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Abstract Four model compounds, for a tyrosine–histidine covalent bonding, 2-(5-imidazolyl)-4-methylphenol (C–C bonding in ortho-position at the phenyl group); 2′-(1-imidazolyl)-4-methylphenol (C–N bonding in ortho′-position at the phenyl group); 2-(5-imidazolyl)-4-H-phenol and 2-(5-imidazolyl)-4-H-phenol, at physiological pH have been
studied by UV-Vis absorption, steady-state and time resolved fluorescence spectroscopy. Their absorption and emission properties
are presented and discussed. The photophysical properties depend on the para-substituted phenyl group as well as on C–C/C–N bonding in the Phenol–Im linkage. The N position, N1–N3/N1–N4, in the imidazole group was found to be relevant. The results are discussed with relevance to the redox processes of Tyr
and to better understand the role of a tyrosine–histidine covalent linkage as found in cytochrome c oxidase.
Content Type Journal Article
Category Original Paper
DOI 10.1007/s10895-008-0411-5
Authors
Mariana Voicescu, Laboratoire de Spectroscopie Vibrationnelle et Electrochimie des Biomolécules UMR 7177, Institut de Chimie, CNRS-Université Louis Pasteur, 1 rue Blaise Pascal 67070 Strasbourg France
Martine Heinrich, Laboratoire de Spectroscopie Vibrationnelle et Electrochimie des Biomolécules UMR 7177, Institut de Chimie, CNRS-Université Louis Pasteur, 1 rue Blaise Pascal 67070 Strasbourg France
Petra Hellwig, Laboratoire de Spectroscopie Vibrationnelle et Electrochimie des Biomolécules UMR 7177, Institut de Chimie, CNRS-Université Louis Pasteur, 1 rue Blaise Pascal 67070 Strasbourg France
Abstract Polypropylene supports were functionalized by plasma-deposition of polymeric allylamine layers. The surface amino groups generated
were wet-chemically reacted with xanthene dyes resulting in fluorescent polymer films. The effect of polymer-attachment of
the dyes on their emission features was studied fluorometrically and different methods were tested to improve the fluorescence
properties of the films. Modification with cucurbit[6]uril (CB6) yields a moderately enhanced fluorescence as well as an improved
photostability. The observed effect is most likely due to CB6-induced rigidization of the linker molecules which seems to
reduce fluorescence quenching dye–dye and fluorophore–surface interactions.
Content Type Journal Article
Category Original Paper
DOI 10.1007/s10895-008-0407-1
Authors
Katrin Hoffmann, Bundesanstalt für Materialforschung und –prüfung Richard-Willstaetter-Str. 11 12489 Berlin Germany
Renate Mix, Bundesanstalt für Materialforschung und –prüfung Richard-Willstaetter-Str. 11 12489 Berlin Germany
Joerg F. Friedrich, Bundesanstalt für Materialforschung und –prüfung Richard-Willstaetter-Str. 11 12489 Berlin Germany
Abstract Dendrimers have been proposed as new carriers for drug delivery. They have distinctive characteristics, such as uniform and
controlled size, monodispersity and modifiable surface group functionality, which make them extremely useful for biomedical
applications. In this study, the binding capacity of water-soluble carbosilane dendrimers was examined. A double fluorimetric
titration method with 1-anilinonaphthalene-8-sulphonic acid (ANS) was used to estimate the binding constant and the number
of binding centers per dendrimer molecule. The data obtained suggest that ANS interacts non-covalently with the dendrimers.
Second generation dendrimers have an open, asymmetric structure that allows them to encapsulate ANS. The ability of the polymers
to interact with DNA was assessed by an ethidium bromide (EB) displacement assay. All the dendrimers studied bound to DNA
in competition with EB, though the strength of binding varied. Dendrimer interactions with a protein (BSA) were tested using
fluorescence quenchers. The dendrimers caused no conformation change in the protein, indicating that interactions between
carbosilane dendrimers and BSA are weak and occur preferentially at the protein surface.
Content Type Journal Article
Category Original Paper
DOI 10.1007/s10895-008-0412-4
Authors
Elzbieta Pedziwiatr, University of Lodz Department of General Biophysics 12/16 Banacha St. 90-237 Lodz Poland
Dzmitry Shcharbin, University of Lodz Department of General Biophysics 12/16 Banacha St. 90-237 Lodz Poland
Louis Chonco, Hospital General Universitario Gregorio Marañón Laboratorio de Inmunobiología Molecular Madrid Spain
Paula Ortega, Universidad de Alcalá, Campus Universitario Departamento de Química Inorgánica Alcalá de Henares Spain
F. Javier de la Mata, Universidad de Alcalá, Campus Universitario Departamento de Química Inorgánica Alcalá de Henares Spain
Rafael Gómez, Universidad de Alcalá, Campus Universitario Departamento de Química Inorgánica Alcalá de Henares Spain
Barbara Klajnert, University of Lodz Department of General Biophysics 12/16 Banacha St. 90-237 Lodz Poland
Maria Bryszewska, University of Lodz Department of General Biophysics 12/16 Banacha St. 90-237 Lodz Poland
Ma Angeles Muñoz-Fernandez, Hospital General Universitario Gregorio Marañón Laboratorio de Inmunobiología Molecular Madrid Spain
Abstract The objective of this study is to optimize the parameters in labeling near-infrared (NIR)fluorescent dye cypate to protein
drugs for in vivo optical imaging of drug distributions in animal model. l-ASparaginase (l-ASNase) was used as a protein drug model for the study. To achieve this goal, various labeling conditions, including different
catalysts, feed ratios of all components, pH conditions, temperatures, and reacting durations, were investigated. The dye-to-protein
(D/P) ratio and enzymatic activity were designated as the metric to evaluate the labeling process. The stability of the cypate–protein
conjugate in blood serum and its distribution in small animals were subsequently inspected. Results showed that feed ratio
of l-ASNase and the pH value played the most important role in adjusting the labeling efficiency. Reaction duration and temperature
had less effect on the dye-to-protein labeling properties. The optimal condition for the labeling of cypate to l-ASNase was 4 h reaction duration at 4 °C and pH 8.5 under catalysis by HOBt/HBTU. The dynamic distribution in animal model
displayed that the labeled l-ASNase firstly accumulated in liver and cleared from the enteron system. This study demonstrated that the NIR image system
combined with NIR probe has the capability to trace the dynamics of protein drugs in animals for drug development.
Content Type Journal Article
Category Original Paper
DOI 10.1007/s10895-008-0413-3
Authors
Huimin Qian, China Pharmaceutical University School of Life Science and Technology Nanjing People’s Republic of China
Yueqing Gu, China Pharmaceutical University School of Life Science and Technology Nanjing People’s Republic of China
Min Wang, China Pharmaceutical University School of Life Science and Technology Nanjing People’s Republic of China
Samuel Achilefu, Washington University School of Medicine Department of Radiology St. Louis MO USA
Abstract Transitions in the tryptophan microenvironment and secondary structure of two monocot lectins from Sauromatum guttatum and Arisaema tortuosum under different denaturing conditions were studied by steady state and time resolved fluorescence and CD spectroscopy. The
lectins exist as tetramers with a single tryptophan residue estimated per monomer, present in a polar environment. Quenching
with ionic quenchers showed predominantly electropositive environment for tryptophan residues. Acrylamide had maximum quenching
effect. A decrease in KI quenching due to lectin denaturation indicated redistribution of charges as a result of possible
conformational change. The two values for lifetimes of tryptophanyl population (1.2–1.4 and 6.3–6.4 ns) reduced substantially
on quenching or denaturation. Similarly, both the lectins showed a drastic loss of secondary structure in 5 M Gdn-HCl or 6 M
Urea or at pH 2.0 and below. For the first time araceous lectins, like legume lectins are shown to bind adenine. The presence
of a compact structure at alkaline pH 10.0–12.0 was observed in CD spectra.
Content Type Journal Article
Category Original Paper
DOI 10.1007/s10895-008-0409-z
Authors
Poorva N. Dharker, National Chemical Laboratory Department of Biochemistry Pune 411008 Maharashtra India
Sushama M. Gaikwad, National Chemical Laboratory Department of Biochemistry Pune 411008 Maharashtra India
C. G. Suresh, National Chemical Laboratory Department of Biochemistry Pune 411008 Maharashtra India
Vikram Dhuna, Guru Nanak Dev University Department of Molecular Biology and Biochemistry Amritsar 143005 Punjab India
M. Islam Khan, National Chemical Laboratory Department of Biochemistry Pune 411008 Maharashtra India
Jatinder Singh, Guru Nanak Dev University Department of Molecular Biology and Biochemistry Amritsar 143005 Punjab India
Sukhdev Singh Kamboj, Guru Nanak Dev University Department of Molecular Biology and Biochemistry Amritsar 143005 Punjab India
Abstract We investigate the relative photo-damage effects during one- and two-photon excitations and demonstrate that there exist fundamental
differences in the damage induced by a high repetition rate laser as compared to that of a CW laser. This difference is evident
from the degree of enhanced fluorescence intensity achieved by blanking the excitation with an optical chopper. Such an enhancement
in fluorescence intensity provides better signal-to-noise ratio that could have immediate applications in multiphoton imaging
of live specimens.
Content Type Journal Article
Category Rapid Communication
DOI 10.1007/s10895-008-0405-3
Authors
Arijit Kumar De, Indian Institute of Technology Kanpur Department of Chemistry Kanpur UP-208016 India
Debabrata Goswami, Indian Institute of Technology Kanpur Department of Chemistry Kanpur UP-208016 India
Abstract In an attempt to take full advantage of near-infrared part of the solar spectrum, Gd2(MoO4)3:Er3+ nanophosphors have been proposed as potential luminescent materials to enhance the response of the silicon solar-cell. Upon
excitation with low-energy near-infrared photons, intense upconverted emissions at 545, 665, 800, and 980 nm, for which energies
higher than the bandgap of silicon solar-cell, have been achieved with conversion efficiencies of 0.12%, 0.05%, 0.83%, and
1.35%, respectively. Development of nanophosphors for photovoltaic purposes could open up an approach in achieving high-efficiency
silicon-based solar-cell by means of the up-conversion of the sub-bandgap near-infrared part of the solar spectrum (E < 1.12 eV) to visible/near-infrared photons.
Content Type Journal Article
Category Original Paper
DOI 10.1007/s10895-008-0414-2
Authors
X. F. Liang, South China University of Technology Key Lab of Specially Functional Materials of Ministry of Education and Institute of Optical Communication Materials Guangzhou 510641 People’s Republic of China
X. Y. Huang, South China University of Technology Key Lab of Specially Functional Materials of Ministry of Education and Institute of Optical Communication Materials Guangzhou 510641 People’s Republic of China
Q. Y. Zhang, South China University of Technology Key Lab of Specially Functional Materials of Ministry of Education and Institute of Optical Communication Materials Guangzhou 510641 People’s Republic of China
Abstract In the context, a modified sol-gel technology was afford to the synthesis of rare earth composite ceramic phosphors MM′O3/CeO2 and MM′O3/CeO2: Pr3+ (M = Ca, Sr; M′ = Ti, Zr) with multicomponent hybrid precursors were composed. The micromorphology, particle size and photoluminescence
properties were studied with XRD, SEM and luminescent spectroscopy in detail. Both XRD and SEM indicated the particle sizes
were in the submicrometer range of 100 ∼ 300 nm. The photoluminescence for these ceramic phosphors were studied in details
with the different component of host (molecular ratio of Sr, Ca and Ti, Zr), presenting a broad spectral band in the visible
blue-violet region with the maximum excitation peak at 449 nm and a wide emission range with a maximum peak at 619 nm, which
was ascribed to be the characteristic transition of Pr3+ (1D2 → 3H4). These phosphors can be expected for visible light conversion (blue → red) materials. Especially it can be found that the
introduction of CeO2 can enhance the luminescence intensity of MM′O3 and MM′O3: Pr3+.
Content Type Journal Article
Category Original Paper
DOI 10.1007/s10895-008-0406-2
Authors
Bing Yan, Tongji University Department of Chemistry Shanghai 200092 People’s Republic of China
Xiaowen Cai, Tongji University Department of Chemistry Shanghai 200092 People’s Republic of China
Xiuzhen Xiao, Tongji University Department of Chemistry Shanghai 200092 People’s Republic of China
Abstract The photophysics and cyclic voltammetry of two novel phosphorescent thiones, 2,2-dimethyl-indan-1-one-3-thione (DMIKT) and 2,2-dimethyl-indan-1,3-dithione (DMIDT), and three known phosphorescent thiones, 4H-pyran-4-thione (PT), 4H-1-benzopyran-4-thione (BPT) and 2,2-dimethylindan-1-thione (DMIT), have been characterised and compared. The phosphorescence emission of DMIT, DMIKT and DMIDT extends from the red into the near-IR spectral region. The additional carbonyl or thione group of DMIKT and DMIDT causes a significant shift in the emission maxima to 680 nm compared to that of DMIT, at 637 nm, in perfluorinated hydrocarbons. In acetonitrile the emission maxima of DMIKT and DMIDT are at 696 and 706 nm, respectively, and the spectra show vibronic bands which extend out beyond 850 nm. There is a significant
reduction in triplet lifetime along this series (from 44 (±2) μs (DMIT) to 10 ((±0.8) μs (DMIKT) in perfluorinated solvents, and 8.6 (±0.5) (DMIT), 1.3 (±0.5) (DMIKT) and 0.35 (±0.07) μs (DMIDT) in acetonitrile), as well as a reduction in the rate constant for ground-state quenching of the triplet, (from 9.8 ((±0.9)
to 3.5 ((±0.6) and 1.3 ((±0.2) × 109 mol−1 dm3 s−1 for the same compounds). The addition of the C=O or C=S groups also causes a decrease in phosphorescence quantum yield with
the highest emission quantum yield obtained for DMIT (ΦP = 0.149 (±0.015)). Electrochemical studies show that while PT and BPT exhibit irreversible redox behaviour, DMIT, DMIKT and DMIDT all show at least one reversible reduction wave attributed to a one-electron process centred on the C=S moiety. The suitability
of these lumophores for use in OLEDs is discussed.
Content Type Journal Article
Category Original Paper
DOI 10.1007/s10895-008-0399-x
Authors
Rachel C. Evans, University of Wales Swansea Department of Chemistry Singleton Park Swansea SA2 8PP UK
Peter Douglas, University of Wales Swansea Department of Chemistry Singleton Park Swansea SA2 8PP UK
Christopher J. Winscom, Kodak European Research 332 Science Park, Milton Road Cambridge CB4 0FW UK
Abstract This report is devoted to the study of the low and room temperature photoluminescence and photoacoustic spectroscopy of the
Fe3+ impurity ion in the LiGa5O8–LiGaSiO4–Li5GaSi2O8 system. The sample was obtained by solid-state reaction between β-Ga2O3, Li2CO3, SiO2 and appropriated quantities of Fe2O3. It was investigated by X-ray diffraction to determine the formed phases and through photoluminescence, excitation and photoacoustic
spectroscopy measurements. The broad absorption and emission bands in the visible and near-infrared spectral regions presented
by that system constitute the motivation for this study. More specifically, the luminescence occurs over a large interval
of wavelengths, between 400 nm and 800 nm.
Content Type Journal Article
Category Original Paper
DOI 10.1007/s10895-008-0404-4
Authors
Sandra S. Pedro, Universidade do Estado do Rio de Janeiro Instituto de Física Rua São Francisco Xavier 524 Rio de Janeiro RJ Brazil
Ossamu Nakamura, Universidade Federal da Bahia, Campus Universitário de Ondina Instituto de Física Salvador BA 40210-340 Brazil
Ricardo B. Barthem, Universidade Federal do Rio de Janeiro Instituto de Física Cidade Universitária, Ilha do Fundão Rio de Janeiro RJ 21941-972 Brazil
Lilian P. Sosman, Universidade do Estado do Rio de Janeiro Instituto de Física Rua São Francisco Xavier 524 Rio de Janeiro RJ Brazil
Abstract Two novel and neutral benzimidazole derivatives-based anion receptors bearing a 1,10-phenanthroline fluorophore, N,N′-di-(2′-benzimidazolyl-methylene)-1, 10-phenanthroline-2,9-diamide (1) and N,N′-di-[2′-(benzimidazolyl-2′-) ethyl-]-1,10-phenanthroline-2,9-diamide (2), which exhibited turn-on and turn-off fluorescence
responses to various anions, were rationally designed and synthesized and their fluorescent response toward anions was investigated
in DMSO solution. In the process of anions binding, there were two different fluorescent responses in presence of anions:
a quenching of the fluorescence emission for F- and AcO- and an enhancement of the fluorescence emission for Cl−, Br− and I−. Two different luminescent mechanisms of the receptors 1 and 2 resulting from various anions were exploited to rationalize
quenching and enhancement of the fluorescence emission: a photo-induced electronic transfer mechanism (PET) and the increase
of the rigidity of the host molecules, respectively. In particular, chloride could be recognized selectively from the anions
tested according to changes of fluorescence spectrum.
Content Type Journal Article
Category Short Communication
DOI 10.1007/s10895-008-0400-8
Authors
Jie Shao, Nankai University Department of Chemistry Tianjin 300071 People’s Republic of China
Yanhong Qiao, Nankai University Department of Chemistry Tianjin 300071 People’s Republic of China
Hai Lin, Nankai University Key Laboratory of Functional Polymer Materials of Ministry of Education Tianjin 300071 People’s Republic of China
Huakuan Lin, Nankai University Department of Chemistry Tianjin 300071 People’s Republic of China
Abstract The quantitative structure-property relationship approach was performed to study the relative fluorescence intensity ratio
(R) of Eu(DBM)3Phen (DBM—dibenzoylmethane, Phen—1,10-phenanthroline) in 34 different solvents. The multilinear regression analysis and artificial
neural networks were employed to develop linear and nonlinear models, respectively. The proposed linear model contains six
descriptors, with the squared correlation coefficient r2 = 0.955 and the standard error of estimation s = 1.02. Better predictive results were obtained from the nonlinear model, with r2 = 0.987 and s = 0.51. The descriptors involved in the models were discussed in detail too.
Content Type Journal Article
Category Original Paper
DOI 10.1007/s10895-008-0403-5
Authors
Jie Xu, Wuhan University of Science and Engineering Key Laboratory of Green Processing and Functional Textiles of New Textile Materials, Ministry of Education Wuhan 430073 China
Qi Xiong, Wuhan University of Science and Engineering Key Laboratory of Green Processing and Functional Textiles of New Textile Materials, Ministry of Education Wuhan 430073 China
Biao Chen, University of Science and Technology of China Department of History of Science and Technology and Archaeometry Hefei 230026 China
Luoxin Wang, Wuhan University of Science and Engineering Key Laboratory of Green Processing and Functional Textiles of New Textile Materials, Ministry of Education Wuhan 430073 China
Li Liu, Wuhan University of Science and Engineering College of Electronics and Information Engineering Wuhan 430073 China
Weilin Xu, Wuhan University of Science and Engineering Key Laboratory of Green Processing and Functional Textiles of New Textile Materials, Ministry of Education Wuhan 430073 China
Abstract Two highly photostable yellow–green emitting 1,8-naphthalimides 5 and 6, containing both N-linked hindered amine moiety and a secondary or tertiary cation receptor, were synthesized for the first time. Novel compounds
were configured as “fluorophore–spacer–receptor” systems based on photoinduced electron transfer. Photophysical characteristics
of the dyes were investigated in DMF and water/DMF (4:1, v/v) solution. The ability of the new compounds to detect cations was evaluated by the changes in their fluorescence intensity
in the presence of metal ions (Cu2+, Pb2+, Zn2+, Ni2+, Co2+) and protons. The presence of metal ions and protons was found to disallow a photoinduced electron transfer leading to an
enhancement in the dye fluorescence intensity. Compound 5, containing secondary amine receptor, displayed a good sensor activity towards metal ions and protons. However the sensor
activity of dye 6, containing a tertiary amine receptor and a shorter hydrocarbon spacer, was substantially higher. The results obtained indicate
the potential of the novel compounds as highly photostable and efficient “off–on” pH switchers and fluorescent detectors for
metal ions with pronounced selectivity towards Cu2+ ions.
Content Type Journal Article
Category Original Paper
DOI 10.1007/s10895-008-0394-2
Authors
Vladimir B. Bojinov, University of Chemical Technology and Metallurgy Department of Organic Synthesis Kliment Ohridsky 8 1756 Sofia Bulgaria
Nikolai I. Georgiev, University of Chemical Technology and Metallurgy Department of Organic Synthesis Kliment Ohridsky 8 1756 Sofia Bulgaria
Paula Bosch, Institute of Science and Technology of Polymers, CSIC Juan de la Cierva 3 28006 Madrid Spain
Abstract The use of ozonation for the purification of drinking water can lead to the formation of bromate. The US Environmental Protection
Agency and the European Directive for human drinking water has lowered the regulatory level for bromate down to 10 μg l−1, such that methods must be developed for monitoring the formation of bromate, particularly in on-site situations. In the
present work we report a fluorometric method for the determination of bromate based on the reaction with carbostyril-124,
a compound that shows florescence mainly at pH values above 4 and, when bromated, generates a non-fluorescent product. The
reaction can thus be used as an indirect method for determination of the ion. The proposed method, which uses the flow injection
(FI) technique, allows online application and kinetic control of the variables affecting the process, together with shorter
reaction times, and it provides maximum sensitivity and selectivity. Under optimum conditions, it is possible to determine
the analyte within the 4–200 μg l−1 range, with a limit of detection of 0.9 μg l−1 and a relative standard deviation (n = 12, [
\textBrO\text3-
] = 5 and 30 μg l−1) of 3.2% and 2.6% respectively. The determination rate was ten samples per hour.
Content Type Journal Article
Category Original Paper
DOI 10.1007/s10895-008-0369-3
Authors
M. J. Almendral-Parra, University of Salamanca Departamento de Química Analítica, Nutrición y Bromatología, Faculty of Chemistry Plaza de la Merced s/n 37008 Salamanca Spain
A. Alonso-Mateos, University of Salamanca Departamento de Química Analítica, Nutrición y Bromatología, Faculty of Chemistry Plaza de la Merced s/n 37008 Salamanca Spain
M. S. Fuentes-Prieto, University of Salamanca Departamento de Química Analítica, Nutrición y Bromatología, Faculty of Chemistry Plaza de la Merced s/n 37008 Salamanca Spain
Abstract The complex [Tb0.1Gd0.9(TPTZ)(H2O)6]Cl3·3H2O was prepared through the reaction of 2,4,6-tris-(2-pyridyl)-1,3,5-triazine (TPTZ) with TbCl3:GdCl3 (0.1:0.9) in absolute ethanol at room temperature. Single crystal X-ray diffraction revealed that the metal atom is nine-coordinated
with three nitrogen atoms from one TPTZ ligand and six oxygen atoms from six water molecules. The complex emits intense green
fluorescence under ultraviolet light. The luminescence peaks correspond to the characteristic emission 5D4→7FJ (J = 3–6) transitions of the Tb3+ ion.
Content Type Journal Article
Category Original Article
DOI 10.1007/s10895-008-0401-7
Authors
Yan-Fang Zhao, Inner Mongolia University College of Chemistry and Chemical Engineering Hohhot 010021 China
Yong-Liang Zhao, Inner Mongolia University College of Chemistry and Chemical Engineering Hohhot 010021 China
Feng Bai, Inner Mongolia University College of Chemistry and Chemical Engineering Hohhot 010021 China
Yan Wang, Inner Mongolia University College of Chemistry and Chemical Engineering Hohhot 010021 China
Abstract MCM-41 mesoporous silica has been functionalized with aromatic carboxylic acids salicylic acid (Sal) and 2-hydroxyl-3-methylbenzoic
acid (HMBA) through co-condensation approach of tetraethoxysilane (TEOS) in the presence of the cetyltrimethylammonium bromide
(CTAB) surfactant as a template. Organic ligands salicylic acid or 2-hydroxyl-3-methylbenzoic acid grafted to the coupling
agent 3-(triethoxysilyl)-propyl isocyanate (TEPIC) was used as the precursor for the preparation of an organic–inorganic hybrid
materials. Novel organic–inorganic mesoporous luminescent hybrid containing Ln3+ (Tb3+, Eu3+) complexes covalently attached to the functionalized ordered mesoporous MCM-41, which were designated as Ln-Sal-MCM-41 and
Ln-HMBA-MCM-41, respectively, were obtained by sol–gel process. The luminescence properties of these resulting materials were
characterized in detail, and the results reveal that luminescent mesoporous materials have high surface area, uniformity in
the mesopore structure and good crystallinity. Moreover, the mesoporous material covalently bonded Tb3+ complex (Tb-Sal-MCM-41 and Tb-HMBA-MCM-41) exhibit the stronger characteristic emission of Tb3+ and longer lifetime than the corresponding Eu-containg materials Eu-Sal-MCM-41 and Eu-HMBA-MCM-41 due to the triplet state
energy of modified organic ligands Sal-TEPIC and HMBA-TEPIC match with the emissive energy level of Tb3+ very well. In addition, the luminescence lifetime and emission quantum efficiency of 5D0 Eu3+ excited state also indicates the efficient intramolecular energy transfer process in Tb-SAL-MCM-41 and Tb-HMBA-MCM-41.
Content Type Journal Article
Category Original Paper
DOI 10.1007/s10895-008-0402-6
Authors
Ying Li, Tongji University Department of Chemistry Shanghai 200092 People’s Republic of China
Bing Yan, Tongji University Department of Chemistry Shanghai 200092 People’s Republic of China
Abstract Cadmium sulfide semiconductor nanoparticles along with terbium ions were incorporated in silica xerogels through sol–gel route.
The optical absorption and emission spectra confirmed the formation of CdS nanoparticles along with terbium ions in the silica
gel. The optical bandgap and size of the CdS nanoparticle were calculated from the absorption spectrum. The TEM measurement
was also used to evaluate the average size of the CdS nanoparticles. The fluorescence spectra reveal that the intensity of
characteristic emission of terbium ions increases considerably in the presence of CdS nanoparticles even in the gel stage
itself and this avoids the need of heating gels at high temperatures. The branching ratios were calculated from the emission
spectra using the standard procedure.
Content Type Journal Article
Category Original Paper
DOI 10.1007/s10895-008-0398-y
Authors
P. V. Jyothy, Mahatma Gandhi University Kottayam India
K. A. Amrutha, Mahatma Gandhi University Kottayam India
Jose Gijo, Mahatma Gandhi University Kottayam India
N. V. Unnikrishnan, Mahatma Gandhi University Kottayam India
Abstract The emission spectra of the lanthanide chelates enable them to act as a donor for several acceptors emitting at different
wavelengths. Fluorescence resonance energy transfer between terbium(III) chelate labeled antibody Fab fragment (donor) and
a 17β-estradiol conjugated to Alexa Fluor 488, 555, 594 or 680 (acceptor) was employed to study the functionality of the terbium(III)
chelate as an efficient donor for several acceptors emitting from green to far-red. During measurement, the sensitized emission
of the acceptor was measured at acceptor specific wavelength. All the tested dyes proved to be efficient acceptors, and they
were successfully used in the competitive homogeneous E2 assay. The highest signal to background ratio and the best assay
performance was obtained with Alexa Fluor 680, due to the very low donor emission background at the far-red area. In addition,
the sensitized emission of both Alexa Fluor 488 and 680 could be measured simultaneously without significant cross talk.
Content Type Journal Article
Category Original Paper
DOI 10.1007/s10895-008-0397-z
Authors
Tiina Kokko, University of Turku Department of Biotechnology Tykistökatu 6A, 6th floor 20520 Turku Finland
Leena Kokko, University of Turku Department of Biotechnology Tykistökatu 6A, 6th floor 20520 Turku Finland
Tero Soukka, University of Turku Department of Biotechnology Tykistökatu 6A, 6th floor 20520 Turku Finland
Abstract Size effect of silver nano particles on the photophysical properties of 1,4-dihydroxy-2,3-dimethyl-9,10-anthraquinone (DHDMAQ)
have been investigated using optical absorption and fluorescence emission techniques. Silver nanoparticles of different sizes
have been prepared by Creighton method using magnetic stirrer and ultrasonic field. Quenching of fluorescence of DHDMAQ has
been found to increase with decrease in the size of the silver nanoparticles. Stern–Volmer quenching constants have also been
calculated.
Content Type Journal Article
Category Original Paper
DOI 10.1007/s10895-008-0372-8
Authors
M. Umadevi, Mother Teresa Women’s University Department of Physics Kodaikanal 624 102 Tamil Nadu India
P. Vanelle, University of Méditerranée Department of Organic Chemistry, UMR CNRS 6517, Faculty of Pharmacy 27 Bd Jean Moulin 13385 Marseille Cedex 5 France
T. Terme, University of Méditerranée Department of Organic Chemistry, UMR CNRS 6517, Faculty of Pharmacy 27 Bd Jean Moulin 13385 Marseille Cedex 5 France
Beulah J. M. Rajkumar, Lady Doak College Department of Physics Madurai India
V. Ramakrishnan, Madurai Kamaraj University Department of Laser Studies, School of Physics Madurai 625 021 India
