqueous media. By varying the size of CdSe cores, the emission wavelength of the obtained core/shell nanostructures can span from 554 to 636 nm.
  • Research articles
    Two-photon absorption of photochromic diarylethene and its application to rewritable holographic recording
    Huanhuan LIU, Yi CHEN, Baoli YAO,
    2010, 5(2): 221-225. https://doi.org/10.1007/s11458-010-0112-x
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    A new photochromic diarylethene (1a) has been prepared. Both its photochromic behavior and nonlinear optical properties are investigated. 1a shows excellent ring-opening (lmax = 386 nm) and ring-closing (lmax = 652 nm) photoisomerization with UV-Vis light irradiation. With 800 nm femtosecond pulsed laser irradiation, 1a shows two-photon-induced photoisomerization, and a two-photon absorption cross-section (s = 423×1050 cm4·s per photon) is obtained by using two-photon induced fluorescence method. The applications of two-photon absorption of 1a to holographic recording has been also investigated. A two-photon induced micro-pattern is recorded on the diarylethene 1a-PMMA film with an femtosecond laser of 800 nm, 100 fs, 1 kHz, 50 mW.
  • Research articles
    Hyperbranched polyyne containing naphthalimide moiety as a fluorescent chemosensor for mercury ion
    Yi QU, Yihua JIANG, Jianli HUA,
    2010, 5(2): 226-233. https://doi.org/10.1007/s11458-010-0102-z
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    The development of multidimentional conjugated polymers as fluorescent sensor has been extremely attractive for detecting toxic ion in trace level. In this paper, a new hyperbranched polyyne with polytris(4-ethynylphenyl)amine (PTEPA) as the core, benzoyl thiourea-naphthalimide (NAP) as Hg (II) detected unit was designed and synthesized. The addition of Hg (II) ion transforms the thiourea unit of the chemodosimeter under THF conditions into an imidazoline moiety that is a much less electron-donating group, and hence results in a reduction in electron delocalization within the fluorophore. The emission maximum exhibits blue-shift and increase of fluorescent intensity. To confirm selectivity of the sensor towards mercury ions, it was also titrated with other divalent metal ions. No significant change was observed in the fluorescence spectra.
  • Research articles
    Polarization holographic optical recording based on a new photochromic diarylethene compound
    Hui LI, Shouzhi PU, Gang LIU, Weijun LIU, Baoli YAO,
    2010, 5(2): 234-240. https://doi.org/10.1007/s11458-010-0101-0
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    A new unsymmetrical photochromic diarylethene,namely1-[2-methyl-5-(p-N,N-dimethylaminophenyl)-3-thienyl]-2-[2-methyl-5-(3-methoxylphenyl)-3-thienyl]perfluorocyclopentene (1a), was synthesized. The compound showed good photochromism, high sensitivity and remarkable fatigue-resistance both in solution and in poly(methyl methacrylate) (PMMA) matrix with UV/Vis light irradiation. The absorption maximum of its closed-ring isomer was observed at 624 nm in PMMA amorphous film. It is a nice match for the wavelength of the recording laser (633 nm). Using this target compound as recording medium, four types of polarization holographic optical recordings were performed successfully using a He-Ne laser. The results showed that only the orthogonal circular polarization recording could obtain a hologram with high diffraction efficiency and high signal-to noise-ratio. With multiplexing recording technology, three types of polarization multiplexing holographic optical recordings, including angular multiplexing, polarization multiplexing, and angular plus polarization multiplexing holographic recording, were also carried out perfectly based on its photoinduced anisotropic phenomenon accompanying the photochromic reaction by photoirradiation. The results demonstrate that the multiplexing recording technology is an effective method to improve recording capacity when using diarylethene 1 as recording medium.
  • Research articles
    New ferrocenyl derivative with controllable aggregation-induced emission (AIE) characteristics
    Dong ZHANG, Liangliang ZHU, Hong LI, Jianhua SU,
    2010, 5(2): 241-246. https://doi.org/10.1007/s11458-010-0110-z
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    A novel molecular switch, 7-(N,N-diethylamino)-2-oxo-2H-chromen-4-yl ferrocene carboxylate (FCC), was synthesized and fully characterized by 1H NMR, 13C NMR, and HRMS. Taking advantage of the properties of ferrocene as an electron donor active unit and the coumarin as a fluorescent unit, the dyad FCC shows a fast and reversible redox-switchable fluorescence emission. In sharp contrast to most photoluminescent chromophores, FCC has a unique enhanced emission through aggregation. The change of electrochemical signals (CV and DPV) indicated that the ferrocene (Fc) unit of FCC could form inclusion complex with Me-b-cyclodextrin (CD). This inclusion complex could further weaken the aggregation-induced emission (AIE) effect remarkably. This advance paves the way to introduce AIE property into molecular devices applications.